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Threats to seabirds: A global assessment

  • University of Cambridge / British Antarctic Survey

Abstract and Figures

We present the first objective quantitative assessment of the threats to all 359 species of seabirds, identify the main challenges facing them, and outline priority actions for their conservation. We applied the standardised Threats Classification Scheme developed for the IUCN Red List to objectively assess threats to each species and analysed the data according to global IUCN threat status, taxonomic group, and primary foraging habitat (coastal or pelagic). The top three threats to seabirds in terms of number of species affected and average impact are: invasive alien species, affecting 165 species across all the most threatened groups; bycatch in fisheries, affecting fewer species (100) but with the greatest average impact; and climate change/severe weather, affecting 96 species. Overfishing, hunting/trapping and disturbance were also identified as major threats to seabirds. Reversing the top three threats alone would benefit two-thirds of all species and c. 380 million individual seabirds (c. 45% of the total global seabird population). Most seabirds (c. 70%), especially globally threatened species, face multiple threats. For albatrosses, petrels and penguins in particular (the three most threatened groups of seabirds), it is essential to tackle both terrestrial and marine threats to reverse declines. As the negative effects of climate change are harder to mitigate, it is vital to compensate by addressing other major threats that often affect the same species, such as invasive alien species, bycatch and overfishing, for which proven solutions exist.
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Bird Conservation International (2012)22:134. © BirdLife International, 2012
Seabird conservation status, threats and priority
actions: a global assessment
We review the conservation status of, and threats to, all 346 species of seabirds, based on BirdLife
Internationals data and assessments for the 2010 IUCN Red List. We show that overall, seabirds are
more threatened than other comparable groups of birds and that their status has deteriorated faster
over recent decades. The principal current threats at sea are posed by commercial sheries (through
competition and mortality on shing gear) and pollution, whereas on land, alien invasive predators,
habitat degradation and human disturbance are the main threats. Direct exploitation remains
a problem for some species both at sea and ashore. The priority actions needed involve: a) formal and
effective site protection, especially for Important Bird Area (IBA) breeding sites and for marine IBA
feeding and aggregation sites, as part of national, regional and global networks of Marine Protected
Areas; b) removal of invasive, especially predatory, alien species (a list of priority sites is provided),
as part of habitat and species recovery initiatives; and c) reduction of bycatch to negligible levels, as
part of comprehensive implementation of ecosystem approaches to sheries. The main knowledge
gaps and research priorities relate to the three topics above but new work is needed on impacts of
aquaculture, energy generation operations and climate change (especially effects on the distribution
of prey species and rise in sea level). We summarise the relevant national and international
jurisdictional responsibilities, especially in relation to endemic and globally threatened species.
At present there is no readily accessible and up-to-date synthesis of the conservation status of the
worlds seabirds. Why is this important, given that only some 350 species (i.e. 3.5% of all birds)
are entirely dependent on marine habitats for at least part of their life cycle? Although relatively
few in number, seabirds as a group occur in all seas and oceans worldwide, and their role as
potential indicators of marine conditions is widely acknowledged (e.g. Boyd et al. 2006, Piatt et al.
2007, Parsons et al. 2008). Many studies use aspects of seabird biology and ecology, especially
productivity and population trends, to infer and/or correlate with aspects of the marine
environment, particularly food availability. Nevertheless, despite the importance of seabirds as
indicators, both regionally and globally, of many aspects of the functioning of marine systems,
the most important current challenge is to ensure the survival and improve the status of the
many seabird species which are already globally threatened with extinction and to maintain the
remainder in favourable conservation status. Compared with other groups of equivalent role in
marine systems, seabirds are exceptionally well-studied (Schreiber and Burger 2001). Conse-
quently, knowledge of their conservation status is more comprehensive and reliable than for any
comparable group of marine organisms (Vie et al. 2008). Therefore, both intrinsically and because
the status of seabirds is likely to reect the underlying state of important parts of the coastal and
oceanic systems of the world, we should take particular interest in how seabirds are faring, how
and why this status has changed in recent times, what actions are needed to address the main
current threats and what kind of baseline exists against which to measure future change.
In this paper we provide a brief global overview of the status of seabird species (focusing particularly
on globally threatened and Near Threatened species), especially in relation to jurisdictional re-
sponsibility. We identify the main reasons why seabirds are threatened and review priority actions to
address the main threats. Finally, we indicate priorities for research and monitoring and identify
particular knowledge gaps. Our analyses are global in scale and should be supplemented by reviews
and identication of priorities at the regional level (but using global Red List categories, as assessments
of extinction risk at the regional scale are largely lacking).
Our analyses are based on BirdLife Internationals assessments for the 2010 IUCN Red List
(available at and in summary form at
and data on IBAs held in BirdLifes World Bird Database (WBDB; available at
datazone/sites). Summary data are provided in Table S1in the online Supplementary Materials.
Both species and IBA data are compiled and regularly updated from reviews of published and
unpublished literature as well as information provided by a network of over 100 BirdLife Partner
organisations, hundreds of other institutions, and thousands of scientists, conservationists,
birdwatchers and local or species experts.
We follow the taxonomy of BirdLife International (2010a) and dene seabirds as species for
which a large proportion of the total population rely on the marine environment for at least part of
the year. With this circumscription, 346 species qualify, of which 282 meet a stricter denition
(excluding ducks, loons, etc.) used in some earlier reviews (e.g. Croxall et al. 1984). We subdivided
seabirds into three groups. Pelagic seabirdsare those that primarily use marine pelagic deep
water (sea above open ocean, typically .200 m in depth) and/or marine neritic pelagic continental
shelf water (sea above continental shelf or around near-shore oceanic islands, typically ,200 min
depth) excluding species that may occasionally use these habitats, but that are more typical of
coastal inshore waters. Coastal seabirds (year-round)are those that primarily use coastal inshore
water (sea along coasts, typically ,8km from the shoreline) throughout the year, excluding
species that may occasionally use this habitat, but do not do so typically. Coastal seabirds (non-
breeding season)are those that primarily use coastal inshore water during the non-breeding
season, excluding species that may occasionally use this habitat but do not do so typically.
Species on the IUCN Red List are placed into categories of extinction risk (ranging from Least
Concern, to Near Threatened, Vulnerable, Endangered, Critically Endangered, and Extinct) based
on quantitative criteria using information on population and range size, structure and trends
(IUCN 2001,2010). Vulnerable, Endangered and Critically Endangered species are referred to
collectively as threatened(IUCN 2001). Species for which there is insufcient information to
apply the criteria are classied as Data Decient (IUCN 2001, Butchart and Bird 2009). A small
number of Critically Endangered species are tagged as Possibly Extinct if they are, on the balance
of evidence, likely to be extinct, but for which there is a small chance that they may be extant and
thus should not be listed as Extinct until adequate surveys have failed to nd the species and
unconrmed reports have been discounted (IUCN 2010, Butchart et al. 2006).
In analyses of the numbers of seabird species by country we exclude vagrant records (as dened
in relevant national checklists, eld guides and handbooks; generally used for species for which
there are few records or that only occur sporadically and infrequently), but include those species
whose occurrence in a particular country is coded as uncertain (because maps of conrmed
distribution indicate that they are likely to occur in territorial waters, but no published records
have been traced). We consider conrmed resident or breeding species separately. We used GIS and
BirdLifes digitised speciesdistribution maps to determine occurrence of species in national
Exclusive Economic Zones (EEZs), Large Marine Ecosystems (LMEs; Sherman et al. 1993)andareas
of application of different Regional Fisheries Management Organisations (RFMOs). Boundaries for
J. P. Croxall et al. 2
EEZs were taken from VLIZ (2010), for LMEs from National Oceanic and Atmospheric
Administration (2010), and for RFMOs from each of the individual organisationswebsites.
Jurisdictions are as listed by the International Organisation for Standardization (ISO;
at July 2010; note that subsequently Tristan da Cunha (with Gough Island) was accorded a status
separate from St Helena.
Direction of current population trend was coded as increasing, stable, uctuating, decreasing or
unknown. Threats to species were classied using the IUCN/Conservation Measures Partnership
(CMP) threats classication scheme (Salafsky et al. 2008) with threats from all invasive alien
species identied to species level where possible, and threat magnitude calculated from scores for
timing, scope and severity following BirdLife International (2010b). Analyses of threats were
based on data for threatened species only (i.e. excluding Extinct, Near Threatened, Least Concern
and Data Decient species). Priority conservation and research actions were coded following the
IUCN/CMP Actions classication scheme (Salafsky et al. 2008).
We assessed trends in extinction risk using the IUCN Red List Index (RLI; Butchart et al. 2004,
2007) for 19882008 (the period between comprehensive assessments of all bird species for the
IUCN Red List), updated using current knowledge. The RLI is calculated from the number of
species in each Red List category and the number changing categories between assessments as
a result of genuine improvement or deterioration in status (category changes owing to improved
knowledge or revised taxonomy are excluded). RLI values relate to the proportion of species
expected to remain extant in the near future without additional conservation action. An RLI value
of 1.0equates to all species being categorised as Least Concern, and hence that none are expected to
go extinct in the near future. An RLI value of zero indicates that all species have become Extinct.
Important Bird Areas (IBAs) are key sites for the conservation of the worlds birds (e.g. BirdLife
International 2011). IBAs are places of international signicance for the conservation of birds
and are identied using a standardised set of data-driven criteria and thresholds based on
(1) globally threatened bird species, (2) restricted-range bird species (those with ranges smaller
than 50,000 km
), (3) biome-restricted assemblages (communities of birds characteristic of
a distinct biome) and (4) congregations (large aggregations of one or more species, e.g. migratory
waterbirds or breeding seabirds). IBAs are delimited so that, as far as possible, they: (a) are
different in character, habitat or ornithological importance from surrounding areas; (b) provide
the requirements of the triggerspecies (those for which the site qualies) while present, alone or
in combination with networks of other sites; and (c) are or can be managed in some way for
conservation. Terrestrial IBAs have been identied in almost all countries of the world, but for
the analyses presented here, data were incomplete and therefore omitted for 21 countries:
American Samoa, Argentina, Chile, Cook Islands, French Guiana, Guyana, Kiribati, Kyrgyzstan,
Nauru, New Caledonia, New Zealand, Niue, Papua New Guinea, Paraguay, Samoa, Solomon
Islands, Tokelau, Tuvalu, USA, Vanuatu and Wallis and Futuna Islands. Marine IBA identication,
i.e. of important areas in coastal waters and on the High Seas (Areas Beyond National Jurisdiction
(ABNJs)) for feeding and aggregation, is ongoing (BirdLife 2010e, Lascelles et al. 2012).
We examined growth in coverage of IBAs by nationally designated protected areas following
the approach of Butchart et al. (2010). Protected Area coverage data was taken from the WBDB
and is based on GIS overlays of IBA polygons with those nationally designated PAs for which
a boundary polygon was included in the 2010 release of the World Database on Protected Areas
(WDPA;, excluding internationally designated PAs and all sites with a status other
than designated. Where multiple protected areas overlapped an IBA, the date of designation of the
earliest protected area was used. Where data in the WDPA were incomplete or inaccurate, estimates
of protected area coverage of IBAs were updated by BirdLife Partners. For 257 protected areas (14%
of all PAs) with an unknown date of establishment, and for 88 IBAs (4.8%) known (from national
experts) to be partially protected but to an unknown extent, we randomly assigned a date or
proportion protected from another site in that country (doing this 10,000 times and plotting the
mean and 95% CIs to capture the uncertainty introduced by lack of data for a subset of sites); where
,2sites with known date/proportion protected occurred in the country we randomly selected from
Seabird global conservation status 3
all sites. We plotted trends in mean percentage area protected and number of sites completely
covered by protected area(s). Trends for Central America and Oceania were omitted as seabird IBA
identication is still very incomplete in these regions.
Results and Discussion
Of the 346 seabird species considered here (Table S1), 97 (28%) are globally threatened, 17 (5%)
in the highest category of Critically Endangered and a further 10% Near Threatened (Figure S1).
Only four species, all storm-petrels (White-vented Oceanites gracilis, MarkhamsOceanodroma
markhami, MatsudairasO. matsudairae and Ringed O. hornbyi) are regarded as Data Decient.
Three species are considered Extinct (Great Auk Pinguinus impennis, Large St Helena Petrel
Pterodroma rupinarum, Small St Helena Petrel Bulweria bifax) and two other species are
Possibly Extinct (Guadalupe Storm-petrel O. macrodactyla and Jamaica Petrel Pterodroma
caribbaea; included in Critically Endangered in Figure S1). Seabirds are more threatened than all
other groups of birds with similar numbers of species: 26% of parrots (Psittacidae; 374 species),
19% of pigeons/doves (Columbidae; 318 species), and 18% of raptors (Accipitridae; 238 species)
are threatened; all other similarly speciose bird families are equally or less threatened than the
global average (12%). Furthermore, dividing seabirds into pelagic and coastal species and
accounting separately for those species which only visit marine habitats outside their breeding
season (Figure 1) shows that pelagic seabird species are considerably more threatened than coastal
resident seabirds and that both are an order of magnitude more threatened than non-breeding
coastal seabirds. This likely reects that pelagic species tend to have small clutch sizes relative to
coastal species, reducing their capacity to absorb human-induced mortality and slowing recovery
following cessation of impacts.
Reviewing the pattern taxonomically (Figure 2) reveals that, of the main families (which
together account for 87% of species), the most threatened are the penguins and albatrosses/
petrels. These two orders (Sphenisciformes and Procellariiformes) represent nearly one half (43%)
of all seabirds and contain many pelagic species. After albatrosses, Diomedeidae, whose conservation
benets considerably from the Agreement on the Conservation of Albatrosses and Petrels (ACAP;, by far the most threatened group of seabirds are the gady petrels of the genera
Pterodroma and Pseudobulweria (and a special conservation internet forum has recently been
established to promote priority conservation action for these: Gady Petrel Conservation Group; The primary reasons for the classication of seabird species as
threatened (or Near Threatened), based on the IUCN Red List criteria they trigger, are summarised
Figure 1. Proportion of species in each IUCN Red List category for pelagic species, coastal
residents and coastal non-breeding visitors. Figures give number of species (for totals .5).
J. P. Croxall et al. 4
in Figure 3.Thus,ofthe132 threatened/Near Threatened species, 70 (53%)qualifybyvirtueof
very small population/range and a similar number (66;50%) by reason of rapid decline. Of
particular concern are those where small range or population is combined with decline (64 species;
48%). Noteworthy examples are six penguins (two Eudyptes and two Spheniscus), 17 gady petrels
and eight cormorants. Throughout, pelagic species are disproportionately represented in all
categories in comparison with coastal species.
As a broad generalisation, seabirds tend to have particularly small total breeding population
sizes, with 20% estimated to have fewer than 5,000 breeding pairs and about one half fewer than
50,000 pairs (Figure S2). Furthermore, 76 (23%) of these population estimates date from 2000 or
earlier (see Table S1), so this may be an optimistic portrayal of the current situation. The 15 species
whose global population estimates predate 1996 are: Royal Penguin Eudyptes schlegeli,Bullers
Shearwater Pufnus bulleri, Short-tailed Shearwater P. tenuirostris, Auckland Island Shag
Phalacrocorax colensoi,LavaGullLarus fuliginosus (all pre-1991), Emperor Penguin Aptenodytes
forsteri, Adélie Penguin Pygoscelis adeliae, Northern Royal Albatross Diomedea sanfordi,Black-
winged Petrel Pterodroma nigripennis, Cape Verde Shearwater Calonectris edwardsii,Jouanins
Petrel Bulweria fallax, Australasian Gannet Morus serrator,StewartIslandShagPhalacrocorax
chalconotus and Kerguelen Tern Sterna virgata. Most of these are Australasian in distribution and
many are restricted to single islands or island groups. In addition, even recent population estimates
are often of relatively low quality, with broad bands of uncertainty.
Thus most seabirds, especially pelagic ones, typically have small breeding populations and many
are likely to be in decline, demographic characteristics which severely limit their rate of recovery,
and a restricted number and range of breeding sites; this makes them disproportionately
vulnerable amongst birds to a wide range of threats.
Figure 2. Percentage of species in each IUCN Red List category for the major seabird families.
Figures give number of species.
Figure 3. The number of seabird species listed as threatened or Near Threatened for different
reasons (note that some species are listed for multiple reasons).
Seabird global conservation status 5
Nearly half (47%; 52% of those with known trends) of seabird species are known or suspected to
be experiencing population declines (Figure 4a). Nevertheless, 57 species (17%) are increasing;
many, such as the 17 gull species, doubtless due to their abilities to exploit close links with human
activities. This probably also accounts for increases in Northern Fulmar Fulmarus glacialis, some
Morus spp. gannets and possibly Black-footed Phoebastria nigripes and Campbell Albatrosses
Thalassarche impavida, although the last two are still recovering from past declines. Encourag-
ingly, a few species are increasing (e.g. Spectacled Petrel Procellaria conspicillata), often as
a result of long-term targeted conservation action (e.g. FeasPterodroma feae, Bermuda P. cahow
and Magenta P. magenta Petrels and Amsterdam and Short-tailed Albatrosses Diomedea
amsterdamensis and Phoebastria albatrus). As expected, pelagic species are disproportionately
more likely to be declining than coastal ones (52% versus 33%) but, perhaps surprisingly, the
non-breeding visitors to coastal waters have a similar proportion of decreasing species (46%) to
pelagic ones (Figure 4b); they also have a higher proportion of increasing species (25% versus
19% coastal and 12% pelagic).
Precise quantied rates of population decline or increase are available for very few species.
A broader, but less sensitive, measure of overall trends is provided by the Red List Index
(RLI, Butchart et al. 2004,2007), which measures trends in extinction risk and is virtually
the only trend indicator currently available for seabirds on a worldwide and/or regional basis. The
RLI is based on the movement of species through IUCN Red List categories owing to genuine
improvement or deterioration in status (i.e. re-categorisations owing to improved knowledge or
revised taxonomy are excluded). It shows (Figure 5a) that, over the last 20 years, seabirds have had
a substantially poorer conservation status than non-seabirds and that they have deteriorated faster
over this period. Seabirds are more threatened than a number of other similarly speciose groups
(e.g. raptors, pigeons, gamebirds and waterbirds), and are marginally more threatened than parrots.
However, among seabirds, pelagic species are more threatened and have deteriorated faster than
coastal species, and this difference is particularly pronounced for the albatrosses and large petrels
Figure 4. Current direction of trend for (a) all seabirds (n5346 species); (b) pelagic species,
coastal residents and coastal non-breeding visitors. Figures give number of species.
J. P. Croxall et al. 6
that are covered by ACAP (Figure 5b). Table S2summarises the background and evidence relating
to the 26 cases, involving 21 species, that qualied for reclassication to a higher or lower Red List
category during 1988-2008 (and also presents all changes that occurred during this period,
including as a result of improved knowledge or revised taxonomy).
National jurisdictional responsibility
The most important countries, in terms of the number of breeding seabird species and the total
number of species recorded within EEZ waters, are shown Figure 6a. In general terms, the
outcomes are rather similar; however, Japan, Mexico and several South American countries
(Argentina, Brazil, Peru, Ecuador), which are adjacent to important marine current systems
supporting large numbers of seabirds on migration and in winter, are in the top 10 (Japan, Mexico)
or top 20 (rest) overall but not in the top 20 for breeding species. In the top 10 of both categories
are USA, Canada, Russia, Australia, New Zealand, Chile and South Africa. If Overseas Territories
are included with the mainland jurisdiction, then France (with French Southern Territories) and
UK (with Pitcairn [Henderson], St Helena [Tristan da Cunha and Gough] and with or without the
Falkland Islands [Islas Malvinas]) would both be in the top ve of both categories.
If we focus on seabirds endemic or near-endemic (only in two, usually adjacent, countries) as
breeding species (Figure 6b), then a similar outcome results, albeit with New Zealand pre-eminent.
Figure 5. Red List Indices for (a) seabird and non-seabird species; (b) coastal and pelagic species
and those listed in the Agreement on the Conservation of Albatrosses and Petrels (ACAP).
Figures are for non-Data Decient extant species in 1988.
Seabird global conservation status 7
For single-country endemics (Table 1), the most important countries are New Zealand (33 species),
UK (eight, mainly on the Tristan da Cunha islands), Mexico (ve), Ecuador (ve, all in Galapagos),
Chile (four), Australia (four) and USA (three but with 21 species shared with either Mexico or
Canada). Even if we focus on threatened species (Figure S3), New Zealand retains pole position,
having more than double the number of threatened species of any other country. However, Chile
and South Africa hold the next largest number of threatened species, followed by France
(including French Southern Territories and French Polynesia), UK (including Tristan da Cunha,
South Georgia [Islas Georgias del Sur] and Falkland Islands [Islas Malvinas]). Australia (including
Heard and Macquarie Islands), followed by USA, Mexico, Peru and Russia complete the top 10.If
non-breeding species are included (Figure 6c), the distribution is somewhat more even and South
American countries more prominent, but the basic pattern is similar.
Therefore, to protect a considerable majority of the worlds seabirds, especially globally
threatened species, either when breeding or when foraging within EEZ waters, priority attention
Figure 6. The countries supporting the largest numbers of (a) seabird species; (b) endemic
breeding seabird species; (c) seabird species of conservation concern (breeding and non-breeding
species combined).
J. P. Croxall et al. 8
Table 1. Seabird species endemic to single countries/jurisdictions.
Country/Region (no. endemic species) Species
New Zealand (33) Fiordland Penguin Eudyptes pachyrhynchus, Snares Penguin
ĆEudyptes robustus, Erect-crested Penguin Eudyptes sclateri,
Yellow-eyed Penguin Megadyptes antipodes, Antipodean
Albatross Diomedea antipodensis, Northern Royal Albatross
Diomedea sanfordi, Southern Royal Albatross Diomedea
epomophora, Campbell Albatross Thalassarche impavida,
White-capped Albatross Thalassarche steadi, Chatham Albatross
Thalassarche eremita,Bullers Albatross Thalassarche bulleri,
White-headed Petrel Pterodroma lessonii, Magenta Petrel
Pterodroma magentae, Mottled Petrel Pterodroma inexpectata,
PycroftsPetrelPterodroma pycrofti, CooksPetrelPterodroma
cookii, Chatham Petrel Pterodroma axillaris, Westland Petrel
Procellaria westlandica, ParkinsonsPetrelProcellaria parkinsoni,
BullersShearwaterPufnus bulleri, Fluttering Shearwater Puf-
nus gavia,HuttonsShearwaterPufnus huttoni, New Zealand
Storm-petrel Oceanites maorianus, Campbell Island Shag Phala-
crocorax campbelli, New Zealand King Shag Phalacrocorax
carunculatus, Stewart Island Shag Phalacrocorax chalconotus,
Chatham Islands Shag Phalacrocorax onslowi, Auckland Islands
Shag Phalacrocorax colensoi, Bounty Islands Shag Phalacrocorax
ranfurlyi, Spotted Shag Phalacrocorax punctatus,PittIslandShag
Phalacrocorax featherstoni, Red-billed Gull Larus scopulinus,
Black-fronted Tern Sterna albostriata
Mexico (5) TownsendsShearwaterPufnus auricularis, Black-vented
ĆShearwater Pufnus opisthomelas,LeastStormPetrelHalocyp-
tena microsoma, Guadalupe Storm-petrel Oceanodroma macro-
dactyla, CraverisMurreletSynthliboramphus craveri
St Helena (to UK) (5) Tristan Albatross Diomedea dabbenena, Atlantic Yellow-nosed
ĆAlbatross Thalassarche chlororhynchos,AtlanticPetrelPtero-
droma incerta, Spectacled Petrel Procellaria conspicillata,Ascen-
sion Frigatebird Fregata aquila
Ecuador (5) Galapagos Penguin Spheniscus mendiculus, Waved Albatross
ĆPhoebastria irrorata, Galapagos Petrel Pterodroma phaeopygia,
Flightless Cormorant Phalacrocorax harrisi,LavaGullLarus
Chile (4) Juan Fernandez Petrel Pterodroma externa, Stejnegers Petrel
ĆPterodroma longirostris, De Filippis Petrel Pterodroma
delippiana, Pink-footed Shearwater Pufnus creatopus
Australia (4) Royal Penguin Eudyptes schlegeli, Shy Albatross Thalassarche
Ćcauta, Black-faced Cormorant Phalacrocorax fuscescens,
Pacic Gull Larus pacicus
USA (3) Hawaiian Petrel Pterodroma sandwichensis, Newells Shearwater
ĆPufnus newelli, Western Gull Larus occidentalis
Japan (2) Short-tailed Albatross Phoebastria albatrus, Matsudairas Storm-
Ćpetrel Oceanodroma matsudairae
Portugal (2) Zinos Petrel Pterodroma madeira, Monteiros Storm-petrel
ĆOceanodroma monteiroi
Argentina (2) White-headed Steamerduck Tachyeres leucocephalus, Olrogs
ĆGull Larus atlanticus
Antarctica (2) Emperor Penguin Aptenodytes forsteri, Antarctic Petrel Thalassoica
Seabird global conservation status 9
should be given to the geographical areas represented by New Zealand (with Australia), Chile
(with Peru, Ecuador), USA (with Canada, Japan and Russia), South Africa (with Namibia), UK and
France (only in respect of their overseas territories), Mexico, Brazil and Argentina (see Table 2).
Delivery of effective conservation of breeding sites and of EEZ waters in these nine regions
(16 countries) would take account of most of the needs of the 25% of seabird species which are
completely restricted to these areas and make a major contribution to the 92% of seabird species
whose ranges are included, at least in part.
Assessing threats to seabirds is a complex and somewhat subjective task. BirdLife International has
compiled an inventory, using the published literature and an extensive network of correspondents.
Some illustrations of the general conclusions from this are provided below (Figures 7a7c); it must
be emphasised that this part of the review is conned to threatened species, i.e. excluding Near
Threatened, Least Concern and Data Decient species.
Globally, of the top 10 threats to threatened seabirds (Figure 7a), invasive species (invariably
acting at the breeding site) potentially affect 73 species (75% of all threatened seabird species and
nearly twice as many as any other single threat, although in some cases the threat is of a potential
future impact). The remaining threats are fairly evenly divided between those acting mainly at the
breeding site: problematic native species (31 species, 32%), human disturbance (26 species, 27%),
infrastructure/commercial/residential development (14 species, 14%) and those acting mainly at
sea in relation to foraging, moulting or migration areas/aggregations: bycatch (40 species, 41%),
pollution (30 species, 31%), overshing or inappropriate spatial management of sheries
(10 species, 10%). Hunting and trapping (23 species, 24%) and energy production/mining
(10 species, 10%) affect both domains, the former more at breeding sites, the latter more in
relation to foraging areas, ight paths and yways. Climate change and severe weather (39 species,
40%), as presently assessed, largely reects adverse weather and climatic events at breeding sites
and the potential impact of sea level rise but is clearly an important driver of change that is
increasingly affecting seabirds in many ways, albeit mainly in the medium to long term (i.e. at
timeframes mostly outside those of relevance to IUCN Red List criteria). The relative importance
of threats is largely similar when only those of high impact are considered, although bycatch
becomes almost as signicant as the impacts of invasive alien species.
Table 1. Continued.
Country/Region (no. endemic species) Species
Fiji (2) Collared Petrel Pterodroma brevipes, Fiji Petrel Pseudobulweria
Réunion (to France) (2) BarausPetrelPterodroma baraui, Mascarene Petrel Pseudobulweria
Christmas Island (to Australia) (1) Abbotts Booby Papasula abbotti, Christmas Island Frigatebird
Fregata andrewsi
Canada (1) Thayers Gull Larus thayeri
Peru (1) Markhams Storm-petrel Oceanodroma markhami
French Southern Territories (1) Amsterdam Albatross Diomedea amsterdamensis
Falkland Islands (Islas Malvinas) (1) Falkland Steamerduck Tachyeres brachypterus
Pitcairn Islands (to UK) (1) Henderson Petrel Pterodroma atrata
Cape Verde (1) Cape Verde Shearwater Calonectris edwardsii
Brazil (1) Trindade Petrel Pterodroma arminjoniana
Spain (1) Balearic Shearwater Pufnus mauretanicus
Jamaica (1) Jamaica Petrel Pterodroma caribbaea
Bermuda (to UK) (1) Bermuda Petrel Pterodroma cahow
J. P. Croxall et al. 10
If pelagic seabirds are considered alone (Figure 7b), the pattern is generally similar, although
bycatch assumes a higher priority (particularly when comparing high-impact threats only). For
coastal species (Figure 7c) however, disturbance and hunting and trapping assume greater
signicance, with overshing of food resources, disturbance and pollution important if considering
high-impact threats only. The absence of bycatch from the top 10 coastal threats, however, may
simply reect the fact that the impacts of inshore/coastal gillnets and of artisanal shing are almost
completely undocumented, although likely widespread and important (Zydelis et al. 2009).
Overall, it is important to note that some threats, especially bycatch, coastal pollution and
overshing, are assessed to have higher impact on a larger proportion of the species they affect,
considerably increasing their overall importance.
Although these assessments of threats are based on data only for threatened species (97 in total),
there is no reason to believe that the pattern is greatly different for the 35 Near Threatened and
207 Least Concern species. The diversity of threats testies to the vulnerability of seabird species
to substantial actual and potential threats at all stages of their annual and life cycles. For Near
Threatened and Least Concern species it is likely that the relative importance of human
disturbance, development and consumption (hunting/trapping) would increase markedly, partic-
ularly for tropical species, for which major reductions in populations and/or breeding sites are
increasingly indicated but seldom quantied, especially across the whole range of the many wide-
ranging tropical seabird species.
Conservation action
In terms of recommended conservation actions, some indication of the main priorities for
threatened and Near Threatened species are provided in the BirdLife World Bird Database (based
on a review of the conservation literature and expert opinion; Figure 8). The classes used are rather
Table 2. Priority countries for seabirds, ranked according to total numbers of (a) breeding and non-breeding
species, (b) globally threatened and Near Threatened species, and (c) endemic species (restricted to one or two
countries). Overall rank is derived from the sum of ranks for the three parameters. Total number of countries /
territories 5239.
Country Diversity rank Threat rank Endemics rank Overall Rank
USA 1321
Chile 2232
New Zealand 6113
Australia 5444
Mexico 3845
South Africa 9576
Peru 11 7 7 7
Canada 4186 8
French Southern Territories 10 9 12 9
Russia 7151010
Argentina 12 6 15 11
Japan 8191012
Ecuador 13 21 12 13
Falkland Islands (Islas Malvinas) 17 12 17 13
Namibia 29 9 12 15
St Helena (to UK) 30 15 7 16
Brazil 14 11 28 17
China (mainland) 15 26 17 18
Norfolk Island (to Australia) 25 21 17 19
French Polynesia 37 12 17 20
Seabird global conservation status 11
broad and the data may not be consistent and comprehensive for all species, as they are based on
information collated for IUCN Red List assessments. Notwithstanding these caveats, the main
priorities are: a) control/eradication of invasive alien species; b) increased and enhanced site/area
Figure 7. Threats to threatened (a) seabirds (n5346 species); (b) pelagic seabirds (n5197
species); (c) coastal seabirds (n5146 species).
Figure 8. Priority conservation actions needed for threatened, Near Threatened and Data
Decient seabirds.
J. P. Croxall et al. 12
protection (i.e. formal protected area designation or other forms of recognised protection plus
effective implementation of appropriate management plans); c) improved legislation/regulation/
best-practice standards and effective implementation/enforcement of these (especially in marine
contexts). Other, more generic actions, such as education/awareness and accompanying stake-
holder involvement are also high priorities, as are some more species-specic activities, such as
harvest management, reintroductions and species recovery (as dened by Salafsky et al. 2008).
Although it is relatively straightforward to derive these generic recommendations for conserva-
tion action, it is usually costly and difcult (practically and/or politically) to implement them
effectively and at a sufcient scale to make a difference to the conservation status of seabird species.
However, considerable progress has been achieved in recent years in terms of the three highest
priority actions: protecting key sites (encompassing many more specic interventions), eradicating/
controlling invasive alien species and addressing seabird bycatch. In contrast, less progress has been
made in ensuring that ecosystem approaches underpin implementation of sheries management.
Site protection
One index of the most general level of protection afforded to seabird breeding sites is the coverage
by nationally designated protected areas of IBAs identied for seabird species. Thus, of the 1,820
terrestrial IBAs currently identied for seabirds (major areas currently incomplete are Antarctica,
many Pacic Islands, USA, Mesoamerica, Russian Arctic, East Asia, South-east Asia, parts of the
Indian Ocean and West Africa; however, there is no reason to believe that the properties of IBAs in
these areas will be substantially different than in the rest of the world), on average, 38% of the area
of these IBAs is covered by protected areas and 28% is completely covered (Figure 9a). This is an
improvement of about one order of magnitude since the 1950s1960s and an approximate doubling
of protection since the mid-1980s. It is concerning, however, that the rate of increase appears to
have reduced substantially since about 2000, perhaps because remaining unprotected IBAs are in
areas with the greatest land-use conicts, but possibly partly because of time-lags between countries
identifying IBAs, designating protected areas and providing data on these to the WDPA.
Trends in the coverage of seabird IBAs by protected areas in different regions are shown in
Figure 9b. It is perhaps unsurprising that Australasia, with a number of very large marine parks,
and Europe, with many important seabird breeding sites long protected at some level, achieve the
highest levels of protection. It is interesting, however, that both Asia (with relatively many sites)
and South America (with the fewest sites of any region) come next and that both are ahead of
North America and the Caribbean. Particularly in the Caribbean but probably in North America
generally designation of coastal protected areas has been severely constrained by the priority
accorded to human recreational and commercial development of coastal areas.
Finally, examining protection of IBAs at a national scale (Figure 10), on average, more than two-
thirds of the extent of IBAs is protected in France (including French Southern Territories), UK,
Ecuador (chiey by virtue of the Galapagos National Park), Netherlands, Denmark and Egypt.
Among the countries protecting more than 50% of the extent of their IBAs, Japan and Australia
both stand out in respect of the large number of breeding sites involved. At the other end of the
scale, countries with at least 10 seabird IBAs, for which preliminary data indicate that a mean of
,25% of IBA extent is covered by protected areas, include the Bahamas, Brazil, Estonia, Faroe
Islands, Iceland, Morocco, Oman, Saudi Arabia, Ukraine and Yemen.
Further analysis of these data (beyond the scope of this review) is needed to assess the main gaps
in protection for the most important terrestrial IBAs for seabirds as well as an assessment of the
practical effectiveness of this protection. The present analyses include protected areas in all IUCN
categories (IUCN and UNEP 2010) but for many, if not most, the actual protection may be purely
nominal. Indeed, an important challenge is to categorise each protected area according to the level,
nature and effectiveness of protection actually afforded to the seabirds in the IBA, including
whether any management plan (of relevance to seabirds) exists and whether this plan is being
implemented. Only when this is undertaken, in conjunction with monitoring the status of the
Seabird global conservation status 13
seabirds in the IBA, will a meaningful assessment of the level of protection accorded to breeding
seabirds at national, regional and global levels be feasible. Doing this is at least as high a priority as
any of the research actions noted below.
The foregoing discussion has dealt almost exclusively with protection of breeding sites.
Protection of key feeding and aggregation (e.g. for moult and on migration) areas is the essential
complementary conservation action. In order to address this, BirdLife International recently
extended its global IBA programme to include marine areas, especially seaward extensions around
breeding colonies, sites of coastal congregations of non-breeding birds, migration bottlenecks and
key pelagic sites. All these sites are likely to represent priority sites for protection and/or
management and more than 40 national BirdLife Partners are currently actively engaged in work
related to marine IBA identication and protection.
Some parts of the foraging ranges of seabirds are afforded protection by existing marine protected
areas at some IBAs. However, in nearly all cases, the size of the area included is too small or
inappropriately located to include the resources required bybreeding seabirds (BirdLife International
2010c). It is currently very difcult to estimate the number and proportion of marine IBAs
effectively protected, as marine IBA coverage is still patchy and incomplete on a global scale. The
process of marine protection for seabirds is perhaps the most developed globally in the European
Figure 9. Protected Area coverage of Important Bird Areas identied for (a) seabirds worldwide
(n51,820 sites); (b) seabirds in different regions (showing mean percentage area protected).
Figures indicate number of sites.
J. P. Croxall et al. 14
Union (EU), under its Birds Directive, but even here only around 1.5% of the EEZs of EU member
states have Special Protected Area (SPA) status. It is likely that the percentage is similar or smaller
for the majority of coastal nations globally.
Given that marine protected areas cover only about 1.17 % of the ocean (comprising 4.32%of
continental shelf areas but only 0.91% in off-shelf waters), i.e. an order of magnitude less than the
equivalent value (c. 10%) for terrestrial areas (Toropova et al. 2010,UN2010), it is hardly
surprising that establishing better protection, as well as better regulation and management of
relevant threats at sea, is the highest priority of all for those marine areas of greatest importance
to seabirds. Nevertheless the fundamental differences between protected areas on land and at sea,
particularly in relation to the large range of pelagic species and the dynamic nature of many of the
key habitat features that such species exploit, need to be recognised. Effective protected areas in
marine systems will need to be large and their management is likely to focus more on
management of threatening processes (particularly those of resource exploitation) than outright
prohibition of such activities.
In relation to marine areas of greatest importance for seabirds, relative priorities in terms of
EEZs are shown in Figure S4, based on data (as total species) in Figure 6a. The most important
countries are USA (147 species overall, 11 threatened), Mexico (109/14), Chile (103/22), Canada
(100/9), Australia (97/23), New Zealand (96/38), Japan (92/9), Russia (91/7), South Africa (82/16)
and Argentina (74/14). Other countries whose EEZs support 50 or more seabird species are China,
Peru, Brazil, Spain , France (and French Polynesia), UK (and Falkland Islands [Islas Malvinas] and
South Georgia [Islas Georgias del Sur]), Ireland, Portugal, Denmark, Ecuador, Colombia, Costa
Rica and India.
An important suite of marine areas are Large Marine Ecosystems (LMEs; Sherman et al. 1993),
63 areas that have been recognised as constituting discrete and coherent marine regions, particularly
from a resource-management perspective. Many of these are coastal, but most overlap the EEZs of
more than one country and/or extend into the High Seas. The overlap between the distribution of
seabirds and LMEs is illustrated in Figure S5and summarised in Table S3. It is not surprising that
the LMEs of most importance to seabirds include the Humboldt Current (with 17%morespecies
than any other area), California Current, New Zealand Shelf, East Central Australian Shelf,
Agulhas Current, Pacic Central-American Coastal, Kuroshio Current, Patagonian Shelf, Southeast
Figure 10. Countries with the highest proportion of their seabird Important Bird Areas
protected. Figures indicate number of sites.
Seabird global conservation status 15
Australian Shelf and West Bering Sea (all supporting .70 seabird species), with the Gulf of Alaska,
Benguela Current and East Bering Sea being the other LMEs supporting .60 species. Taken
together, appropriate management of the marine environment in these LMEs would make
a substantial contribution to the conservation of at least 275 seabird species (80% of the total),
including 62 (64%) of the globally threatened species.
For marine areas and habitats largely or exclusively on the High Seas, the main relevant
jurisdictions are the areas of application of the various RFMOs. The overlap between these and
seabird species is summarised in Table S3. This emphasises the potential importance of appropriate
environmental management in the vast areas where members of these RFMOs operate: the top
eight RFMOs all support more seabird species than any individual EEZ or LME, with 223 species
in the area of the Western and Central Pacic Fisheries Commission (WCPFC), more than double
the numbers in the Humboldt Current LME. The ve main tuna RFMOs are all in the top six
RFMOs for seabirds.
To address priority seabird conservation issues in the marine environment will therefore
require approaches that combine and coordinate actions in EEZs and on the High Seas (with
particular focus on those LMEs that straddle EEZs and High Seas). However without effective
action by the RFMOs with High Seas jurisdictions and responsibilities, many threats to seabirds
cannot be adequately addressed. Ensuring that sites/areas for seabirds are well represented within
proposed candidate Ecologically and Biologically Sensitive Areas (EBSAs) under the Convention
on Biological Diversity will be vital.
Eradication or control of invasive alien species
Over the last two decades, improved materials and techniques and considerable effort have led to the
successful removal of alien invasive species from many islands of substantial importance for breeding
seabirds. Thus, of the 25 most important sites identied in 1982 (Croxall et al. 1984), several have
been successfully cleared of at least some alien invasive species (e.g. feral cats removed from Isla de la
Plata, Ascension, Marion and Macquarie islands; feral goats from Isla de la Plata and South Trindade)
and appropriate plans are well advanced for several others. The success in removing rats Rattus spp.
from Campbell Island has stimulated the development of rodent removal plans for numerous other
islands. Those for Macquarie Island, Henderson (Pitcairn group) and South Georgia are currently
being implemented while plans are well developed for Palmyra, Wake, several islands in the Gambier
group and, subject to nal feasibility studies, for house mouse Mus musculus at Gough Island,
arguably the worlds most important site (and for general biodiversity as well as for seabirds) for
which alien eradication is the top priority (Wanless et al. 2007).
Many other islands of national and/or regional importance for seabirds have had rats, cats, dogs,
pigs, goats, rabbits and cattle removed in the last decade or so (e.g. Nogales et al. 2004, Angel et al.
2009). Indeed, by late 2006,332 successful rodent eradications (35 failed, 20 unknown outcome)
had been undertaken, with invasive rodents eradicated from 284 islands (Howald et al. 2007). As
techniques and materials are further improved, it is probable that, notwithstanding funding and
political constraints, most of the remaining top priority sites for seabirds could be cleared of
relevant important invasive aliens over the next decade or so. A list of seabird sites requiring
urgent attention, involving some 73 islands and 20 jurisdictions, is provided in Table 3. This list is
inevitably incomplete, with some key areas and islands still unsurveyed, especially in the Pacic,
but it does represent a synthesis of current expert knowledge and opinion. For many sites, to
develop further towards implementation will require consideration of potential benets to other
vertebrate taxa (especially mammals and reptiles) and to wider biodiversity. It will usually be
important to consider the full range of issues and opportunities, especially involving island
restoration and including translocations to former breeding sites, that often need to be assessed
before appropriate eradication decisions can be made (Mulder et al. 2011).
Thus, while it is relatively straightforward to provide indicative lists of important sites where
eradication of alien species would benet seabirds, and feasible to review and analyse these and
J. P. Croxall et al. 16
Table 3. A list of priority islands where eradication of invasive alien vertebrates would benet globally threatened seabirds or major multi-species colonies. (CR 5Critically
Endangered, EN 5Endangered, VU 5Vulnerable, NT 5Near Threatened, LC 5Least Concern, PE 5Possibly Extinct).
Country Island group: Island Seabird species (2010
IUCN Red List category)
Invasive alien species
(see Note 1)
Comments and other
taxa that would benet
Australia Macquarie Island Burrowing seabirds generally House Mouse, Black Rat,
European Rabbit
Eradication (re-)commenced
in May 2011
Lord Howe Island Providence Petrel (VU) Masked Owl, House
Mouse, Black Rat
Rodent eradication proposed
(see Note 2)
Christmas Island Christmas Island
Frigatebird (CR)
Cat, House Mouse, Rat spp.
Brazil S Trindade Island Trindade Petrel (VU) House Mouse Other seabirds. Goats now
Fernando de Noronha Boobies, tropicbirds, etc. Pig, Goat, Rat spp.
Canada Queen Charlotte Islands Ancient Murrelet (LC) Northern Raccoon, Brown
Rat, Black RatRhinoceros Auklet (LC)
Chile Chañaral Humboldt Penguin (VU) European Rabbit Peruvian Diving-petrel
(EN) formerly bred
Choros Peruvian Diving-petrel (EN) European Rabbit
Humboldt Penguin (VU)
Pan de Azucar Peruvian Diving-petrel (EN) Rat spp.
Humboldt Penguin (VU)
Isla Pajaros Uno Peruvian Diving-petrel (EN) Rat spp. Eradication planned
Humboldt Penguin (VU)
Juan Fernandez:
Alejandro Selkirk
Stejnegers Petrel (VU) Cat, Goat, House Mouse,
Brown RatJuan Fernandez Petrel (VU)
Juan Fernandez:
Robinson Crusoe
Pink-footed Shearwater (VU) Dog, Cat, Goat, Southern Coati,
Brown Rat, Black Rat,
European Rabbit
De Filippis
Petrel (VU) formerly
bred. Sheep
eradicated. Cattle
farmed and
Isla Mocha Pink-footed Shearwater (VU) Cat, House Mouse, Brown Rat
Islas Desventuradas:
San Felix
De Filippis Petrel (VU) Cat, House Mouse Boobies & terns
Islas Desventuradas:
San Ambrosio
De Filippis Petrel (VU) Goat, House Mouse
Seabird global conservation status 17
Table 3. Continued.
Country Island group: Island Seabird species (2010
IUCN Red List category)
Invasive alien species
(see Note 1)
Comments and other
taxa that would benet
China (mainland) Zhejiang Province:
Juishan Islands
Chinese Crested Tern (CR) Lesser Rice-eld Rat Several islands involved;
birds move between
islandsWuzhishen Islands Chinese Crested Tern (CR)
China (Taipei) Matsu Islands Chinese Crested Tern (CR)
Cook Islands Suwarrow Many seabird species Rat spp.
Ecuador Galapagos: Isabela Galapagos Penguin (EN) Cat, Dog, Donkey, Cattle, Pig,
House Mouse, Black RatGalapagos Petrel (CR)
Galapagos: Santa Cruz Galapagos Petrel (CR) Cat, Dog, Donkey, Pig, Goat,
Black Rat
Other seabirds; Galapagos
Rail Laterallus
spilonotus (VU)
Galapagos: Santiago Galapagos Petrel (CR) House Mouse, Black Rat Other seabirds; Galapagos Rail
Galapagos Penguin (EN)
Galapagos: Floreana Galapagos Petrel (CR) Black Rat, House Mouse,
Cat, Dog, Pig
Other seabirds; Galapagos Rail
Galapagos Penguin (EN)
Galapagos: San Cristóbal Galapagos Petrel (CR) Cat, Dog, Pig, House Mouse,
Black Rat
Other seabirds; Galapagos Rail
Isla de la Plata Waved Albatross (CR) House Mouse, Black Rat Other seabirds. Feral
cats and goats
eradicated in 2009
J. P. Croxall et al. 18
Table 3. Continued.
Country Island group: Island Seabird species (2010
IUCN Red List category)
Invasive alien species
(see Note 1)
Comments and other
taxa that would benet
France Clipperton Island Boobies & other ground-nesters Black Rat
Marquesas Islands: Fatu Hiva Phoenix Petrel (EN) Pig, Goat Other seabirds
White-throated Storm-
petrel (EN)
Marquesas Islands: Motu
Oa Hatu iti
Phoenix Petrel (EN) Pacic Rat Other seabirds
White-throated Storm-
petrel (EN)
Marquesas Islands: Mohotani Phoenix Petrel (EN) Pacic Rat, Black Rat
White-throated Storm-
petrel (EN)
Gambier Islands: Motu Teiku White-throated Storm-
petrel (EN)
? Shearwater spp.; other seabirds
Gambier Islands: Manui,
Makaroa, Kamaka
White-throated Storm-
petrel (EN)
Goat, Pacic Rat,
European Rabbit
Shearwater spp.;
eradications planned
for 2012
French Southern
Amsterdam and St Paul Islands:
Ile Amsterdam
Amsterdam Albatross (CR) Cat, Cattle, House Mouse,
Brown Rat
Cattle eradication
completed 2011Indian Yellow-nosed
Albatross (EN)
Crozet Islands: Ile aux Cochons White-chinned Petrel (VU) Cat Recolonisation of
larger petrels
Crozet Islands: Ile de la
White-chinned Petrel (VU) Black Rat Many other petrel species
Kerguelen Islands: Grand Terre White-chinned Petrel (VU) Cat, Reindeer, House Mouse,
Black Rat, European Rabbit
Many other petrel species
Kerguelen Islands: Ile Longue White-chinned Petrel (VU) Sheep, Black Rat Many other petrel species
Seabird global conservation status 19
Table 3. Continued.
Country Island group: Island Seabird species (2010
IUCN Red List category)
Invasive alien species
(see Note 1)
Comments and other
taxa that would benet
Japan (Kyushu): Eboshi-jima Japanese Murrelet (VU) Black Rat
(Kyushu): Koya-jima Japanese Murrelet (VU) Rat spp.
Muko-jima Seabirds Black Rat Eradication in 2008 unsuccessful
Muko-jima: Makotorishima Seabirds Black Rat Tristrams Storm-petrel (NT);
2008 rat eradication
Izu Islands: Torishima Japanese Murrelet (VU) Black Rat? Tristrams
Storm-petrel (NT);
other seabirds
Izu Islands: Onbase-jima Japanese Murrelet (VU) Black Rat
Izu Islands: Mikura-jima Japanese Murrelet (VU) Black Rat
Republic of
Kiribati Line Islands: Kiritimati Phoenix Petrel (EN) Cat, Pig, Pacic Rat Other seabirds
White-throated Storm
petrel (EN)
Birnie White-throated
Storm-petrel (EN)
Cat, Pig, Pacic Rat Other seabirds
Mexico Baja California: Guadalupe Guadalupe Storm-petrel (CR(PE)) Cat, Dog, House Mouse Goats eradicated c. 2009
XantusMurrelet (VU)
Baja California: Coronado Sur Ashy Storm-petrel (EN) House Mouse Goats eradicated 1999
Baja California: Los Coronados Craveris Murrelet (VU) Goat? Other seabirds.
Cats eradicated 1999
Revillagigedo Islands: Socorro Townsends Shearwater (CR) Cat, House Mouse Sheep nal eradication
in progress 2010
New Caledonia Walpole White-throated Storm-petrel (EN) Pacic Rat
J. P. Croxall et al. 20
Table 3. Continued.
Country Island group: Island Seabird species (2010
IUCN Red List category)
Invasive alien species
(see Note 1)
Comments and other
taxa that would benet
New Zealand Little Barrier Cooks Petrel (VU) Pacic Rat Successful eradication
conrmed 2006-2010
Chatham Islands: Pitt Island Pitt Island Shag (EN) Weka, Cat, Pig Chatham Petrel (EN)
formerly bred.
Chatham Island
Shag breeds on
offshore stacks
(e.g. European
Rabbit, Kokepa)
Chatham Island Shag (CR)
Kermadec Islands: Raoul Island Kermadec Petrel (LC) Pacic Rat, Brown Rat Successful eradication
of cats, rats conrmed
Kermadec Islands: Macauley Island Kermadec Petrel (LC) Pacic Rat Success of recent
(2006) eradication
to be conrmed (2011)
Peru San Gallan Peruvian Diving-petrel (EN) Dog, Goat, Rat spp.
La Vieja Peruvian Diving-petrel (EN) House Mouse
Lobos de Tierra Humboldt Penguin (VU) Cat Peruvian Diving-petrel
(EN) formerly bred.
Boobies & other seabirds
Portugal Madeira Zinos (Madeira) Petrel (EN) Cat, Pig, Goat, Black Rat
Puerto Rico Desecheo Island Boobies, terns Black Rat, Rhesus Macaque Goats recently eradicated.
Rhesus Macaque
eradication underway
Spain Balearic Islands (see Note 3):
Balearic Shearwater (CR) House Mouse, Black Rat Check on eradication
success at three colony
sites needed
Balearic Islands (see Note 3):
Balearic Shearwater (CR) Cat?, Dog?, Black Rat Cat and dog presence
from old references
Balearic Islands (see Note 3):
Balearic Shearwater (CR) Cat, Garden Dormouse,
Black Rat
Seabird global conservation status 21
Table 3. Continued.
Country Island group: Island Seabird species (2010
IUCN Red List category)
Invasive alien species
(see Note 1)
Comments and other
taxa that would benet
Balearic Islands (see Note 3):
Balearic Shearwater (CR) House Mouse, Black Rat Check on eradication
success at Dragonera
and Malgrats needed
Balearic Islands (see Note 3):
Balearic Shearwater (CR) Cat, Pine Marten, Garden
Dormouse, House Mouse,
Black Rat
United Kingdom
Overseas Territory
Pitcairn Islands: Henderson Henderson Petrel (EN) Pacic Rat Other Pterodroma petrels;
endemic landbirds.
undertaken 2011
Pitcairn Islands: Oeno Phoenix Petrel (EN) Pacic Rat Cats removed 1997
South Georgia
(Islas Georgias del Sur)
White-chinned Petrel (VU) Reindeer, House Mouse,
Brown Rat
Other seabirds:
endemic landbirds.
Rodent eradication
commenced 2011
St Helena, Ascension and
Tristan da Cunha:
Gough Island
Tristan Albatross (CR) House Mouse Grey Petrel (NT),other
seabirds, endemic
landbirds, exceptional
endemic invertebrate
Atlantic Petrel (EN)
St Helena etc: Tristan da Cunha
(main island)
Atlantic Petrel (EN) House Mouse, Black Rat Other seabirds,
especially recolonizing
burrowing petrels
Atlantic Yellow-nosed
Albatross (EN)
J. P. Croxall et al. 22
Table 3. Continued.
Country Island group: Island Seabird species (2010
IUCN Red List category)
Invasive alien species
(see Note 1)
Comments and other
taxa that would benet
USA Farallon Islands: South-east
Ashy Storm-petrel (EN) House Mouse
Alaska: Aleutian Islands Ancient Murrelet (LC) Arctic Fox, Red Fox, Rat spp.
Cassins Auklet (LC)
Crested Auklet (LC)
Least Auklet (LC)
California Channel Islands Xantuss Murrelet (VU) Cat, Rat spp. Other seabirds. Rats
eradicated from Anacapa in
2002, cats from San Nicolas in
Craveris Murrelet (VU)
Northern Line Islands: Palmyra Boobies & other ground-
Rat spp. Eradication planned
Note 1. Cat, Pig, Goat, Reindeer, Dog, Donkey, Cattle refer to feral animals. Scientic names: House Mouse Mus musculus; Black Rat Rattus rattus; European Rabbit
Oryctolagus cuniculus; Masked Owl Tyto novaehollandiae; Feral cat Felis catus; Feral pig Sus domesticus; Feral goat Capra hircus, Pacic Rat Rattus exulans; Feral reindeer
Rangifer tarandus; Brown Rat Rattus norvegicus; Northern Raccoon Procyon lotor; Feral dog Canis familiaris; Southern Coati Nasua nasua; Lesser Rice-eld Rat Rattus
losea; Donkey 5Feral donkey Equus asinus; Feral cattle Bos taurus; Weka Gallirallus australis; Rhesus Macaque Macaca mulatta; Garden Dormouse Eliomys quercinus;
Pine Marten Martes martes; Arctic Fox Alopex lagopus; Red Fox Vulpes vulpes
Note 2. See Lord Howe Board (2009).
Note 3. Additional colony-specic details made available from Conselleria de Medi Ambient, Govern de les Illes Balears via P. Arcos and M. McMinn (in litt., 2011).
Seabird global conservation status 23
similar lists for other taxa in order to derive conservation-related priorities, implementation of
successful eradications still remains challenging, especially from islands with resident human
populations (Oppel et al. 2011). In these circumstances the biological priorities rapidly become
subordinate to the socio-economic and political (including land tenure) realities, at least in terms
of building the support from stakeholder partnerships that will be essential for any eradication
implementation to be feasible or successful. Implementation of appropriate bio-security
procedures, especially following successful eradications, is also a top priority.
Seabird bycatch
This issue has only been apparent for about two decades (Brothers 1991, Croxall 2008). Neverthe-
less, seabird bycatch is the most pervasive and immediate threat to many albatross and petrel species
in both coastal waters and on the High Seas. The problem is largely being tackled in four
complementary ways. These involve: a) using long-term demographic studies of relevant seabird
species, linked to observational and recovery data to identify the cause of population declines (e.g.
Croxall et al. 1998,Tucket al. 2004, Poncet et al. 2006); b) risk assessments, based on spatio-
temporal overlap between seabird species susceptible to bycatch and effort data for sheries likely to
catch them (e.g. Waugh et al. 2008;Filippiet al. 2010;Tucket al. in press); c) working with
multinational and international bodies (e.g. FAO and RFMOs) to develop and implement
appropriate regulations for the use of best-practice techniques to reduce or eliminate seabird
bycatch (see below) and; d) working with shers (and national shery organisations) to assist cost-
effective implementation of these mitigation techniques (see below). In terms of point b), the use of
modern data on seabird distribution, derived from remote-recording studies (satellite tracking and
geolocators) has been essential, with the BirdLife Global Procellariiform Tracking Database
(BirdLife International 2004) being a crucial tool for identifying actual and potential bycatch
hotspotsin coastal waters and on the High Seas.
In relation to point c), the most important organisations include the Food and Agriculture
Organisation of the United Nations (FAO; particularly for best-practice advice for addressing bycatch
within the context of implementation of the FAO International Plan of Action for Reducing
Incidental Catch of Seabirds in Longline Fisheries - see
and ACAP (whose Seabird Bycatch Working Group has rapidly become a leading forum for technical
advice on the implementation of specic mitigation measures to eliminate seabird bycatch, further
developing the pioneering work of the Working Group on Incidental Mortality Associated with
Fishing of the Convention for the Conservation of Antarctic Marine Living Resources (CCAMLR)).
However, despite attempts to reduce the level of seabird bycatch by some tuna RFMOs, the
extent of implementation of effective measures remains largely inadequate. The following
measures are required to improve shery performance and reduce seabird bycatch in all RFMOs,
especially those involved in management of tuna and related species: a) universal adoption and
implementation of best-practice scientic advice on mitigation measures to reduce seabird bycatch;
b) improved data collection through at-sea observer programmes; and c) full use of appropriate
monitoring, surveillance and compliance measures. Whereas in 2004 none of the ve tuna RFMOs
had enacted seabird bycatch conservation measures, by 2010 four of the ve had at least one such
measure in place. So, while much improved implementation is still needed to reduce and document
seabird bycatch levels, there has been some progress in recent years towards better management of
key sheries in respect of non-target species.
At the practical level (and in terms of point d) above), BirdLife Internationals Albatross Task
Force (ATF), the worldsrst international team of bycatch mitigation instructors, was
established in 2006 to meet an urgent need for skilled practitioners to work at the grassroots
levelwith shers on-shore and at-sea to reduce seabird bycatch to negligible levels. The ATF
currently works in seven countries in South America and southern Africa and has demonstrated
in South Africa and Chile that bycatch reductions of .80% can be achieved in pelagic longline
and trawl sheries with the adoption of cost-effective bycatch mitigation measures (BirdLife
J. P. Croxall et al. 24
Global Seabird Programme 2010). The ATF is actively involved in the development and at-sea
trialling of new mitigation measures that when exported to and adopted by RFMO sheries have
the potential to make major contributions to reducing seabird bycatch in coastal and High Seas
pelagic longline sheries.
Other actions
Most of the other actions necessary to protect seabirds are considerably more difcult, either
practically or politically, to achieve. Thus, implementation of ecosystem approaches to shery
management is still entirely inadequate, especially in sheries whose target species are over-
exploited or fully exploited; similarly, signicant reduction/elimination of seabird mortality due to
hydrocarbon pollution requires continuing, coordinated national and international action to
achieve anything resembling best-practice regulation and management, even in territorial waters.
Coastal habitats, both on land and at sea are under threat as never before. Accelerating development,
both industrial and recreational (and including energy generation and aquaculture), combined with
growing and ubiquitous chronic pollution (oil, pesticides, etc), the acute impacts of ever more frequent
environmental accidents and, in many areas, increasing depredations for human sustenance, are
putting many populations and species of seabird at increasing risk. Where effective protection of
breeding and feeding sites can be achieved, hope remains; in many places, however, where seabirds
breed or feed on and close to coasts accessible to humans, the prognosis appears bleak.
In addition to some of the above initiatives, which are operating at the scale of entire islands
and/or habitats and therefore usually addressing simultaneously threats to several seabird
species effective progress may often be achieved and coordinated through developing and
implementing appropriate Species Actions Plans. At least 87 seabird species (25% of the total and
43% of all globally threatened species) have had recent action/recovery plans (or their close
equivalents) developed (Table 4).
Research priorities
The main research actions recommended (from the BirdLife World Bird Database, based on
a review of the conservation literature and expert opinion) as a basis for, or complement to,
conservation action are summarised in Figure 11. While recognising that these data would benet
greatly from further expert scrutiny and evaluation, particularly to ensure consistent treatment
between areas and species, four generalisations are feasible.
First, it is self-evident that to understand the trends in seabird populations and species, whether
on national, regional or global bases, more and better coordinated monitoring is badly needed, as
a minimum to permit evaluation of population size and trends for as many species as possible,
particularly those already in adverse conservation status. All existing data should be collated,
standardised where feasible and made widely and freely available.
Second, for a number of species, the threats they face need to be identied or much better
understood before any remedial action is feasible. Thus causes of decline for species like Stellers
Eider Polysticta stelleri, Kittlitzs Murrelet Brachyramphus brevirostris, Northern and Southern
Rockhopper Penguins Eudyptes moseleyi and E. chrysocome and Sooty Shearwater Pufnus
griseus, are little understood, nor are the threats facing many poorly known species, such as
numerous storm-petrel species and Ivory Gull Pagophila eburnea. In more specic cases, the
magnitude of threat from invasive alien predators needs assessing for species like Phoenix and
Tahiti Petrels Pterodroma alba and Pseudobulweria rostrata (generally in the Pacic), Magenta
Petrel Pterodroma magentae (Chatham Islands), Goulds Petrel P. brevipes (New Caledonia),
Grey Petrel Procellaria cinerea (Gough Island), Heinroths Shearwater Pufnus heinrothi
(Solomon Islands) and doubtless many others.
Seabird global conservation status 25
Table 4. Global or regional Species Action Plans (or close equivalents) for seabirds. (Note that this list does
not include brief outline plans, such as those for all Australian birds in Garnett and Crowley (2000) nor more
generic national plans, such as Environment Australia (2001). Red List category abbreviations follow Table 3).
Species 2010 IUCN
Red List
Scope Reference
Stellers Eider Polysticta stelleri VU Europe/USA Pihl (2001), USFWS (2002)
Common Eider Somateria mollissima LC Circumpolar CAFF (1997)
Common Eider Somateria mollissima LC Regional USFWS (2006)
King Eider Somateria spectabilis LC Regional CAFF (1997)
Spectacled Eider Somateria scheri LC Global CAFF (1997), USFWS (2009)
White-winged Scoter Melanitta fusca LC Regional Jensen and Lutz (2007)
Southern Rockhopper Penguin
Eudyptes chrysocome
VU Global BirdLife International (2010d)
Northern Rockhopper Penguin
Eudyptes moseleyi
EN Global BirdLife International (2010d)
Fiordland Penguin Eudyptes pachyrhynchus VU Global Taylor (2000)
Snares Penguin Eudyptes robustus VU Global Taylor (2000)
Erect-crested Penguin Eudyptes sclateri EN Global Taylor (2000)
Yellow-eyed Penguin Megadyptes antipodes EN Global Taylor (2000)
Little Penguin Eudyptula minor LC Regional Taylor (2000)
Waved Albatross Phoebastria irrorata CR Global ACAP (2008)
Short-tailed Albatross Phoebastria albatrus VU Global EAJ (1993), USFWS (2008)
Black-footed Albatross Phoebastria nigripes EN Global Naughton et al. (2007)
Laysan Albatross Phoebastria immutabilis NT Global Naughton et al. (2007)
Antipodean Albatross Diomedea antipodensis VU Global Taylor (2000)
Amsterdam Albatross Diomedea amsterdamensis CR Global Government of France (2011)
Northern Royal Albatross Diomedea sanfordi EN Global Taylor (2000)
Southern Royal Albatross Diomedea epomophora VU Global Taylor (2000)
Light-mantled Albatross Phoebetria palpebrata NT Regional Taylor (2000)
Campbell Albatross Thalassarche impavida VU Global Taylor (2000)
White-capped Albatross Thalassarche steadi NT Global Taylor (2000)
Chatham Albatross Thalassarche eremita CR Global Taylor (2000)
Salvins Albatross Thalassarche salvini VU Global Taylor (2000)
Grey-headed Albatross Thalassarche
VU Regional Taylor (2000)
Bullers Albatross Thalassarche bulleri NT Global Taylor (2000)
Northern Giant-petrel Macronectes halli LC Regional Taylor (2000)
Broad-billed Prion Pachyptila vittata LC Regional Taylor (2000)
Fairy Prion Pachyptila turtur LC Regional Taylor (2000)
Fulmar Prion Pachyptila crassirostris LC Regional Taylor (2000)
Baraus Petrel Pterodroma baraui EN Global Salamolard (2008)
Trindade Petrel Pterodroma arminjoniana VU Global Neves et al. (2006)
Kermadec Petrel Pterodroma neglecta LC Regional Taylor (2000)
Hawaiian Petrel Pterodroma sandwichensis VU Global Note 1
Feas Petrel Pterodroma feae NT Global Heredia et al. (1996),
Zino et al. (1996) (Note 2)
Zinos Petrel Pterodroma madeira EN Global Heredia et al. (1996),
Zino et al. (1995)
White-headed Petrel Pterodroma lessonii LC Regional Taylor (2000)
Magenta Petrel Pterodroma magentae CR Global Taylor (2000)
Great-winged Petrel Pterodroma macroptera LC Regional Taylor (2000)
Mottled Petrel Pterodroma inexpectata NT Global Taylor (2000)
Pycrofts Petrel Pterodroma pycrofti VU Global Taylor (2000)
Cooks Petrel Pterodroma cookii VU Global Taylor (2000)
White-necked Petrel Pterodroma cervicalis VU Global Taylor (2000)
Black-winged Petrel Pterodroma nigripennis LC Regional Taylor (2000)
J. P. Croxall et al. 26
Table 4. Continued.
Species 2010 IUCN
Red List
Scope Reference
Chatham Petrel Pterodroma axillaris EN Global Taylor (2000)
White-chinned Petrel Procellaria aequinoctialis VU Regional Taylor (2000)
Westland Petrel Procellaria westlandica VU Global Taylor (2000)
Parkinsons Petrel Procellaria parkinsoni VU Global Taylor (2000)
Grey Petrel Procellaria cinerea NT Regional Taylor (2000)
Bullers Shearwater Pufnus bulleri VU Global Taylor (2000)
Flesh-footed Shearwater Pufnus carneipes LC Regional Taylor (2000)
Pink-footed Shearwater Pufnus creatopus VU Global CEC (2005), Saez and
Hodum (2007)
Sooty Shearwater Pufnus griseus NT Regional Taylor (2000)
Balearic Shearwater Pufnus mauretanicus CR Global Aguilar (1999), BirdLife
International (2002),
Arcos (2011)
Newells Shearwater Pufnus newelli EN Global Note 1
Fluttering Shearwater Pufnus gavia LC Global Taylor (2000)
Huttons Shearwater Pufnus huttoni EN Global Taylor (2000), DoC (2006)
Little Shearwater Pufnus assimilis LC Regional Taylor (2000)
Grey-backed Storm-petrel Garrodia nereis LC Regional Taylor (2000)
White-faced Storm-petrel Pelagodroma marina LC Regional Taylor (2000)
White-bellied Storm-petrel Fregetta grallaria LC Regional Taylor (2000)
European Storm-petrel Hydrobates pelagicus LC Regional Newbery et al. (1998)
Common Diving-petrel Pelecanoides urinatrix LC Regional Taylor (2000)
Red-necked Grebe Podiceps grisegena LC Global ODonnel and Fjeldså (1997)
Great Crested Grebe Podiceps cristatus LC Global ODonnel and Fjeldså (1997)
Horned Grebe Podiceps auritus LC Global ODonnel and Fjeldså (1997)
Black-necked Grebe Podiceps nigricollis LC Global ODonnel and Fjeldså (1997)
Australasian Gannet Morus serrator LC Regional Taylor (2000)
Large Pied Cormorant Phalacrocorax varius LC Regional Taylor (2000)
Campbell Island Shag Phalacrocorax campbelli VU Global Taylor (2000)
New Zealand King Shag Phalacrocorax
VU Global Taylor (2000)
Stewart Island Shag Phalacrocorax chalconotus VU Global Taylor (2000)
Chatham Islands Shag Phalacrocorax onslowi CR Global Taylor (2000)
Auckland Islands Shag Phalacrocorax colensoi VU Global Taylor (2000)
Bounty Islands Shag Phalacrocorax ranfurlyi VU Global Taylor (2000)
Pitt Island Shag Phalacrocorax featherstoni EN Global Taylor (2000)
European Shag Phalacrocorax aristotelis LC Regional Aguilar and Fernández (1999),
Gallo-Orsi (2003)
Spotted Shag Phalacrocorax punctatus LC Global Taylor (2000)
Audouins Gull Larus audouinii NT Global Lambertini (1996),
Heredia et al. (1996),
Gallo-Orsi (2003)
Red-billed Gull Larus scopulinus LC Global Taylor (2000)
Black-billed Gull Larus bulleri EN Global Taylor (2000)
Roseate Tern Sterna dougallii LC Regional Newbery (1999)
Black-fronted Tern Sterna albostriata EN Global Taylor (2000)
Common Guillemot Uria aalge LC Circumpolar CAFF (1996)
Thick-billed Guillemot Uria lomvia LC Circumpolar CAFF (1996)
Kittlitzs Murrelet Brachyramphus brevirostris CR Global Balogh (2009)
1. The Action Plan for Newells Shearwater and Hawaiian Petrel is in preparation by a group of biologists
at the State of Hawaii Division of Forestry and Wildlife (DOFAW) and the U.S. Fish and Wildlife Service
(H. Freifeld and N. Holmes in litt. 2011)
2. Revised and updated at
Seabird global conservation status 27
The impact of light pollution is a particular concern for Goulds Petrel Pterodroma leucoptera
(in New Caledonia), Baraus and Mascarene Petrels P. baraui and Pseudobulweria aterrima
(Reunion),Newells Shearwater Pufnus newelli (Hawaii) and Ashy Storm-petrel Oceanodroma
homochroa and may need investigating for a number of other species. Fisheries interactions are
deemed potentially important to investigate for a wide range of species, but particularly so for
some cormorant species in pot sheries (e.g. Chatham Islands Shag Phalacrocorax onslowi) and
for many species in gillnet sheries, especially alcids and murrelets (notably Kittlitzs, Xantuss
Synthliboramphus hypoleuca, CraverisS. craveri and Japanese S. wumizusume) and several
Spheniscus penguin species. Assessing the impact of direct exploitation by humans is a particular
concern for tropical seabird species generally, especially at the few remaining major multi-species
colonies in South-east Asia, as well as wherever inshore artisanal sheries are being undertaken.
Third, for other species, the priority is a better understanding of aspects of life history,
distribution and ecology in order to understand their potential vulnerability to particular threats.
This is particularly mentioned in respect of demographic studies for species like Northern and
Southern Rockhopper Penguins, several Pterodroma petrels and Newells Shearwater and for
relatively unstudied restricted-range species like Black-faced Cormorant Phalacrocorax fusces-
cens and Kerguelen Tern Sterna virgata. Better knowledge of foraging distribution is required for
many species, especially those susceptible to bycatch but also for boobies (especially Abbotts
Booby Papasula abbotti) and frigatebirds, as well as most Pterodroma petrels. Studies outside the
breeding season, particularly of long-distance migrants and of juveniles of almost all species, are
of particular importance.
Fourth, for some species groups, modern taxonomic and genetic research is vital to understand
the nature of gene ow between populations and the inuence this may have on taxonomic
ranking and on consequent conservation action. Particular candidates for such work are the species
complexes involving Little and Audubons Shearwaters, Pufnus assimilis and P. lherminieri,
Collared and Goulds Petrels Pterodroma brevipes and P. leucoptera, Trindade and Herald Petrels
Pterodroma arminjoniana and P. heraldica, Fregetta storm-petrels and the Leucocarbo group of
Southern Hemisphere cormorants.
Finally, for a very few seabird species, their breeding colonies still remain to be discovered.
Prime examples are New Zealand Storm-petrel Oceanites maorianus, Fiji Petrel Pseudobulweria
macgillivrayi and Ringed Storm-petrel Oceanodroma hornbyi.
Overall, some of the more wide-ranging and important needs for research and associated
activities relate to assessing the severity of the threat and the status of seabird species potentially at
high risk because of: a) predation from invasive alien species; b) direct exploitation by humans; and
c) direct and indirect impact of artisanal shing practices, particularly gillnets.
Figure 11. Priority research topics for threatened, Near Threatened and Data Decient seabirds.
J. P. Croxall et al. 28
In many cases, appropriate action plans may need developing, but most outcomes should be
directly linkable to actions already being undertaken as part of the three major ongoing activities:
site protection, invasive alien species eradication and bycatch mitigation.
In addition, enhanced research is desirable on the potential effects on seabirds of:
a) acute mortality events, including those caused by pollution and harmful algal blooms;
b) aquaculture. This is possibly a lower priority for seabirds than for other, less mobile,
marine taxa;
c) energy generation in coastal and offshore marine habitats. There is much work to be
done, drawing on and generalising from existing experience to inform marine spatial
planning, not least in areas where seabird research is less well advanced and coastal
development is accelerating;
d) climate change. The main priority is to identify the seabird species and populations that
are likely to be most susceptible to sea level rise, as this may have immediate relevance to
existing and developing plans for management actions in relation to protected areas, alien
invasive species eradications and translocations (e.g. Bermuda Petrel). In respect of
potential changes in ocean dynamics, which may have substantial effects on seabird
populations worldwide, one perspective is that if we do not act effectively now to counter
all the other threats confronting seabirds, many populations will not be around by the
time these changes come into effect! Nevertheless, understanding the seabird commu-
nities, species and populations most likely at risk from major shifts in ocean conditions
might assist in developing management actions for those that we have some prospect of
saving and sustaining. This should include research on impacts of ecosystem-level
changes that alter predator-prey and competitive interactions between species.
To address the multiplicity of problems confronting the global ocean and the seabirds dependent on
it which are amongst the most visible and iconic of its inhabitants (as well as the best studied)
will require concerted endeavour at all levels from research to policy, complemented by the
exceptional effort needed to implement actions to address the conservation and management
priorities. For the global seabird community, it is imperative to share and combine resources, data
and expertise more effectively. In particular: 1) a high priority is to develop effective in-
tercommunication networks between existing databases to underpin a range of conservation and
management objectives. Particular goals should include: a) creating a World Seabird Colony
Register (which would complement the BirdLife IBA database); b) developing interoperable
databases for seabird monitoring studies, permitting instantaneous overviews of status and
productivity at sites worldwide; c) linking seabird at-sea distribution data from remote tracking
and at-sea surveys; and d) establishing a new database for seabird mortality events (whether of
unknown cause or due to e.g. oil pollution or harmful algal blooms); 2) all available data on seabird
distribution need to contribute to the identication of candidate sites for marine protected areas (and
for best-practice marine-managed areas) both within national EEZs and especially on the High Seas.
Ensuring that sites/areas for seabirds are well represented within proposed candidate EBSAs under
the Convention on Biological Diversity will be vital; 3) improved access to information on habitat
restoration, especially for seabird islands, including developing an agreed register of priority sites
for eradication of alien invasive species, together with advice on best-practice techniques is urgently
needed; and 4) enhanced worldwide collaboration is needed to address seabird-shery interactions,
especially bycatch, noting the likelihood of increasing problems from gillnet bycatch and from
commercial exploitation of forage sh (anchovies, krill, etc.).
Even if we are unable to deliver all of this, we probably already know enough to: a) to
implement the research and conservation priorities already identied; b) scope the data gaps that
are priorities for addressing tomorrows challenges; c) establish mechanisms for advocating and
Seabird global conservation status 29
resourcing the implementation of these priorities; and d) ensure that seabirds are thoroughly
linked to the other main initiatives seeking to understand better the dynamics of the ocean and to
conserve (and manage sustainably where appropriate) its biodiversity.
In many cases, seabirds will be exemplary models, as well as agships, for such endeavours. If
we cannot generate the commitment and momentum to establish new levels and orders of
collaborative interaction on behalf of seabirds and oceans, then we can only expect to watch their
destruction from the sidelines.
Supplementary Material
The online supplementary materials for this article can be found at
We are grateful to the thousands of individuals and organisations, in particular the BirdLife
Partners, who contribute to BirdLifes Red List assessments and documentation of the status of
seabirds and/or to the identication, monitoring and conservation of IBAs for seabirds. We thank
the many colleagues who provided comments on our text or on the data on which it is based.
A draft of the paper was circulated to all 800 attendees at the World Seabird Conference; we are
most grateful for the many responses (too many to acknowledge individually) and particularly
appreciate the thorough reviews by Jez Bird, Ian Nisbet, Richard Phillips and Cleo Small. In
respect of alien invasive species we are much indebted to researchers at the University of
California, Santa Cruz (Don Croll, Erin McCreless, Kelly Newton, Dena Spatz, Bernie Tershy)
and Island Conservation (Karl Campbell, Nick Holmes) whose input, especially to the table of
sites, was invaluable. For additional comments we thank also Steve Creswell, Esteban Frere, Peter
Hodum, Guillermo Luna, Thierry Micol, Steffen Oppel, Ivan Ramirez, Mayumi Sato, Alejandro
Simeone, Clare Stringer, Ross Wanless and Carlos Zavalaga. We also thank Jörn Scharleman for
help with preparation of Figure 7, Sue Patterson for assistance throughout the development of the
paper and Rory McCann for help with data compilation. We are most grateful to the reviewers of
the nal draft and to Peter Ryan for extensive editorial comment and advice.
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J. P. Croxall et al. 34
... The number of species in each IUCN Red List category in 2018, by seabird order, is shown in threats affecting all seabird species globally has been conducted using data collated from more than 900 publications and a standardized assessment approach based on the IUCN 2019) (Dias and others, 2019). ...
... The downlisting of species improved knowledge (e.g., new colonies discovered and taxonomy revision) rather than a genuine improvement in their status. Gaviiformes ( Climate change has been reported to have already caused declines in almost 100 seabird species (Dias and others, 2019). For example, changes in sea surface temperature during late winter were associated with declines in the population growth rate of the black-browed albatross (Thalassarche melanophris), primarily through effects on prey availability and subsequent juvenile survival (Jenouvrier and others, 2018). ...
... Mandatory mitigation measures have also been introduced within some areas of national jurisdiction and some parts of the high seas, including, for example, line weighting, night setting, bird-scaring lines and area closures (Brothers and others, 1999;Abraham and others, 2017). There is evidence that the number of threatened seabird species affecthas more than doubled in the past decade (Croxall and others, 2012;Dias and others, 2019), although this increase is at least in part due to increased understanding in that area. ...
Full-text available
A summary of information about seabirds for the second world ocean assessment published in August 2021
... and VanderWerf, 2022), are among the most threatened groups of marine organisms (Dias et al., 2019), and are impacted by invasive species, overexploitation, climate change, fisheries bycatch, and pollution (Boersma et al., 2001;Croxall et al., 2012;Dias et al., 2019;Rodríguez et al., 2017). Marine birds can be adversely affected by OWED through displacement due to avoidance or habitat alteration, or through direct mortality due to collision (Goodale and Milman, 2016;Hamer et al., 2014;Langhamer, 2012;Lieber et al., 2021;Linley et al., 2007;van Berkel et al., 2020;Voous, 1961). ...
... and VanderWerf, 2022), are among the most threatened groups of marine organisms (Dias et al., 2019), and are impacted by invasive species, overexploitation, climate change, fisheries bycatch, and pollution (Boersma et al., 2001;Croxall et al., 2012;Dias et al., 2019;Rodríguez et al., 2017). Marine birds can be adversely affected by OWED through displacement due to avoidance or habitat alteration, or through direct mortality due to collision (Goodale and Milman, 2016;Hamer et al., 2014;Langhamer, 2012;Lieber et al., 2021;Linley et al., 2007;van Berkel et al., 2020;Voous, 1961). ...
... Anthropogenic threats to marine birds, while numerous, are relatively well known (Dias et al., 2019;Spatz et al., 2014). Some of these threats have proven solutions that provide significant population benefit (Brooke et al., 2018;Jones et al., 2008;Spatz et al., 2017), and thus may be good candidates for compensatory mitigation actions. ...
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Offshore wind energy development (OWED) is rapidly expanding globally and has the potential to contribute significantly to renewable energy portfolios. However, development of infrastructure in the marine environment presents risks to wildlife. Marine birds in particular have life history traits that amplify population impacts from displacement and collision with offshore wind infrastructure. Here, we present a broadly applicable framework to assess and mitigate the impacts of OWED on marine birds. We outline existing techniques to quantify impact via monitoring and modeling (e.g., collision risk models, population viability analysis), and present a robust mitigation framework to avoid, minimize, or compensate for OWED impacts. Our framework addresses impacts within the context of multiple stressors across multiple wind energy developments. We also present technological and methodological approaches that can improve impact estimation and mitigation. We highlight compensatory mitigation as a tool that can be incorporated into regulatory frameworks to mitigate impacts that cannot be avoided or minimized via siting decisions or alterations to OWED infrastructure or operation. Our framework is 2 intended as a globally-relevant approach for assessing and mitigating OWED impacts on marine birds that may be adapted to existing regulatory frameworks in regions with existing or planned OWED.
... These species are affected directly by incidental capture (bycatch) or collision with fishing vessels and indirectly by overfishing, which changes the marine food web and increases competition for the same resources (Cury et al., 2011;Scales et al., 2018). Approximately 42 % of all seabird species are listed as globally threatened or near threatened, and 56 % of the species with a known trend are in decline (Dias et al., 2019). Albatrosses scavenge opportunistically and are attracted to vessels by the availability of discards and baited hooks, making them particularly susceptible to bycatch (Anderson et al., 2011;Phillips et al., 2016). ...
Bycatch is a conservation concern for marine biodiversity, including seabirds. Analyses of spatio-temporal overlap are an important tool for identifying areas and periods where birds are most at risk, but until recently were only possible at coarse scales using aggregated data on fishing effort. Here, we integrated data from loggers that record GPS positions of birds at sea and scan the surroundings to detect vessel-radar transmissions, with the positions of fishing vessels obtained from the automatic identification system, to identify areas, gear types and flag states representing most bycatch risk for wandering albatrosses (Diomedea exulans) of different life-history stages and sexes. We recorded 157 foraging trips of adult breeders, and 34 tracks of sabbatical breeders, 29 immatures and 31 juveniles. Overall, 55 % of birds encountered and 43 % of birds visited fishing vessels (i.e. were within 30 km and 5 km, respectively). Fine-scale overlap was particularly high for breeders during incubation and post-guard chick-rearing when birds travelled to the Patagonian Shelf break. Only 23 % of all encounters involved vessel visits. Our study found the greatest overlap was with set (demersal) longliners, particularly those from South Korea but also including the Falkland Islands, United Kingdom and Chile, and to lower extents, trawlers flagged to Argentina and Uruguay, and drifting (pelagic) longliners flagged to Brazil, Portugal and Taiwan. These fleets vary greatly in terms of bycatch rates. This study highlights the importance of covering the full range of life-history stages, and the advantages of vessel-detecting loggers and fine-scale analyses for improving risk assessments.
... Seabirds are more threatened than comparable groups of birds (Croxall et al., 2012). A recent global assessment found that more than 30% of the sea ducks are negatively affected by marine (fisheries bycatch and pollution) and terrestrial (alien species and hunting/trapping) threats (Dias et al., 2019). All the sea duck species in this risk assessment, i.e., long-tailed duck, common scoter, and velvet scoter, are categorized as threatened or near threatened on the Norwegian Red List for Species (Artsdatabanken, 2021) because of decreasing population size trends. ...
Technical Report
Full-text available
Scientific Opinion of the Panel on Biodiversity of the Norwegian Scientific Committee for Food and Environment
... Seabirds are one of the most threatened species groups on the planet (Dias et al. 2019). Seabirds face threats both when breeding on land and while foraging at sea. ...
Full-text available
Seabirds are highly threatened, including by fisheries bycatch. Accurate understanding of offshore distribution of seabirds is crucial to address this threat. Tracking technologies revolutionised insights into seabird distributions but tracking data may contain a variety of biases. We tracked two threatened seabirds (Salvin’s Albatross Thalassarche salvini n = 60 and Black Petrel Procellaria parkinsoni n = 46) from their breeding colonies in Aotearoa (New Zealand) to their non-breeding grounds in South America, including Peru, while simultaneously completing seven surveys in Peruvian waters. We then used species distribution models to predict occurrence and distribution using either data source alone, and both data sources combined. Results showed seasonal differences between estimates of occurrence and distribution when using data sources independently. Combining data resulted in more balanced insights into occurrence and distributions, and reduced uncertainty. Most notably, both species were predicted to occur in Peruvian waters during all four annual quarters: the northern Humboldt upwelling system for Salvin’s Albatross and northern continental shelf waters for Black Petrels. Our results highlighted that relying on a single data source may introduce biases into distribution estimates. Our tracking data might have contained ontological and/or colony-related biases (e.g. only breeding adults from one colony were tracked), while our survey data might have contained spatiotemporal biases (e.g. surveys were limited to waters <200 nm from the coast). We recommend combining data sources wherever possible to refine predictions of species distributions, which ultimately will improve fisheries bycatch management through better spatiotemporal understanding of risks.
... Polybrominated diphenyl ether has been shown to increase in the brain when animals are losing body fat (Sagerup et al., 2009). However, although plastic ingestion can be deleterious for an individual animal, it is currently difficult to say how much of an effect it has on species at a population level (Dehnhard et al., 2019;Dias et al., 2019). Therefore, this highlights the need for more research to better understand the overall level and extent of threat that plastic pollution poses to wildlife. ...
Full-text available
Monitoring plastic ingestion by marine wildlife is important for both characterizing the extent of plastic pollution in the environment and understanding its effect on species and ecosystems. Current methods to detect plastic in the digestive system of animals are slow and invasive, such that the number of animals that can be screened is limited. In this article, magnetic resonance imaging (MRI) is investigated as a possible technology to perform rapid, non-invasive detection of plastic ingestion. Standard MRI methods were able to directly measure one type of plastic in a fulmar stomach and another type was able to be indirectly detected. In addition to MRI, other standard nuclear magnetic resonance (NMR) measurements were made. Different types of plastic were tested, and distinctive NMR signal characteristics were found in common for each type, allowing them to be distinguished from one another. The NMR results indicate specialized MRI sequences could be used to directly image several types of plastic. Although current commercial MRI technology is not suitable for field use, existing single-sided MRI research systems could be adapted for use outside the laboratory and become an important tool for future monitoring of wild animals.
... those out of the continental shelf), up to 1200 km from the coast, where 12 seabird species breed (Mancini et al., 2016). Several of these species are threatened nationally (Ministério do Meio Ambiente, 2022), while migratory seabirds are threatened globally (Dias et al., 2019). Due to the environmental heterogeneity, massive freshwater systems, extensive coastal region, and wide latitudinal gradient, the Brazilian territory offers a variety of ecological opportunities for species with distinct environmental requirements. ...
Plastic pollution is an increasing global problem, especially in aquatic environments. From invertebrates to vertebrates, many aquatic species have been affected by plastic pollution worldwide. Waterbirds also interact with plastics, mainly by ingesting them or using them as nest material. Brazil has one of the largest aquatic environment areas, including the most extensive wetland (the Pantanal) and biggest river (the Amazon), and a ∼7500 km long coastline, which hosts a remarkable waterbird diversity with more than 200 species from 28 bird families. Here, we synthesise published and grey literature to assess where, how, and which waterbirds (marine and continental) interact with plastics in Brazil. We found 96 documents reporting interaction between waterbirds and plastics. Only 32% of the occurring species in the country had at least one individual analysed. Plastic ingestion was reported in 67% of the studies, and seabirds were the study subject in 79% of them. We found no reports in continental aquatic environments, unveiling entire regions without any information regarding interactions. Consequently, this geographic bias drew a considerable taxonomic bias, with whole families and orders without information. Additionally, most studies did not aim to search for plastic interactions, which had a twofold effect. First, studies did not report their findings using the proposed standard metric, hampering thus advances in understanding trends or defining robust baselines. Second, as it was not their main objective, plastics were not mentioned in titles, abstracts, and keywords, making it difficult to find these studies. We propose means for achieving a better understanding of waterbird-plastic interactions in space and time, and recommend searching for sentinel species and for allocating research grants.
... Yet this substantial, natural role of seabirds as regional nutrient pumps is often impacted directly or indirectly through the activities of humans (Polis et al., 1997; B. NATURAL PROCESSES ON ISLANDS CONNECT TO THE MARINE ENVIRONMENT et al., 2018). Seabirds are the most threatened of all bird groups and their numbers have been decimated globally due to invasive species introduced to their breeding colonies, fisheries bycatch, pollution, and other threats (Paleczny et al., 2015, Dias et al., 2019. Linkages between land and sea are not wholly mediated by biology. ...
... Several threats are affecting marine bird populations globally, including contaminants, such as trace elements (Dias et al., 2019). The Arctic is a sink for global anthropogenic pollutants (AMAP, 2004), and long-term monitoring of marine biota across the circumpolar Arctic has revealed changes in Arctic contamination over time and variations across space (Bianchini et al., 2021;Rigét et al., 2004Rigét et al., , 2019. ...
Cadmium (Cd) is a trace element of toxicological concern that has been monitored in marine birds inhabiting the Canadian Arctic since 1975. Despite nearly 50 years of monitoring, research to date has largely evaluated single species, locations, or time points, and there is as of yet no holistic overview that jointly considers all available Cd data. We addressed this information gap by combining and analyzing most of the existing data on hepatic Cd concentrations in marine birds from the Canadian Arctic. Using data collected between 1975 and 2018 from eight seabird species from 12 Arctic breeding colonies, we examined temporal, spatial, and interspecific variation in hepatic Cd levels, and we evaluated possible drivers of marine bird Cd loads. Hepatic Cd concentrations ranged from 1.6 to 124 μg/g dry weight across species, and were highest in thick-billed murres (Uria lomvia) and king eiders (Somateria spectabilis), and lowest in black guillemots (Cepphus grylle), black-legged kittiwakes (Rissa tridactyla), and long-tailed ducks (Clangula hyemalis). All sites with multiple years of data showed interannual fluctuations in Cd, which were correlated with the North Atlantic Oscillation (NAO) index and with the previous year's June sea ice coverage, where marine birds exhibited higher Cd concentrations in positive NAO years and following years with lower sea ice coverage. Climate change is likely to shift the NAO to being more negative and to reduce sea ice coverage, and our results thus identify various ways by which climate change could alter Cd concentrations in marine birds in the Canadian Arctic. Understanding variations in marine bird contaminant burdens, and how these may be alters by other stressors such as climate change, is important for long-term marine bird conservation efforts.
Speciation is a continuous and complex process shaped by the interaction of numerous evolutionary forces. Despite the continuous nature of the speciation process, the implementation of conservation policies relies on the delimitation of species and evolutionary significant units (ESUs). Puffinus shearwaters are globally distributed and threatened pelagic seabirds. Due to remarkable morphological status the group has been under intense taxonomic debate for the past three decades. Here, we use double digest Restriction-Site Associated DNA sequencing (ddRAD-Seq) to genotype species and subspecies of North Atlantic and Mediterranean Puffinus shearwaters across their entire geographical range. We assess the phylogenetic relationships and population structure among and within the group, evaluate species boundaries, and characterise the genomic landscape of divergence. We find that current taxonomies are not supported by genomic data and propose a more accurate taxonomy by integrating genomic information with other sources of evidence. Our results show that several taxon pairs are at different stages of a speciation continuum. Our study emphasises the potential of genomic data to resolve taxonomic uncertainties, which can help to focus management actions on relevant taxa, even if they do not necessarily coincide with the taxonomic rank of species.
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Invasive alien species are a major threat to native insular species. Eradicating invasive mammals from islands is a feasible and proven approach to prevent biodiversity loss. We developed a conceptual framework to identify globally important islands for invasive mammal eradications to prevent imminent extinctions of highly threatened species using biogeo-graphic and technical factors, plus a novel approach to consider socio-political feasibility. We applied this framework using a comprehensive dataset describing the distribution of 1,184 highly threatened native vertebrate species (i.e. those listed as Critically Endangered or Endangered on the IUCN Red List) and 184 non-native mammals on 1,279 islands worldwide. Based on extinction risk, irreplaceability, severity of impact from invasive species, and technical feasibility of eradication, we identified and ranked 292 of the most important islands where eradicating invasive mammals would benefit highly threatened vertebrates. When socio-political feasibility was considered, we identified 169 of these islands where eradication planning or operation could be initiated by 2020 or 2030 and would improve the survival prospects of 9.4% of the Earth’s most highly threatened terrestrial insular vertebrates (111 of 1,184 species). Of these, 107 islands were in 34 countries and territories and could have eradication projects initiated by 2020. Concentrating efforts to eradicate invasive mammals on these 107 islands would benefit 151 populations of 80 highly threatened vertebrates and make a major contribution towards achieving global conservation targets adopted by the world’s nations. This is an open access article, free of all copyright, and may be freely reproduced, distributed, transmitted, modified, built upon, or otherwise used by anyone for any lawful purpose. The work is made available under the Creative Commons CC0 public domain dedication.
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Shearwaters and petrels (hereafter petrels) are highly adapted seabirds that occur across all the world’s oceans. Petrels are a threatened seabird group comprising 124 species. They have bet-hedging life histories typified by extended chick rearing periods, low fecundity, high adult survival, strong philopatry, monogamy and long-term mate fidelity and are thus vulnerable to change. Anthropogenic alterations on land and at sea have led to a poor conservation status of many petrels with 52 (42%) threatened species based on IUCN criteria and 65 (52%) suffering population declines. Some species are well-studied, even being used as bioindicators of ocean health, yet for others there are major knowledge gaps regarding their breeding grounds, migratory areas or other key aspects of their biology and ecology. We assembled 38 petrel conservation researchers to summarize information regarding the most important threats according to the IUCN Red List of threatened species to identify knowledge gaps that must be filled to improve conservation and management of petrels. We highlight research advances on the main threats for petrels (invasive species at breeding grounds, bycatch, overfishing, light pollution, climate change, and pollution). We propose an ambitious goal to reverse at least some of these six main threats, through active efforts such as restoring island habitats (e.g., invasive species removal, control and prevention), improving policies and regulations at global and regional levels, and engaging local communities in conservation efforts.
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The general decline of seabird populations worldwide raises large concerns. Although multiple factors are interacting to cause the observed trends, increased mortality from incidental bycatch in fisheries has proven to be important for many species. However, the bulk of published knowledge is derived from longline fisheries, whereas bycatch in gillnet fisheries is less studied and even overlooked in some areas. We present seabird bycatch data from a 10-year time-series of fishery data from the large fleet of small-vessels fishing with gillnets along the Norwegian coast—a large area and fishery with no prior estimates of seabird bycatch. In general, we document high rates of incidental bycatch (averaging 0.0023 seabirds/net, or approximately 0.08 seabirds/fishing trip). This results in an estimated annual bycatch between 1580 and 11500 (95% CI) birds in this fishery. There was a surprisingly high percentage (43%) of surface-feeding seabirds in the bycatch, with northern fulmar being the most common species. Among the diving seabirds caught, common guillemot was most numerous. Our findings suggest that coastal gillnet fisheries represent a more general threat to a wider range of seabird populations, as opposed to longline fisheries where surface-feeding seabird species seem to dominate the bycatch. The bycatch estimates for the Norwegian gillnet-fishery varied in time, between areas, and with fishing depth and distance from the coast, but we found no clear trends in relation to the type of gillnets used. The results enabled us to identify important spatio-temporal trends in the seabird bycatch, which can allow for the development and implementation of more specific mitigation measures. While specific time closures might be an efficient option to reduce bycatch for diving seabirds, measures such as gear modification and reduction in release of wastewater during fishing operation are probably a more effective mitigation approach for reducing bycatch of surface-feeding seabirds.
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Procellariiform seabirds are both the most threatened bird group globally, and the group with the highest incidence of marine debris ingestion. We examined the incidence and ecological factors associated with marine debris ingestion in Procellariiformes by examining seabirds collected at a global seabird hotspot, the Australasian - Southern Ocean boundary. We examined marine debris ingestion trends in 1734 individuals of 51 Procellariform species, finding significant variation in the incidence of marine debris abundance among species. Variation in the incidence of marine debris ingestion between species was influenced by the taxonomy, foraging ecology, diet, and foraging range overlaps with oceanic regions polluted with marine debris. Among the ecological drivers of marine debris ingestion variability in Procellariiformes, we demonstrate that the combination of taxonomy, foraging method, diet, and exposure to marine debris are the most important determinants of incidence of ingestion. We use these results to develop a global forecast for Procellariiform taxa at the risk of highest incidence of marine debris ingestion. We find seabirds that forage at the surface; especially by surface seizing, diving and filtering, those with a crustacean dominant diet, and those that forage in or near marine debris hotspots are at highest risk of debris ingestion. We predict that family with the highest risk are the storm petrels (Hydrobatidae and Oceanitidae). We demonstrate that the greater the exposure of high-risk groups to marine debris while foraging, the greater the incidence and number of marine debris items will be ingested.
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Although bycatch of seabirds and other long‐lived species is a critical conservation issue in world fisheries, case studies documenting significant reductions in the mortality of these low‐productivity species in a fishery are rare. We studied progress toward seabird conservation in the Alaskan longline fisheries, one of the largest and most diverse demersal fisheries. We generated annual seabird bycatch rates in 4 target fisheries and all fisheries combined from 23 years of fisheries observer data. We used 0‐inflated negative binomial models to evaluate variables influencing seabird bycatch per unit effort (BPUE) in 2 target fisheries. Following adoption of streamer lines, at first voluntarily and then mandatorily, seabird BPUE was reduced by 77‐ 90%, preventing mortality of thousands of birds per year. Despite this, BPUE increased significantly in 2 of 4 target fisheries since streamer lines were adopted. Although night setting yielded significant reductions (74‐97%) in seabird BPUE and significant increases (7‐11%) in fish catch per unit effort over daytime setting, nighttime setting increased the BPUE of Northern Fulmar (Fulmarus glacialis) by 40% and nontarget fish species by 5–17%. Thus, best practices to prevent seabird mortalities in longline fisheries varied by species assemblage and fishery. Our results inform global efforts toward fisheries bycatch reduction by illustrating that successful conservation requires fishery‐specific solutions, strong industry support, constant vigilance in analysis and reporting observer data, and ongoing outreach to fleets, especially to vessels with anomalously high BPUE. This article is protected by copyright. All rights reserved
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Fisheries transform marine ecosystems and compete with predators [1], but temporal trends in seabird-fishery competition had never been assessed on a worldwide scale. Using catch reconstructions [2] for all fisheries targeting taxa that are also seabird prey, we demonstrated that average annual fishery catch increased from 59 to 65 million metric tons between 1970-1989 and 1990-2010. For the same periods, we estimated that global annual seabird food consumption decreased from 70 to 57 million metric tons. Despite this decrease, we found sustained global seabird-fishery food competition between 1970-1989 and 1990-2010. Enhanced competition was identified in 48% of all areas, notably the Southern Ocean, Asian shelves, Mediterranean Sea, Norwegian Sea, and Californian coast. Fisheries generate severe constraints for seabird populations on a worldwide scale, and those need to be addressed urgently. Indeed, seabirds are the most threatened bird group, with a 70% community-level population decline across 1950-2010 [3].
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Negative effects of ecotourism on wildlife are rising worldwide. Conservation physiology can play a major role in protecting wildlife by providing early alerts on changes in the status of individuals exposed to tourist activities. We measured an integrated set of immune and health-state indices to evaluate the effects of ecotourism on Magellanic penguins (Spheniscus magellanicus). We studied two reproductive colonies that differed in the intensity of tourism and population trends: Punta Tombo (higher tourism intensity, declining population) and San Lorenzo (lower tourism intensity, growing population). Within each colony, we compared individuals from an area that was exposed to tourists and a control area where tourism was excluded. Adult penguins exposed to tourism at Punta Tombo, but not at San Lorenzo, showed physiological alterations indicative of chronic stress (higher heterophil to lymphocyte ratios) and parasitic infection (elevated heterophil and eosinophil counts). Penguin chicks exposed to tourism at Punta Tombo, but not at San Lorenzo, also showed physiological alterations indicative of poor immune and general-health condition: lower humoral innate immunity, haematocrit, and glucose levels and higher inflammatory responses likely due to increased prevalence of fleas. Our results indicate that individuals of a declining population exposed to high levels of tourism express physiological indicators of chronic stress and poor health that could make adults and juveniles vulnerable to disease. These effects are expressed despite a long history of exposure and behavioural habituation to human visitation. In contrast, individuals of a growing population exposed to more recent and lower levels of tourism showed no effect. Our study demonstrates how a diverse physiological toolkit within a conservation physiology approach can provide important information for a better comprehension of anthropogenic effects on wild animals in our changing world.
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Although evidence-based approaches have become commonplace for determining the success of conservation measures for the management of threatened taxa, there are no standard metrics for assessing progress in research or management. We developed 5 metrics to meet this need for threatened taxa and to quantify the need for further action and effective alleviation of threats. These metrics (research need, research achievement, management need, management achievement, and percent threat reduction) can be aggregated to examine trends for an individual taxon or for threats across multiple taxa. We tested the utility of these metrics by applying them to Australian threatened birds, which appears to be the first time that progress in research and management of threats has been assessed for all threatened taxa in a faunal group at a continental scale. Some research has been conducted on nearly three-quarters of known threats to taxa, and there is a clear understanding of how to alleviate nearly half of the threats with the highest impact. Some management has been attempted on nearly half the threats. Management outcomes ranged from successful trials to complete mitigation of the threat, including for one-third of high-impact threats. Progress in both research and management tended to be greater for taxa that were monitored or occurred on oceanic islands. Predation by cats had the highest potential threat score. However, there has been some success reducing the impact of cat predation, so climate change (particularly drought), now poses the greatest threat to Australian threatened birds. Our results demonstrate the potential for the proposed metrics to encapsulate the major trends in research and management of both threats and threatened taxa and provide a basis for international comparisons of evidence-based conservation science. © 2018 Society for Conservation Biology.
Knowing the spatial scales at which effective management can be implemented is fundamental for conservation planning. This is especially important for mobile species, which can be exposed to threats across large areas, but the space use requirements of different species can vary to an extent that might render some management approaches inefficient. Here the space use patterns of seabirds were examined to provide guidance on whether conservation management approaches should be tailored for taxonomic groups with different movement characteristics. Seabird tracking data were synthesised from 5419 adult breeding individuals of 52 species in ten families that were collected in the Atlantic Ocean basin between 1998 and 2017. Two key aspects of spatial distribution were quantified, namely how far seabirds ranged from their colony, and to what extent individuals from the same colony used the same areas at sea. There was evidence for substantial differences in patterns of space-use among the ten studied seabird families, indicating that several alternative conservation management approaches are needed. Several species exhibited large foraging ranges and little aggregation at sea, indicating that area-based conservation solutions would have to be extremely large to adequately protect such species. The results highlight that short-ranging and aggregating species such as cormorants, auks, some penguins, and gulls would benefit from conservation approaches at relatively small spatial scales during their breeding season. However, improved regulation of fisheries, bycatch, pollution and other threats over large spatial scales will be needed for wide-ranging and dispersed species such as albatrosses, petrels, storm petrels and frigatebirds.