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Recent changes on migratory behaviour of the White stork (Ciconia ciconia) in Portugal: towards the end of migration?

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Historically, the White stork (Ciconia ciconia) was almost entirely migratory in Europe, but recently increasing numbers of individuals started wintering in their Iberian breeding grounds. We performed a survey in 2015 to estimate the number of wintering storks in Portugal and assess the last two-decade trend based on results from seven previous surveys performed between 1995 and 2008. The number of wintering storks increased from 1,187 individuals in 1995 to 14,434 in 2015. Although the breeding population showed a considerable boost during the same period, the proportion of resident individuals increased substantially in the last two decades (from 18% to 62%), suggesting a sound change in the migratory behaviour of this species towards fully residency.
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Changes on the migratory behaviour of the White Stork
28
Recent changes on migratory behaviour of the
White stork (Ciconia ciconia) in Portugal:
Towards the end of migration?
Alterações recentes do comportamento
migratório da Cegonha-branca (Ciconia
ciconia) em Portugal: O fim da migração?
Inês Catry1,2,3*, Vítor Encarnação4, Carlos Pacheco5,
Teresa Catry6, Paulo Tenreiro7, Luís P. da Silva8,
Fernando L eão9, Filipe Bally10, Sara Roda10, Si lvério
Lopes11, Carlos Capela11, Hany Alonso2,12, Sérgio
Saldanha13, Otília Urbano13, Jorge Saraiva14, Paulo
Encarnação15, Nuno Sequeira16, Miguel Mendes17,
Paulo Monteiro18, Gonçalo Elias19 & Francisco
Moreira1,2
1 Centro de Ecologia Aplicada “Prof. B aeta Neves” & InBio – Rede de Investigação em Biodiversidade e Biologia Evolutiva, Instituto Sup erior
de Agronomia, Universidade de Lisboa, Tapada da Ajuda, 1349-017 Lisboa, Por tugal . 2 REN Biodiversity Chair, CIBIO/InBIO - Rede de
Investiga ção em Biodiversida de e Biologia Evolutiva, Uni versidade do Porto, Campus Agrári o de Vairão, 4485-601 Vairão, P ortugal. 3 School
of Environment al Sciences, University of East Anglia, Norwich, NR4 7TJ, United Kingdom. 4 Instituto da Conservação da Natureza e das
Floresta s, IP, Divisão de Conser vação da Biodiver sidade, Centro de Estud os de Migrações e Proteção de Aves, 2890 -015 Alcochete , Portugal.
5 Rua João de Freitas Branco, nº. 38 - 2º Dto. 1500-359 Lisboa. 6 Centro de E studos do Ambiente e do Mar (CESAM), Departamento de
Biologia Animal, Faculdade de Ciências da Univer sidade de Lisb oa, 1749-016 Lisboa, Portugal. 7 Rua 25 de Abril, 16 - 3020 575 Brasfemes,
Portugal. 8 Centro de Ciências do Mar e do Ambiente (MARE) e Centro de Ecologia Funcional (CEF), Departamento de Ciências da Vida,
Universidade de Coimbra, 3000-456 Coimbra, Por tugal. 9 Núcleo Regional de Aveiro da Quercus - A.N.C.N., Apartado 363, 3811-905 Aveiro,
Portugal. 10 Divisão de Ambiente, Município de Portimão, Largo 1º de Maio, 8500 -543 Portimã o, Portugal. 11 Instituto da Conservação da
Natureza e das Florestas, IP, Departamento de Conserva ção da Natureza e Florestas do Algarve, Parque Natural da Ria Form osa, Divisão
de Gestão Operacional e Fiscalização, CEAM, Quinta de Marim, Quelfes, CP - 8700-194 Olhão, Portugal. 12 CIBIO/InBio-UE, Centro de
Investiga ção em Biodiversid ade e Recursos Genéti cos, Pólo de Évora, Univ ersidade de Évora, Nú cleo da Mitra, Aparta do 94, 7002-554, Évora,
Portugal. 13 Quinta da Fonte, Caixa nº 4505, 6200 -065 Covilhã, Portugal. 14 Rua 26, Lote 533, Marquesa I, 2950 -680 Qta do Anjo, Palmela,
Portugal. 15 Estação Ornitológica Nacional Monte do Outeirão, Apartado 139, 7500-014 Vila Nova de Santo André, Portugal. 16 Quercus,
Centro Associativo do Calhau, Bairro do Calhau, 1500-045 Lisboa, Portugal. 17 Rua David Teixeira nº 226 2º Dto 8100 Loulé, Por tugal. 18
Instituto da Conservação da Natureza e das Florestas, IP, Reserva Natural do Sapal de Castro Marim e Vila Real de Santo António, Sapal de
Venta Moinhos , Apartado 7, 8951-909 Castro Marim , Portugal. 19 Apartado 19016, 1991-901 Lisboa, Portugal.
VOLUME 24 2016 | 2017
Historically, the White stork (Ciconia ciconia) was almost entirely migratory in Europe, but
recently increasing numbers of individuals started wintering in their Iberian breeding grounds. We
performed a survey in 2015 to estimate the number of wintering storks in Portugal and assess the
last two-decade trend based on results from seven previous surveys performed between 1995 and
2008. The number of wintering storks increased from 1,187 individuals in 1995 to 14,434 in 2015.
Although the breeding population showed a considerable boost during the same period, the pro-
portion of resident individuals increased substantially in the last two decades (from 18% to 62%),
suggesting a sound change in the migratory behaviour of this species towards fully residency.
ABSTRACT
* Corresponding author: inescatry@gmail.com
Keywords: census, migration, Portugal, wintering population, White Stork.
Changes on the migratory behaviour of the White Stork
29
Nas últimas décadas, um número crescente de Cegonhas-brancas (Ciconia ciconia) passa
o inverno na Península Ibérica, em vez de migrar para África. Em 2015 foi realizado um
censo nacional para determinar o número de indivíduos invernantes em Portugal e com-
parar com a tendência registada nas últimas duas décadas, baseado em sete censos realiza-
dos entre 1995 e 2008. O número de Cegonhas-brancas invernantes aumentou de 1,187
indivíduos em 1995 para 14,434 contabilizados em 2015. Embora este aumento seja em
parte justificado pelo aumento do efectivo reprodutor nas últimas duas décadas, a pro-
porção de indivíduos residentes aumentou substancialmente no mesmo período (de 18%
para 62%), sugerindo uma alteração no comportamento migratório da espécie que poderá,
no futuro próximo, tornar-se residente.
The migratory behaviour of birds is
changing in response to global environ-
mental change. Many migratory species
are modifying their migratory phenology
by advancing spring arrival to the breeding
areas (Cotton 2003, Jonzén et al. 2006),
shifting their breeding and wintering ranges
and shortening their migration distances by
wintering closer to the breeding grounds
(Visser et al. 2009, La Sorte & Jetz 2010).
In recent decades, even more profound and
fascinating changes to migratory behaviour
have occurred, with individuals from migra-
tory species abandoning migration com-
pletely (Newton 2008). In southern Europe,
particularly in the Iberian Peninsula, previ-
ously fully migratory species have recently
established non-migratory populations
(Berthold 2001, SEO/Birdlife 2012).
The iconic White stork (Ciconia ciconia)
is a very adaptable, opportunistic species.
After a sharp decline of the western Euro-
pean populations recorded in the mid-20th
century, likely due to the prolonged Suda-
no-Sahelian drought and locust control pro-
grams in this area (Dallinga & Schoenmak-
ers 1989), the Iberian population started to
recover in the mid-1980s. Increased food
availability and milder temperatures in
winter have enabled an increasing number
of residents, i.e., individuals that choose to
stay in Iberia rather than migrate to Africa.
Residency, coupled with changes in drought
conditions in the Sahel were thought to be
important in reversing the strong popula-
tion decline in Europe (Tortosa et al. 2002).
In Portugal, the recovery of the White stork
population also started in the mid-1980s.
The breeding population increased contin-
uously from 1,533 pairs in 1984 to 3,302
in 1994, 7,684 in 2004 and 11,691 in 2014
(Encarnação 2015). Although considered
traditionally a fully migratory species, some
authors refer the presence of small num-
bers of wintering storks in the rst half of
the 20th century and the existence of small
ocks during the decades of 1960 and 1970
(Tait 1924, Coverley c. 1945, Cary 1973).
This paper aimed at estimating the cur-
rent number of wintering storks in Portugal
and assessing the last two-decade trend of
resident storks based on results from seven
previous surveys performed between 1995
and 2008.
Introduction
RESUMO
Palavras-chave: Cegonha-branca, censo, migração, população invernante, Portugal.
Changes on the migratory behaviour of the White Stork
30
Methods
A program to monitor the number of winter-
ing white storks was launched in 1995, but the
last out of the seven census occurred in 2008
(Rosa et al. 2009). In 2015, between 5 and 10
October, we surveyed the wintering popula-
tion of white storks in Portugal to describe the
trend of the wintering population comparing
with data from seven previous surveys (1995
to 2008). The same survey was used to assess
the proportion of resident individuals, i.e., indi-
viduals that stay in Portugal all year-round.
After breeding, most migratory individuals
cross the Strait of Gibraltar towards their Afri-
can wintering grounds till the end of August
(Fernández-Cruz 2005). Migratory storks can
start their pre-nuptial migration very early,
but not before the end of October (Fundación
MIGRES, pers. comm.). From mid September
to mid November, the number of emigrants
and immigrants is residual (Rosa et al. 1998,
pers. obs.). Therefore, we considered the win-
tering birds counted during the survey period
as resident ones, although acknowledging that
these gures might be slightly overestimated by
the inclusion of birds from northern breeding
areas. Surveys included all areas where the spe-
cies is known to winter regularly, giving special
attention to areas with known high winter food
availability, such as landll sites and rice elds,
where the birds tend to concentrate (Figure 1).
1
2
35
67
8
129
4
10
11
1. Ria de Aveiro
2. Baixo Mondego
3. Vale do Tejo
4. Vale do Sorraia
5. Avis landll
6. Sado
7. Évora landll
8. Beja landll
9. Barlavento landll
10.Sotavento landll
11. Ria Formosa
12.Castro Marim
Figure 1 - Main wintering sites of white storks (Ciconia
ciconia) in Portugal surveyed between 1995 and 2015
(Rosa et al. 2009 and this study).
Figura 2 - Principais áreas de invernada de Cegonha-
branca (Ciconia ciconia) em Portugal entre 1995 e
2015 (Rosa et al. 2009 e presente estudo).
Changes on the migratory behaviour of the White Stork
31
Results
The number of wintering white storks in
Portugal has increased signicantly from
1,187 individuals in 1995 to 14,434 in
2015 (Table 1, Figure 2). Most birds con-
centrated in areas of rice elds (68%) and
landll sites (21%) where birds likely rely
on the guaranteed year-round food supply,
namely Red-swamp Craysh (Procambarus
clarkii) and anthropogenic food. The most
important areas for wintering storks were
the Tejo, Sorraia and Sado valleys holding
approximately 65% of the surveyed storks,
followed by Baixo Mondego and Ria de
Aveiro (12%) and the Algarve (8%; Table
1). The recorded northward range expan-
sion of breeding birds (Encarnação 2015)
seems to also occur during the non-breed-
ing period: the proportion of storks win-
Table 1 - Number of wintering white storks (Ciconia ciconia) counted in each surveyed area in Portugal between 1995 and
2015 (Rosa et al. 2009 and this study).
Tabela 1 - Efectivos de Cegonha-branca (Ciconia ciconia) contados em cada área de invernada em Portugal entre 1995 e 2015
(Rosa et al. 2009 e presente estudo).
1995 1996 1997 1998 1999 2006 2008 2015
Ria Aveiro nc 14 30 1 nc 79 163 422
Baixo Mondego 22 28 40 53 109 377 763 1342
Vale do Tejo 2 7 100 219 405 308 545 3339
Vale do Sorraia 9 31 19 67 nc 610 1145 1317
Avis Landll x x x x x 245 628 0
Évora Landll x x x x x 135 900 571
Sado 272 520 433 1368 2813 4238 3717 4792
Beja Landll x x x x x 873 1100 550
Sotavento
Landll 95 150 124 340 750 0 0 0
Barlavento
Landll x x x x x 585 800 790
Ria Formosa 168 156 197 52 37 30 10 106
Castro Marim 522 266 550 176 45 13 8 13
Other sites 97 253 215 149 42 450 241 1192
TOTA L 1187 1425 1708 2425 4201 7943 10020 14434
(nc) not counted, (x) landll site not built at survey date
Changes on the migratory behaviour of the White Stork
32
Number of storks
1187 1425 1708
2425
4201
7943
10020
14434
15000
10000
5000
0
1995 1996 1997 1998 1999 2006 2008 2015
Proportion of resident storks
18.0
1994/1995 2004/2006 2014/2015
51.6
61.7
100
80
60
40
20
0
Figure 2 - Population trend of wintering white storks (Ciconia ciconia) in Portugal between 1995 and 2015 (Rosa et al. 2009
and this study).
Figura 2 - Evolução do efectivo populacional invernante de Cegonha-branca (Ciconia ciconia) em Portugal entre 1995 e
2015 (Rosa et al. 2009 e presente estudo).
Figure 3 - Evolution of the White stork (Ciconia ciconia) resident population in Portugal in the last two decades as estimated
by the ratio between the number of breeding and wintering individuals. Breeding and wintering population were assessed in
the breeding season of 1994, 2004 e 2014 (n= 3302, 7684 and 11691 breeding pairs, respectively; Encarnação 2015) and
during winter surveys in 1995, 2006 (Rosa et al. 2009) and 2015 (this study).
Figura 3 - Evolução da população residente de Cegonha-branca (Ciconia ciconia) em Portugal nas últimas duas décadas,
estimada como a proporção entre o número de indivíduos reprodutores e o número de indivíduos migradores. As
estimativas da população reprodutora e invernante referem-se aos censos nacionais realizados nas primaveras de 1994,
2004 e 2014 (n= 3302, 7684 e 11691 casais reprodutores, respectivamente; Encarnação 2015) e aos censos de inverno
realizados em 1995, 2006 (Rosa et al. 2009) e 2015 (presente estudo).
Changes on the migratory behaviour of the White Stork
33
tering north of the Tejo River increased
from approximately 2% in 1995 to 14%
in 2015. Besides the high increase in the
number of wintering storks in coastal areas
in the centre of the country (Baixo Mon-
dego and Ria de Aveiro), we should high-
light the high number recorded in the Cas-
telo Branco district, where 200 birds were
counted at the Fundão landll site (included
in “other sites”, Table 1). Overall, although
the long-term positive trend in the number
of breeding birds could partially explain the
observed increase in the wintering popula-
tion numbers, our results unveil a change in
the migratory behaviour of white storks, as
the proportion of resident individuals in the
population steeply increased from 18% in
1994/1995 to 62% in 2014/2015 (Figure 3).
Discussion
Bird migratory behaviour can be highly
exible. Migration is likely to be advan-
tageous whenever there is sufcient envi-
ronmental variation to benet individu-
als that move to exploit spatial variation
in resource availability or quality (Boyle
2008, Newton 2008). Changes to envi-
ronmental conditions can thus alter the
selection pressures operating on migratory
behaviour. If winter conditions improve,
species may alter their migratory strategy
and stay closer to their breeding areas. This
saves them the costs of migration in terms
of time, energy and mortality and ensures
the benets of early arrival to the breed-
ing grounds (Visser et al. 2009). Climate
change may thus not only result in strong
shifts of phenology but also in changes in
the primary migratory decision (to migrate
or not migrate). A recent study showed
that rising winter temperatures in the last
decades have promoted an overall increase
in climatic similarity between the Iberian
Peninsula overwintering areas and African
wintering grounds of six bird species with
recent established overwintering popula-
tions in Iberia, including the White stork
(Correia 2014). Additionally, year-round
food availability from anthropogenic
sources, including rubbish dumps and land-
ll sites (Gilbert et al. 2016), and the intro-
duction of the invasive red-swamp craysh
in the 1970s (Ramos & Pereira 1981) likely
enabled the establishment of overwintering
populations of white storks in Iberia. In
Spain, national winter census performed in
1995 and 2004 showed a large increase in
the number of wintering storks, from 7,594
to 31,229 individuals (Molina & Del Moral
2005). Comparison with surveys of breed-
ing numbers (1994 and 2004, Molina &
Del Moral 2005) suggest an increase in the
resident Spanish population from 23% to
47%, matching well the ndings recorded
for Portuguese resident storks in the same
period (18% and 52%, respectively).
The migratory status of the White
stork is changing substantially and in
the mid-term, if environmental con-
ditions continue to favour non-mi-
gratory individuals, the population is
likely to change towards full residency.
Acknowledgements
Thanks are due to all volunteers that
participated in the census. We thank the
landll sites for their interest in our proj-
ect and for kindly permitting us to count
storks on their premises: Aterros Sani-
tários do Fundão (RESISTRELA), Coim-
bra e Aveiro (CITVRSU), Avis (VALNOR),
Palmela e Seixal (AMARSUL), Évora
(GESAMB), Vila Ruiva (AMCAL), Ermi-
das do Sado (AMBILITAL), Beja (RESI-
ALENTEJO), Barlavento e Sotavento
(ALGAR). IC (SFRH/BPD/102637/2014)
and LPS (SFRH/BD/77746/2011) bene-
ciated from post-doctoral and doctoral
grant from Fundação para a Ciência e
Tecnologia, respectively. We thank Rui
Lourenço and one anonymous referee
for helpful comments on the manuscript.
Changes on the migratory behaviour of the White Stork
34
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... Many studies document the use of landfills by different species of wild bird, as dumping sites and supplier markets are excellent areas for these species to feed easily [4][5][6].Moreover, the constant availability of food resources in cities and milder winter temperatures, due to climate change, allow certain wild species to make shorter migrations or even halt their migration to form resident populations as urban birds (UB) [7]. In Spain, gulls and storks are two examples of this situation [5,8,9]. ...
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Antimicrobial resistance (AMR) is one of the most important threats of the 21 st century. Wild birds have been described as reservoirs of AMR in different bacterial species, such as Salmonella spp. Privation of food, climate change and overpopulation have forced many wild species to modify their feeding habits, attending urban areas. In this context, the aim of this study was to study Salmonella presence, as well as related AMR in urban birds that inhabit the city and its surroundings. A total of 300 urban birds were sampled for Salmonella detection according to the ISO 6579-1:2017 (Annex D) recommendations, and serotyping was carried out according to the White-Kauffman-Le Minor scheme. Antimicrobial susceptibility was tested following 2013/652/EU Decision guides. Wild birds analysed were positive for Salmonella in 12.3 % of cases, with white storks fed in landfills as the most Salmonella prevalent species (p < 0.05). The most common serovars isolated were zoonotic (S. Enteritidis, S. Typhimurium and S. Typhimurium monophasic variant). From Salmonella isolated strains, 40.5 % were resistant to the most prevalent AMRs found in urban birds were ciprofloxacin (36.4 %), nalidixic acid (36.4 %) and colistin (27.3 %). The scientific community, public administration and population in general should work together to control antimicrobial administration and drug waste management in order to decrease the development and spread of AMR.
... In the past few decades, we have witnessed that white storks change their behavior as a response to human-caused alterations in their environmental surroundings, yet the future development of these behavioral changes is unclear. The number of white storks overwintering in Portugal has already increased tenfold in the last two decades (Catry et al., 2017). It has also been documented that an increasing number of individuals of the Spanish subpopulation use their nests all year round (Gilbert et al., 2016), suggesting an intensified competition among breeders. ...
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Human‐induced changes in the climate and environment that occur at an unprecedented speed are challenging the existence of migratory species. Faced with these new challenges, species with diverse and flexible migratory behaviors may suffer less from population decline, as they may be better at responding to these changes by altering their migratory behavior. At the individual level, variations in migratory behavior may lead to differences in fitness and subsequently influence the population's demographic dynamics. Using lifetime GPS bio‐logging data from 169 white storks (Ciconia ciconia), we explore whether the recently shortened migration distance of storks affects their survival during different stages of their juvenile life. We also explore how other variations in migratory decisions (i.e., time, destination), movement activity (measured using overall body dynamic acceleration), and early life conditions influence juvenile survival. We observed that their first autumn migration was the riskiest period for juvenile white storks. Individuals that migrated shorter distances and fledged earlier experienced lower mortality risks. In addition, higher movement activity and overwintering “closer‐to‐home” (with 84.21% of the tracked individuals stayed Europe or North Africa) were associated with higher survival. Our study shows how avian migrants can change life history decisions over only a few decades, and thus it helps us to understand and predict how migrants respond to the rapidly changing world.
... Паразитологическому анализу было подвергнуто 294 экземпляра рыб 13 видов, в том числе густеры ( Полученный материал обработан компрессорным методом с последующей микроскопией и фотофиксацией [1,2]. Определение видов паразитов проводилось по определителям [3,4]. ...
Conference Paper
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White Stork (Ciconia ciconia) investigations were conducted at 17 landfill sites for the first time in Belarus during 2016–2018. Birds were registered on all large and medium size (more than 7 ha) landfill sites in different regions of the country. Storks use that places for feeding or resting from early April to late August. At the end of breeding season, their numbers increase due to appearance of nonbreeding and young birds. The maximum number of birds was observed at Grodno (up to 400), Pinsk (200) and Berioza (68) landfill sites in western part of the country. In central Belarus maximal numbers were registered at Soligorsk (52) and Minsk (39 and 20) landfill sites. From 2 to 6 storks were observed on rubbish dumps in eastern Belarus.
Article
Anthropogenic structures are increasingly encroaching wildlife habitats, creating conflicts between humans and animals. Scaling up renewable energy requires new infrastructures such as power lines, that cause high mortality among birds since they act as obstacles to flight and are used for perching and nesting, which can result in collisions or electrocutions. These interactions often endanger wildlife populations and may also result in high financial costs for companies. Flight behaviour plays a crucial role in collision risk, and the study of flight altitudes enables us to understand what drives birds to fly at collision risk altitudes. This allows the identification of high-risk areas, conditions and bird behaviours, and the implementation of mitigation measures by power line companies. In this study, we use boosted random tree modelling to identify drivers of white stork (Ciconia ciconia) flight altitudes and to investigate the factors that lead them to fly at collision risk altitudes. We found that the main drivers of flight altitude for this soaring bird species were time of day, distance to the nearest landfill site and cloud cover density. Bird age, habitat type and season were comparatively less important. Collision risk increases during crepuscular hours near landfill sites, also in days with high cloud cover density and during the breeding season. In recent years, hundreds to thousands of storks congregate daily at landfill sites to take advantage of the predictability and superabundance of anthropogenic food waste. Some of these sites have high density of power lines, becoming collision risk hotspots for storks and other landfill users. Despite being susceptible to collision, our results suggest that white storks can avoid power lines to a certain extent, by changing their flight altitude at ca. 80 m from these structures. This study shows that the implementation of mitigation measures for existing power lines should be prioritized in areas in the vicinity of landfill sites within white stork distribution ranges, and the projection of new lines should avoid those areas. These measures would benefit species vulnerable to mortality due to power line collision, and it would also reduce associated power outages and economic costs.
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Spring and autumn migrations of the White Stork (Ciconia ciconia) in Ukraine in 2019. - V.N. Grishchenko. - Berkut. 28 (1-2). 2019. - The large data set about timing of White Stork migrations was obtained using Facebook and other sources in the Internet as well as own observations. In total, I have collected information about 342 first arrival dates, 49 dates of the start of autumn passage, 41 dates of the last departure for the whole country. Weekend bias was absent. I marked points of observations on the map that visually shows the course of arrival. First migrating storks were found already on 1 March (in Lviv and Khmelnitsky regions). Since 5 March the migration became regular. The arrival registered every day and number of observations steadily increased. The storks appeared earlier in West Ukraine and in the south of Odesa region but owing to the warm weather and the full absence of the snow cover and ice they were found also in many points of northern and eastern regions till the end of the first ten-day of March. In total, the period of White Stork arrival lasted in Ukraine in 2019 39 days (1.03 – 8.04). There were only one large migration wave with the maximum on 20 March. Variation of timing was small. The average date of arrival for the whole country was 20 March (20.4 ± 0.4 days, median: 20 March). It is the earliest one for the whole period of monitoring since 1992. The long-term average date for previous 27 years was 26 March. After the ending of arrival, the solitary migrating flocks were occurred till the first ten-day of May. Therefore, the whole spring migration lasted more than two months. Storks flew single, in small groups or in flocks up to 200 individuals. On average, observers registered during passage 18.8 ± 2.2 birds (n = 172). The autumn passage have started in late July, the mass migration began on 3 August. The average date was 10 August (10.0 ± 1.2; median: 10 August; range: 28 July – 3 September). It is earlier than the long-term mean date in 1992–2018 (17 August). The active passage continued during the whole August but since the second ten-day of the months observers began to register the departure of last birds in some points. Storks disappeared in mass during the third ten-day of August, till the end of the first ten-day of September the migration almost came to a stop. The separate small flocks were observed up to late September. The average date of last departure was 30 August (30.1 ± 1.7; median: 28 August; range: 12 August – 30 September). It is close to the long-term mean date for 27 years (2 September). I did not take into account the late records of separate sick and weak storks. Passing flocks during the autumn migration were considerably larger than in spring (46.8 ± 7.6; range: 1–500; n = 97). [Ukrainian].
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Limited quantitative data are available on food habits of the White Stork (Ciconia ciconia) in Mediterranean environments, particularly in ricefields where a relatively new food resource, the invasive Red Swamp Crayfish (Procambarus clarkii), is abundant. We studied the diet of the White Stork in a heterogeneous landscape (Central Portugal) in order to compare the importance of the Red Swamp Crayfish as a food resource in a dominant agricultural/ricefield area in relation to a predominant woodland/agricultural area. White Storks´diet was analysed spatially (two sites) and seasonally (winter, spring, summer) using pellets (n = 122) collected between December 2012 and July 2013. Overall, from 1570 prey items identified, crayfish was the second most frequent and abundant prey in the diet (frequency of occurrence, FO = 79.5%; numerical frequency , NF = 22.9%, respectively), only surpassed by coleopterans (FO = 94.3%; NF = 57.7%). However, in terms of consumed biomass (global PB) crayfish dominated the diet (PB = 44.0%), representing 1.8 times the consumed biomass of coleopterans (PB = 24.2%). Consumption of crayfish was higher in the site with highest abundance of ricefields (NF: 32.0% vs. 17.7%; PB: 51.3% vs. 38.4%). Although no significant seasonal variations were detected in terms of the number of crayfish consumed by storks, consumed crayfish biomass was significantly higher in summer in relation to other seasons. Our findings suggest that in Mediterranean heterogeneous areas the White Stork feeds upon a wide range of prey taxa though, when available, coleopterans along with Red Swamp Crayfish dominate the diet.
Article
Open landfills seem to be playing an increasing role as target feeding areas for several species, not only in their breeding areas or during the winter, but also during the migration period. Evaluating the extent to which landfill sites are used by migrants is crucial to understanding their role in driving stopover decisions during migration, and in the potential health risks linked to feeding on refuse. The aim of this study was to evaluate the role of two open landfills located just before (France) and after (Spain) the East-Atlantic flyway enters Iberia through the western Pyrenees as potentially important stopover sites for the White Stork populations moving along this route. Overall, we detected that these sites were used by storks that had been ringed from many western European breeding populations, mainly during the migration period, but also in winter. The mean distance between the storks’ breeding/ringing origin and the landfill sites increased from summer to winter, suggesting that storks breeding further away pass through Iberia later in the season, reflecting population-specific timing of migration. During the autumn migration period (August-September), the first encountered landfill in France was estimated to be used by ca 1200 storks, and the other in Spain by 4000 storks. Our study hence contributes to a better understanding of the current and potentially hazardous role played by landfill sites in White Stork ecology, which is essential in order to provide management recommendations, and to evaluate the consequences of proposed open landfill closures in Europe. This article is protected by copyright. All rights reserved.
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Background The migratory patterns of animals are changing in response to global environmental change with many species forming resident populations in areas where they were once migratory. The white stork (Ciconia ciconia) was wholly migratory in Europe but recently guaranteed, year-round food from landfill sites has facilitated the establishment of resident populations in Iberia. In this study 17 resident white storks were fitted with GPS/GSM data loggers (including accelerometer) and tracked for 9.1 ± 3.7 months to quantify the extent and consistency of landfill attendance by individuals during the non-breeding and breeding seasons and to assess the influence of landfill use on daily distances travelled, percentage of GPS fixes spent foraging and non-landfill foraging ranges. Results Resident white storks used landfill more during non-breeding (20.1 % ± 2.3 of foraging GPS fixes) than during breeding (14.9 % ± 2.2). Landfill attendance declined with increasing distance between nest and landfill in both seasons. During non-breeding a large percentage of GPS fixes occurred on the nest throughout the day (27 % ± 3.0 of fixes) in the majority of tagged storks. This study provides first confirmation of year-round nest use by resident white storks. The percentage of GPS fixes on the nest was not influenced by the distance between nest and the landfill site. Storks travelled up to 48.2 km to visit landfills during non-breeding and a maximum of 28.1 km during breeding, notably further than previous estimates. Storks nesting close to landfill sites used landfill more and had smaller foraging ranges in non-landfill habitat indicating higher reliance on landfill. The majority of non-landfill foraging occurred around the nest and long distance trips were made specifically to visit landfill. Conclusions The continuous availability of food resources on landfill has facilitated year-round nest use in white storks and is influencing their home ranges and movement behaviour. White storks rely on landfill sites for foraging especially during the non-breeding season when other food resources are scarcer and this artificial food supplementation probably facilitated the establishment of resident populations. The closure of landfills, as required by EU Landfill Directives, will likely cause dramatic impacts on white stork populations.
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Rubbish dumps provide an extra and constant food source for many birds. The White Stork (Ciconia ciconia) is one of the species that have taken advantage of these new foraging areas both during breeding season and during the winter. This study analyzes data collected in the Spanish province of Cordoba throughout five years between 1992 and 1998 on the biology and breeding success of the White Stork and the influence of rubbish dumps. Breeding success varied significantly between years and areas in two of the study years. A banding program from 1990 to 1998 resulted in 145 storks being marked as nestlings. Of these, 49 were resighted at least once by May 2001 (34% resighting rate) and 16 of these birds were resighted as breeders at a mean age of 2.87 years. 75% of them were breeding close to rubbish dumps. Fifteen birds were resighted during wintering time, of which twelve were at rubbish dumps.
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Birds are responding to recent climate change in a variety of ways including shifting their geographic ranges to cooler climates. There is evidence that northern-temperate birds have shifted their breeding and non-breeding ranges to higher latitudes, and tropical birds have shifted their breeding ranges to higher altitudes. There is further evidence these shifts have affected migration strategies and the composition and structure of communities. Projections based on correlative distributional models suggest many birds will experience substantial pressures under climate change, resulting in range contraction and shifts. Inherent limitations of correlative models, however, make it difficult to develop reliable projections and detailed inference. Incorporating a mechanistic perspective into species distribution models enriches the quality of model inferences but also severely narrows the taxonomic and geographic relevance. Mechanistic distributional models have seen increased applications, but so far primarily in ectotherms. We argue that further development of similar models in birds would complement existing empirical knowledge and theoretical projections. The considerable data already available on birds offer an exciting basis. In particular, information compiled on flight performance and thermal associations across life history stages could be linked to distributional limits and dispersal abilities, which could be used to develop more robust and detailed projections. Yet, only a broadening of taxonomic scale, specifically to appropriately represented tropical diversity, will allow for truly general inference and require the continued use of correlative approaches that may take on increasingly mechanistic components. The trade-off between detail and scale is likely to characterize the future of global change biodiversity research, and birds may be an excellent group to improve, integrate and geographically extend current approaches.
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There is mounting evidence that global climate change has extended growing seasons, changed distribution patterns, and altered the phenology of flowering, breeding, and migration. For migratory birds, the timing of arrival on breeding territories and over-wintering grounds is a key determinant of reproductive success, survivorship, and fitness. But we know little of the factors controlling earlier passage in long-distance migrants. Over the past 30 years in Oxfordshire, U.K., the average arrival and departure dates of 20 migrant bird species have both advanced by 8 days; consequently, the overall residence time in Oxfordshire has remained unchanged. The timing of arrival has advanced in relation to increasing winter temperatures in sub-Saharan Africa, whereas the timing of departure has advanced after elevated summer temperatures in Oxfordshire. This finding demonstrates that migratory phenology is quite likely to be affected by global climate change and links events in tropical winter quarters with those in temperate breeding areas.
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This book presents an up-to-date, detailed and thorough review of the most fascinating ecological findings of bird migration. It deals with all aspects of this absorbing subject, including the problems of navigation and vagrancy, the timing and physiological control of migration, the factors that limit their populations, and more. Author, Ian Newton, reveals the extraordinary adaptability of birds to the variable and changing conditions across the globe, including current climate change. This adventurous book places emphasis on ecological aspects, which have received only scant attention in previous publications. Overall, the book provides the most thorough and in-depth appraisal of current information available, with abundant tables, maps and diagrams, and many new insights. Written in a clear and readable style, this book appeals not only to migration researchers in the field and Ornithologists, but to anyone with an interest in this fascinating subject. * Hot ecological aspects include: various types of bird movements, including dispersal and nomadism, and how they relate to food supplies and other external conditions * Contains numerous tables, maps and diagrams, a glossary, and a bibliography of more than 2,700 references * Written by an active researcher with a distinguished career in avian ecology, including migration research.
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Global climate change has led to warmer winters in NW Europe, shortening the distance between suitable overwintering areas and the breeding areas of many bird species. Here we show that winter recovery distances have decreased over the past seven decades, for birds ringed during the breeding season in the Netherlands between 1932 and 2004. Of the 24 species included in the analysis, we found in 12 a significant decrease of the distance to the wintering site. Species from dry, open areas shortened their distance the most, species from wet, open areas the least, while woodland species fall in between the other two habitats. The decline in migration distance is likely due to climate change, as migration distances are negatively correlated with the Dutch temperatures in the winter of recovery. With a shorter migration distance, species should be better able to predict the onset of spring at their breeding sites and this could explain the stronger advancement of arrival date found in several short distance species relative to long-distance migrants.
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1. Partially migratory species provide opportunities to understand which ecological factors cause some animals to migrate when others remain resident year round. Partial migration in birds has been explained by the dominance, arrival-time, and body-size hypotheses. 2. Testing these hypotheses has proven difficult due to the similarities of the predictions they make in temperate-breeding long-distance migrants. In tropical altitudinal migrants, however, these hypotheses make different predictions regarding the sex, age, and condition of migrants and residents. 3. Among white-ruffed manakins in Costa Rica, young birds were not more likely to migrate (as predicted by the dominance hypothesis), nor were females more likely to migrate (as predicted by the arrival-time hypothesis). All condition-related variables interacted with sex, together explaining much of the variation in migratory behaviour. 4. I re-articulate the body-size hypothesis in the context of tropical altitudinal bird migration, focusing explicitly on how limited foraging opportunities and differences in individual condition affect fasting ability during torrential rains. Despite ample food, the smallest birds or those stressed by parasites or moult may risk starvation at breeding elevations due to a reduction in foraging time. These results highlight how intrinsic and extrinsic factors may interact to produce observed patterns of within- and among-species variation in migratory behaviour.
A guide to birds of Southern Portugal Effects of climate and land management changes on conservation of Mediterranean cork oak woodlands and their bird communities
  • R Cary
  • R A H Correia
Cary, R. 1973. A guide to birds of Southern Portugal. União Gráfica, Lisboa. Correia, R.A.H. 2014. Effects of climate and land management changes on conservation of Mediterranean cork oak woodlands and their bird communities. PhD Thesis. University of East Anglia, Norwich.