David Cameron Duffy

David Cameron Duffy
University of Hawaiʻi at Mānoa | UH Manoa · School of LIfe Sciences

Ph.D.

About

129
Publications
26,722
Reads
How we measure 'reads'
A 'read' is counted each time someone views a publication summary (such as the title, abstract, and list of authors), clicks on a figure, or views or downloads the full-text. Learn more
4,733
Citations
Citations since 2017
19 Research Items
1128 Citations
2017201820192020202120222023050100150200
2017201820192020202120222023050100150200
2017201820192020202120222023050100150200
2017201820192020202120222023050100150200
Introduction
I started research at age 16 at the Great Gull Island Project. I got my AB degree at Harvard and did my dissertation at Princeton with Henry Horn, John Terborgh, and Bob May as head of my committee. After Africa, Costa Rica, Alaska and Georgia with Frank Golley, I ended up in Hawaii as the Wilder Chair, with bureaucrats trying to swamp my research on terns, invasive and endangered species. But I persist
Additional affiliations
May 1998 - present
University of Hawaiʻi at Mānoa
Position
  • Professor (Full)
September 1975 - December 1980
Princeton University
Position
  • PhD Student

Publications

Publications (129)
Article
A simple energy-balance model, relating energetic requirements of fish schools to food production, was used to predict shoal sizes. Lower limits to school size are unlikely to be set by food but rather by predation. Upper limits depend on both food and school behavior, being greater for schools that break up to feed than for schools that remain con...
Article
Full-text available
Life history characteristics of many herbaceous understory plants suggest that such species recover slowly from major perturbations such as clear cutting. We examined herbaceous cover and richness in the understories of nine primary (“old-growth”) forests in the southern Appalachian Mountains and of nine comparable secondary forests, ranging in age...
Article
Full-text available
Nymphal Ixodes scapularis Say, the vector of Lyme borreliosis, was most common in forested areas across Shelter Island, Suffolk County, New York, and least common in xeric habitats such as beach and grassland. At the scale of individual house yards, nymphs were most common at wooded edges of property and least common on lawns. The abundance of tick...
Article
Full-text available
Lyme disease is a zoonosis transmitted by ticks and caused by the spirochete Borrelia burgdorferi sensu lato. Epidemiological and ecological investigations to date have focused on the terrestrial forms of Lyme disease. Here we show a significant role for seabirds in a global transmission cycle by demonstrating the presence of Lyme disease Borrelia...
Article
Full-text available
The past quarter century has seen an unprecedented increase in the number of new and emerging infectious diseases throughout the world, with serious implications for human and wildlife populations. We examined host persistence in the face of introduced vector-borne diseases in Hawaii, where introduced avian malaria and introduced vectors have had a...
Article
Full-text available
Free-roaming domestic cats (i.e., cats that are owned or unowned and are considered ‘at large’) are globally distributed non-native species that have marked impacts on biodiversity and human health. Despite clear scientific evidence of these impacts, free-roaming cats are either unmanaged or managed using scientifically unsupported and ineffective...
Article
Full-text available
• For Rapa Nui (Easter Island) and its largest islet, Motu Nui, the change of the species assemblage over time was analysed, and a trait‐based approach to evaluate the potential losses in seabird function across the past centuries was applied. At a finer scale, the seasonal changes in seabird species composition in the current seabird assemblage wa...
Article
Biological and cultural diversity are integrally linked, yet understanding how culture impacts biological extinction is limited. The orchid richness of Southwest China’s Sichuan Province is the second highest in China, but price speculation and overharvest have resulted in significant recent orchid population collapses. Due to the importance of Cym...
Article
With rapid urbanization worldwide, most people now live in cities, but the effects of urbanization on knowledge about the natural environment is not well studied. Due to the importance of Cymbidium to Chinese traditional culture, we tested how urbanization influences the distribution of orchid knowledge across various knowledge domains at risk of l...
Article
Full-text available
Few observations have been made of Aleutian Terns Onychoprion aleuticus outside of summer breeding colonies. We investigated the nonbreeding distribution of Aleutian Terns by collating published and unpublished records of observations during the migration and wintering periods, and by implementing a geolocator tracking study at the largest known br...
Article
Full-text available
Millions of birds in the United States die annually due to vehicle collisions on roads. Collisions may be of particular interest for species of conservation concern, such as the endangered Hawaiian goose (Nēnē), which is endemic to Hawai‘i. Using a nearly 40-year dataset of Nēnē road mortality in and around Hawai‘i Volcanoes National Park, we sough...
Data
Lepczyk et al. Nene vehicle collision data. (XLSX)
Article
Full-text available
The ongoing and often synergistic effects of habitat loss, invasive species, and climate change pose challenges for conservation and management as widespread species become greatly reduced, sometimes to a single small population. To address this problem, conservation biologists must consider using approaches like translocation to create new populat...
Article
Full-text available
The Nightingale Reed-Warbler (Acrocephalus hiwae), a critically endangered songbird, is the last remaining of four reed-warbler species that once inhabited the Mariana Islands. The most recent population estimate for the species is 2915-3742 individuals distributed over the islands of Saipan (n = 2742, 95% CI = 1686-3956) and Alamagan (n = 946, 95%...
Article
Full-text available
Fishing activities by humans can affect seabirds either directly, through death and drowning, or indirectly, through effects on prey of marine birds. Interactions are diverse, with outcomes that range from beneficial to deterimental for birds. Outcomes for humans are similarly diverse. Three different ratios- Horn ratio (dietary overlap), Evans rat...
Article
Full-text available
Evolution in the Hawaiian Islands has produced a unique avian assemblage. Unfortunately, many of these bird species are highly endangered or extinct. Despite numerous and increasing threats and great effort aimed at saving endemic birds, we lack basic science necessary for understanding many species of concern. One such species is the critically en...
Chapter
Full-text available
How species come to be established on islands and their consequent adaptations and evolution are subjects that lie at the heart of much of ecology and evolutionary and conservation biology. On islands, small populations, limited gene diversity and flow, and simpler ecosystems facilitate our understanding of how species arrive and then adapt and evo...
Article
Full-text available
Globally, a majority of people use plants as a primary source of healthcare and introduced plants are increasingly discussed as medicine. Protecting this resource for human health depends upon understanding which plants are used and how use patterns will change over time. The increasing use of introduced plants in local pharmacopoeia has been expla...
Data
Introduced medicinal plants with cultivation status. (PDF)
Data
Richness of native and introduced species by province. (PDF)
Data
Treatment target categories and search criteria. (PDF)
Article
Full-text available
The endangered Puaiohi (Myadestes palmeri) endemic to Kaua'i is the island's only remaining native thrush. Given its small population of ~500 birds, it is essential to understand conditions that affect the species' recruitment and survival. Previous observations of Puaiohi suggested that weather may influence nest success and productivity, but no s...
Article
Full-text available
The island of Kaua'i, Hawai'i has several remaining populations of endangered, endemic Hawaiian petrels (Pterodroma sandwichensis) and Newell's shearwaters (Puffinus newelli) that would be threatened by the presence of predatory mongooses (Herpestes javanicus). Despite over 200 putative sightings, 1 road-kill and 2 recent captures, it is not clear...
Technical Report
Full-text available
Seabirds are a conspicuous component of both marine and oceanic island terrestrial ecosystems and perform important functions. They are top predators and transfer nutrients from ocean to land (Ellis et al. 2006). Because seabirds exploit marine resources through a variety of feeding methods, they are important ecological indicators of marine enviro...
Article
Full-text available
The Gulf of Papagayo off the northwestern coast of Costa Rica is one of a series of upwelling localities along the coast of Central America. We surveyed its marine avifauna during the non-upwelling season in 1988, using transects at sea and inspection of islands for nesting birds. The most common species at sea was Black Tern Chlidonias nigra, alth...
Article
The miconia (Miconia calvescens) invasion of the East Maui Watershed (EMW) started from a single introduction over 40 yr ago, establishing a nascent patch network spread across 20,000 ha. In 2012, an accelerated intervention strategy was implemented utilizing the Herbicide Ballistic Technology (HBT) platform in a Hughes 500D helicopter to reduce ta...
Article
Full-text available
Understanding a species’ feeding ecology is important in understanding the impacts of disturbances to populations (e.g. pollution, declines in fisheries and climate change). Seabirds have been used as bioindicators of such disturbances, and their diets have been examined using stable isotopes throughout the Atlantic and Indian Ocean and more recent...
Article
Full-text available
Small Indian Mongooses Herpestes javanicus have until recently been absent from the island of Kaua’i, Hawai’i. In anticipation of required management, we examine evidence that mongooses may be a significantly more dangerous predator than cats Felis catus for burrowing seabirds, particularly the endangered Hawaiian Petrel Pterodroma sandwichensis an...
Article
Full-text available
Hawaiʻi, an archipelago of the most isolated inhabited islands on the planet, faces unique and extreme challenges to its biodiversity. We examined how the conservation community has responded to these challenges and how the responses have changed over time, using twenty years of abstracts from the Hawaiʻi Conservation Conference, a yearly gathering...
Article
Full-text available
We applaud McCarthy et al for their research addressing a critical issue in feral cat management. We concur that feral and free-roaming cats pose myriad problems for people and the environment. However, we believe that the authors overlooked several important factors when concluding that trap-vasectomy- hysterectomy-release (IVHR) "should be recomm...
Article
Full-text available
Arctic terns Sterna paradisaea are noted for their extraordinary migration between Arctic and sub-Arctic breeding grounds and Antarctic wintering areas. Until recently, few data existed to document this migration, and none existed for North Pacific breeders. In this study, we tracked 6 Alaskan Arctic terns tagged with combined light geolocation and...
Article
Full-text available
We assessed migration routes of Arctic Terns Sterna paradisaea breeding in Prince William Sound, Alaska, by deploying geolocator tags on 20 individuals in June 2007, recovering six upon their return in 2008 and 2009. The terns migrated south along the North and South American coastlines. As they neared the southern end of the Humboldt Current upwel...
Article
Full-text available
This article reviews the biology, ecological effects, and management of the domestic cat (Felis catus) in the Pacific basin. The cat is one of the most controversial invasive species in the Pacific region because of its complex relations with humans. At one extreme, well-fed domestic house pets are allowed outdoors where they may hunt native animal...
Article
Full-text available
We developed an epidemiological model of avian malaria (Plasmodium relictum) across an altitudinal gradient on the island of Hawaii that includes the dynamics of the host, vector, and parasite. This introduced mosquito-borne disease is hypothesized to have contributed to extinctions and major shifts in the altitudinal distribution of highly suscept...
Article
Full-text available
Supplementary information to: Non-natives: 141 scientists object Full list of co-signatories to a Correspondence published in Nature 475, 36 (2011); doi: 10.1038/475036a. Daniel Simberloff University of Tennessee, Knoxville, Tennessee, USA. dsimberloff@utk.edu Jake Alexander Institute of Integrative Biology, Zurich, Switzerland. Fred Allendorf Univ...
Article
Full-text available
The islands of Pacific Oceania face unprecedented anthropogenic climate change within this century. Rising sea levels, increasing ocean acidification, warming land and sea temperatures, increasing droughts, and changes in the frequency and intensity of storms are likely to reorder or destroy ecosystems such as coral reefs, mangrove and montane fore...
Article
Full-text available
Fossil evidence indicates that diverse and abundant seabird communities were once found in the main Hawaiian Islands. However, these seabird populations have severely decreased, or even disappeared, as a result of human disturbance, habitat loss and predation from introduced mammals. Today, the vast majority of Hawai'i's seabirds nest on low-lying...
Article
Full-text available
We outline a functional management model for the eradication of incipient populations of invasive species that avoids reliance on official governmental response. This model involves formation of informal multi-partner committees that utilise outside funding to achieve pest-management goals. We describe why such a system was needed in Hawaii, how it...
Article
Full-text available
When searching for prey, animals should maximize energetic gain, while minimizing energy expenditure by altering their movements relative to prey availability. However, with increasing amounts of marine debris, what once may have been 'optimal' foraging strategies for top marine predators, are leading to sub-optimal diets comprised in large part of...
Article
Full-text available
Many species of tropical seabirds rely on subsurface predators such as tuna and dol- phins to drive prey close to the ocean's surface. We observed seabird foraging events from fishing vessels around the island of Oahu, Hawaii, to determine the prevalence and relative importance of different subsurface predators to seabird foraging. Sixty-nine seabi...
Article
Tested the hypothesis that bird species feeding at shallower depths are likely to pirate from those feeding at greater depths because the victims of kleptoparasitism have food (mainly Engraulis ringens) available to them that is not available to shallow-diving pirates. -P.J.Jarvis
Article
Full-text available
On 29 November 2004, a male Po?ouli Melamprosops phaeosoma died of what was effectively old age while in captivity in Hawai?i. The only two other known birds of this species, both at least five years old, have not been seen since 2003 and the species is now presumed extinct (Anon. 2004). With the passing of the Po?ouli, it is appropriate to ask wha...
Article
Infectious diseases now threaten wildlife populations worldwide but population recovery following local extinction has rarely been observed. In such a case, do resistant individuals recolonize from a central remnant population, or do they spread from small, perhaps overlooked, populations of resistant individuals? Introduced avian malaria (Plasmodi...
Article
Full-text available
This study uses a spatially explicit microclimate/biophysical approach to examine the potential distribution of the Po'ouli on Maui to find either new habitats to search for existence or refine search efforts in previously occupied areas. We used specific physiological and behavioral ecology bird data, and Po'ouli morphological and spectral data ob...
Article
Full-text available
We assessed the degree to which Alaskan lands reflect the state's biodiversity by dividing the entire state into four categories of land protection ranging from highly protected to minimally protected in terms of potential for future development. We then compared the percentage of each ecoregion and plant-cover type in each land protection class. W...
Article
Full-text available
A better understanding of the whole Prince William Sound (PWS) food web and its dynamics was achieved by constructing a balanced trophic model using the Ecopath approach. The PWS model was a cohesive synthesis of the overall biotic community with a focus on energy flow structure, and response to perturbations, both natural and anthropogenic. Forty-...
Article
Full-text available
Humboldt Spheniscus humboldti and Magellanic S. magellanicus penguins exhibit a zone of sympatry along the west coast of South America. The authors examined aspects of their foraging ecologies at four sites (three in the zone of sympatry) along the Chilean coast between 29° and 53°S and found that inter-site differences were more pronounced than in...
Article
The ecological literature on eastern forest-floor herbs and data collected in the southern Appalachians in Tennessee and North Carolina suggest five possible ecological mechanisms for reducing or limiting alpha diversity of vernal herbs in logged stands, three of which may also account for the slow recovery of some herbaceous species: (1) logging r...
Article
A short note to conclude this special publication on the biology, conservation and management of the Double-crested Cormorant in North America. The major accomplishment has been to bring all sides of the cormorant issue together (biologists, fish farmers, managers) to review opinions and the evidence on problems related to cormorants and human acti...
Article
Full-text available
Observations of ten Red-billed Tropicbirds (Phaethon aethereus) engaging in courtship flights and landing on Isla Santa Catalina, Costa Rica, suggest the first known breeding location for Costa Rica.
Article
Full-text available
Two dead Aleutian Terns (Sterna aleutica) were found dead along river otter (Lutra canadensis) trails in a colony on an island in Sitkalidak Strait, Kodiak Island, Alaska. A review of the literature suggests river otter predation on seabirds in the northeastern Pacific is widespread and that "surplus killing" of more prey than can be consumed is a...
Article
Full-text available
Cormorants Phalacrocoracidae have a long history of conflict with fishermen and more recently with fish-farmers. Cormorant species tend to be opportunistic, adaptable, and highly attracted to concentrated food sources. At the population level, there is little evidence to suggest that cormorants seriously deplete commercial food sources, although at...
Article
This article introduces the special publication prepared for Colonial Waterbirds from the proceedings of the symposium ''The Double-crested Cormorant: Biology, Conservation and Management'' held as part of the Colonial Waterbird Society Annual Meeting at the University of Mississippi, Oxford, Mississippi, USA, 14-18 October 1992. The twenty-seven p...
Article
Full-text available
Marine bird populations interact with fisheries in a variety of ways, with diverse outcomes. Evaluation of these outcomes requires a means of comparison across cases, and a means of identifying the relative importance of concomitant processes at relevant space and time scales. We describe a general quantitative framework that permits comparison of...
Article
Full-text available
Nymphal Ixodes scapularis Say deer ticks were collected at 22 parks or other natural areas on Long Island, New York, to examine the relationship between tick populations and geographic position, size of area, presence of white-tailed deer, Odocoileus virginianus (Zimmerman), and numbers of human Lyme disease cases in adjacent communities. Nymphal t...
Article
Full-text available
Based on winter flagging experiments on Long Island, NY, adult Ixodes scapularis Say have an apparent threshold of questing activity at 4 degrees C. This threshold should be incorporated into public education efforts because the public may be at risk of contracting Lyme disease any time during the winter when temperatures exceed 4 degrees C.
Article
Full-text available
There are four species of Spheniscus penguins, all with distributions limited to the Southern Hemi-sphere. The Humboldt (Peruvian) Penguin (S. hum-boldti) is found on the west coast of South America in the cold, upwelled waters of the Humboldt Current (Stonehouse 1975). The Magellanic Penguin (S. magellanicus) occurs to the south of the Humboldt Pe...
Article
Full-text available
The Peruvian coxtd pumo islands and headlands have been mong the world's best and worst managed of seabird nesting area?. The islands contained enormous dcoosm of seabird excreta or aumo which wm minrd - forfrrtilizcrin thenineteenthcentury In theearly twen~ tmh century, with euano dcpasits exhausted and bird populations dmost exterminated by the e...
Article
The long-term conservation of seabirds requires that we identify and protect globally significant seabird breeding and foraging sites. This paper proposes a revised classification of seabird breeding sites that distinguishes between significance at the national, regional, and international levels. It also discusses the information required for such...
Article
The risk for human infection with Lyme disease appears linked to the abundance of infected vector ticks, principally Ixodes dammini Spielman, Clifford, Piesman & Corwin, in the eastern United States. Habitat destruction by burning, although not well studied, has long been considered as an effective alternative to synthetic insecticides as a means o...
Article
Our paper (Duffy & Meier 1992) was an elfort to mea. sure the recovery of Appalachian forests understory herbs following deforestation. We expected herbal re- covery to parallel that of the trees, but our results showed a dramatic difference between primary and sec- ondary forests in the extent of herbaceous cover and species richness. Over time, t...
Chapter
Full-text available
The 280 species of seabirds occupy all the world’s oceans from polar leads to tropical blue-water, so their management and research needs vary greatly. On the other hand, they share certain characteristics that tend to make them vulnerable to human activity. They are long-lived and reproduce slowly; they tend to breed in large numbers on predator-f...
Article
Full-text available
Examines two hypotheses: 1) ants are present in all but the most hostile terrains and densest colonies of seabirds; and 2) when ants are present, their predatory activity normally prevents massive tick infestations, allowing seabirds to reproduce at permanent nests and colonies. Evidence is presented from several field sites in initial support of t...
Article
Full-text available
The 1982-1984 El Niño and associated events affected seabirds in the Pacific and Atlantic oceans. Effects ranged from extralimital dispersal to nest desertion and adult mortality, and appeared most severe in the eastern Pacific upwellings off Peru and California, and in the central Pacific. Up to 85% of seabirds died in Peru. In contrast, effects w...
Article
Guidelines for submitting commentsPolicy: Comments that contribute to the discussion of the article will be posted within approximately three business days. We do not accept anonymous comments. Please include your email address; the address will not be displayed in the posted comment. Cell Press Editors will screen the comments to ensure that they...
Article
Full-text available
Humboldt Penguins diving in clear water in Chile had two distinct behaviours; short dives ([`(x)] = 13.3 s)(\bar x = 13.3 s) where the birds remained within a metre of the surface and bounce dives, where the penguins descended the water column to the sea bed where they immediately returned to the surface. Here, dive time was correlated with water d...
Article
Full-text available
Foraging of seabirds in the Benguela upwelling ecosystem off southern Africa was examined to determine if species showed the same characteristics as those in a similar upwelling off Peru. In both areas, most foraging occurred in aggregations which varied in size and species composition in apparent response to size, depth, and duration of prey avail...
Article
Full-text available
Analysis of the historical record shows that reductions in guano