David Duffy - Academia.edu (original) (raw)
Papers by David Duffy
Birdlife Conservation Series, 1994
The Peruvian coxtd pumo islands and headlands have been mong the world's best and worst mana... more 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 minrdforfrrtilizcrin thenineteenthcentury In theearly twen~ tmh century, with euano dcpasits exhausted and bird populations dmost exterminated by the exploiters, the Peruvian government nationalized the islmds and began to manage them ma sustvinablc resource. protecting the birds, imprwing their nesting i; ites. and taking only! he ...
When searching for prey, animals should maximize energetic gain, while minimizing energy expendit... more 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 plastic. Indeed, the highly vagile Laysan albatross (Phoebastria immutabilis) which forages throughout the North Pacific, are well known for their tendency to ingest plastic. Here we examine whether Laysan albatrosses nesting on Kure Atoll and Oahu Island, 2,150 km apart, experience different levels of plastic ingestion. Twenty two geolocators were deployed on breeding adults for up to two years. Regurgitated boluses of undigestable material were also collected from chicks at each site to compare the amount of plastic vs. natural foods. Chicks from Kure Atoll were fed almost ten times the amount of plastic compared to chicks from Oahu des...
Aquatic Conservation: Marine and Freshwater Ecosystems, 2020
Anthropocene, 2020
Abstract Biological and cultural diversity are integrally linked, yet understanding how culture i... more Abstract 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 Cymbidium orchids to Han Chinese traditional culture, this study sought to test how the decline of these populations related to four different orchid knowledge domains and various socio-demographic variables on the local scale. Interviews were conducted in eight villages in rural Liangshan Yi Autonomous Prefecture: four Han-majority and four Yi-majority. Using photographic-cue-cards of nine Cymbidium taxa, aggregate- and specific-knowledge were assessed of 15 randomly selected individuals per village (120 total), in three age groups. Results showed that species decline negatively impacted culturally important knowledge of orchids across all knowledge domains, regardless of pre-extinction orchid rarity, and regardless of socio-demographic variables. Following population collapse, the decline in perceived economic value of orchid knowledge outweighed the influence of cultural veneration that traditionally drove Cymbidium knowledge acquisition. These findings highlight how biodiversity loss not only negatively affects the ecology and environment, but also culture, with profound implications for cultural resilience and biocultural diversity conservation efforts.
Environmental Conservation, 2019
SummaryWith rapid urbanization worldwide, most people now live in cities, but the effects of urba... more SummaryWith 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 loss due to declining orchid populations. Participants in the Cymbidium trade were interviewed in three distinct urbanization-level jurisdictions in Sichuan, China: Puge (low urbanization), Huili (moderate urbanization) and Chengdu (high urbanization). Using photographic cue-cards of nine Cymbidium taxa, we assessed aggregate and specific knowledge held by 91 orchid collectors/traders across the urbanization gradient. Contrary to expectations, we found that urbanization and orchid knowledge were positively related, but this varied by knowledge type, with moderate urbanization showing significantly higher knowledge in two domains. Our...
Colonial Waterbirds, 1996
Colonial Waterbirds, 1995
Seabirds: feeding ecology and role in marine ecosystems, May 14, 1987
Estimates of the amounts of food consumed by seabirds are also essential where multi-species mana... more Estimates of the amounts of food consumed by seabirds are also essential where multi-species management is necessary, either because of legal or treaty requirements as in the California Current (Green, 1978) and the Southern Ocean (Mitchell & Sandbrook, 1980), or because a suite of
Pacific Conservation Biology, 2011
The islands of Pacific Oceania face unprecedented anthropogenic climate change within this centur... more 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 forests, and coastal wetlands. For the developed nations, an array of measures could ameliorate these effects. Developing nations, whose economies may be significantly damaged by climate change, face major impacts on their citizens, identifying conservation of biodiversity as a lesser priority. Conservation in these countries may not succeed unless the rich nations are willing to pay for preservation of biodiversity hotspots or where preservation of biodiversity satisfies the needs of local communities, often through traditional management and land tenure systems in rural areas. These communities will need useable information, as well as techn...
Marine ornithology, 2019
GOLDSTEIN, M.I., DUFFY, D.C., OEHLERS, S., CATTERSON, N., FREDERICK, J. & PYARE, S. 2019. Interse... more GOLDSTEIN, M.I., DUFFY, D.C., OEHLERS, S., CATTERSON, N., FREDERICK, J. & PYARE, S. 2019. Interseasonal movements and non-breeding locations of Aleutian Terns Onychoprion aleuticus. Marine Ornithology 47: 67–76. Few observations have been made of Aleutian Terns Onychoprion aleuticus outside of summer breeding colonies. We investigateed 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 breeding colony in North America (Yakutat, Alaska). We deployed 114 geolocator tags in 2010 and recovered six tags over the course of six years. Using light level data, we conducted spatial analysis of tern migration cycles from 2010 to 2013. Results revealed one of the longest distance terrestrial vertebrate migrations ever recorded, with a one-way migration distance of > 16 000 km between Alaska and the Southeast Asia/Oceania r...
Marine ornithology, 2014
Although the populations and ecologies of seabirds of the world’s larger upwelling ecosystems are... more Although the populations and ecologies of seabirds of the world’s larger upwelling ecosystems are relatively well studied (e.g. Murphy 1936, Duffy et al. 1987, Spear & Ainley 2008, Ainley & Hyrenbach 2009), comparatively little is known of the seabirds of many smaller upwelling ecosystems. This paper reports on inshore seabird distributions and numbers around the Santa Elena Peninsula in the Gulf of Papagayo, off northwestern Costa Rica, in relation to surface water temperature. We also present general observations on island breeding and roosting sites, as well as initial data on foraging.
Marine ornithology, 2014
The introduction of mammalian predators onto islands with terrestrially breeding seabirds can res... more The introduction of mammalian predators onto islands with terrestrially breeding seabirds can result in profoundly negative effects for breeding success and eventually for populations of the birds (e.g. Moors & Atkinson 1984). The preferred response is to remove such predators, and there are numerous successful examples (Towns et al. 1997, Nogales et al. 2004, Parkes et al. 2014). However, if complete predator removal is logistically impossible and complicated by the presence of multiple introduced predators, effective management may become more problematic. In such instances, knowledge of the relative damage contributed by each predator species may be helpful, so that limited resources can be directed at the species and management efforts that would be likely to have the greatest positive effect on seabirds and other native fauna.
g Of the nonprimate mammalian species with develping comparative gene maps, the feline gene map F... more g Of the nonprimate mammalian species with develping comparative gene maps, the feline gene map Felis catus, Order Carnivora, 2N 5 38) displays the ighest level of syntenic conservation with humans, ith as few as 10 translocation exchanges discriminatng the human and feline genome organization. To xtend this model, a genetic linkage map of microsatllite loci in the feline genome has been constructed ncluding 246 autosomal and 7 X-linked loci. Two hunred thirty-five dinucleotide (dC z dA)n z (dG z dT)n and 8 tetranucleotide repeat loci were identified and enotyped in a two-family, 108-member multigeneraion interspecies backcross pedigree between the doestic cat (F. catus) and the Asian leopard cat (Prioailurus bengalensis). Two hundred twenty-nine loci ere linked to at least one other marker with a lod core >3.0, identifying 34 linkage groups. Representaive markers from each linkage group were assigned o specific cat chromosomes by somatic cell hybrid nalysis, resulting in chromos...
Señor William Vogt, a la terminación del contracto de tres años que con autorización del Supremo ... more Señor William Vogt, a la terminación del contracto de tres años que con autorización del Supremo Gobierno celebrara con la Compañia, con el fin de que llevara a cabo estudios relativos a la mejor forma de protección de las aves guaneras y aumento de la produción de las aves guaneras. Boletín de la
Marine Ornithology 43: 133–134 (2015) Kleptoparasitism, or food piracy, is widespread among seabi... more Marine Ornithology 43: 133–134 (2015) Kleptoparasitism, or food piracy, is widespread among seabirds (Brockmann & Barnard 1979, Furness 1987), leading seabirds to adopt various strategies to avoid being parasitized. These include choice of nesting location (Nettleship 1972), changes in flight altitude and behavior when approaching the colony or nest site (Grant 1971), diving underwater to escape aerial pursuit (Grant 1971), avoiding situations in which the ratio of parasites is large relative to potential victims (Grant 1971, Blackburn et al. 2009) and decreasing the same ratio by defensively aggregating as flocks, as do other organisms (e.g. Hamilton 1971, Falconer 1976, Courchamp et al. 2002, Carbone et al. 2005). This note reports on the apparent use of the last strategy by Brown Boobies Sula leucogaster to avoid parasitism by Magnificent Frigatebirds Fregata magnificens. BROWN BOOBY SULA LEUCOGASTER GROUP SIZE AS A DEFENSE AGAINST KLEPTOPARASITISM
PLOS ONE
Millions of birds in the United States die annually due to vehicle collisions on roads. Collision... more 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 (Nē nē), which is endemic to Hawai'i. Using a nearly 40-year dataset of Nē nē road mortality in and around Hawai'i Volcanoes National Park, we sought to answer the following research questions: 1) has Nē nē mortality changed over time? 2) are there times of the year in which mortality is greatest and does it relate to specific events in the species' lifecycle? 3) does age at mortality differ over time, space, or sex? 4) given that existing mortalities appear to occur only in certain locations, do the number of mortality events differ across these locations; 5) does mortality rate show any density dependence? and, 6) are mortality rates related to numbers of visitors or vehicles? Between 1977 and 2014, a total of 92 Nē nē died from vehicle collisions; while absolute mortality increased over this time, the mortality rate remained the same. Similarly, average age of mortality increased over time, but did not differ by location or sex. Between 1995 and 2014, Nē nē population size and mortality rates were not correlated. Mortality was greatest in November and December (breeding season) and lowest in June. Most of the mortality occurred along just three stretches of road in and around the park, with the number of mortalities split about evenly inside and outside of the park. Furthermore, Nē nē mortality was unrelated to the number of visitors or traffic volume in the park. These findings suggest vehicle collisions are a growing concern for Nē nē , but that management actions to reduce mortality can be targeted at specific road segments and times of the year.
Birdlife Conservation Series, 1994
The Peruvian coxtd pumo islands and headlands have been mong the world's best and worst mana... more 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 minrdforfrrtilizcrin thenineteenthcentury In theearly twen~ tmh century, with euano dcpasits exhausted and bird populations dmost exterminated by the exploiters, the Peruvian government nationalized the islmds and began to manage them ma sustvinablc resource. protecting the birds, imprwing their nesting i; ites. and taking only! he ...
When searching for prey, animals should maximize energetic gain, while minimizing energy expendit... more 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 plastic. Indeed, the highly vagile Laysan albatross (Phoebastria immutabilis) which forages throughout the North Pacific, are well known for their tendency to ingest plastic. Here we examine whether Laysan albatrosses nesting on Kure Atoll and Oahu Island, 2,150 km apart, experience different levels of plastic ingestion. Twenty two geolocators were deployed on breeding adults for up to two years. Regurgitated boluses of undigestable material were also collected from chicks at each site to compare the amount of plastic vs. natural foods. Chicks from Kure Atoll were fed almost ten times the amount of plastic compared to chicks from Oahu des...
Aquatic Conservation: Marine and Freshwater Ecosystems, 2020
Anthropocene, 2020
Abstract Biological and cultural diversity are integrally linked, yet understanding how culture i... more Abstract 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 Cymbidium orchids to Han Chinese traditional culture, this study sought to test how the decline of these populations related to four different orchid knowledge domains and various socio-demographic variables on the local scale. Interviews were conducted in eight villages in rural Liangshan Yi Autonomous Prefecture: four Han-majority and four Yi-majority. Using photographic-cue-cards of nine Cymbidium taxa, aggregate- and specific-knowledge were assessed of 15 randomly selected individuals per village (120 total), in three age groups. Results showed that species decline negatively impacted culturally important knowledge of orchids across all knowledge domains, regardless of pre-extinction orchid rarity, and regardless of socio-demographic variables. Following population collapse, the decline in perceived economic value of orchid knowledge outweighed the influence of cultural veneration that traditionally drove Cymbidium knowledge acquisition. These findings highlight how biodiversity loss not only negatively affects the ecology and environment, but also culture, with profound implications for cultural resilience and biocultural diversity conservation efforts.
Environmental Conservation, 2019
SummaryWith rapid urbanization worldwide, most people now live in cities, but the effects of urba... more SummaryWith 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 loss due to declining orchid populations. Participants in the Cymbidium trade were interviewed in three distinct urbanization-level jurisdictions in Sichuan, China: Puge (low urbanization), Huili (moderate urbanization) and Chengdu (high urbanization). Using photographic cue-cards of nine Cymbidium taxa, we assessed aggregate and specific knowledge held by 91 orchid collectors/traders across the urbanization gradient. Contrary to expectations, we found that urbanization and orchid knowledge were positively related, but this varied by knowledge type, with moderate urbanization showing significantly higher knowledge in two domains. Our...
Colonial Waterbirds, 1996
Colonial Waterbirds, 1995
Seabirds: feeding ecology and role in marine ecosystems, May 14, 1987
Estimates of the amounts of food consumed by seabirds are also essential where multi-species mana... more Estimates of the amounts of food consumed by seabirds are also essential where multi-species management is necessary, either because of legal or treaty requirements as in the California Current (Green, 1978) and the Southern Ocean (Mitchell & Sandbrook, 1980), or because a suite of
Pacific Conservation Biology, 2011
The islands of Pacific Oceania face unprecedented anthropogenic climate change within this centur... more 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 forests, and coastal wetlands. For the developed nations, an array of measures could ameliorate these effects. Developing nations, whose economies may be significantly damaged by climate change, face major impacts on their citizens, identifying conservation of biodiversity as a lesser priority. Conservation in these countries may not succeed unless the rich nations are willing to pay for preservation of biodiversity hotspots or where preservation of biodiversity satisfies the needs of local communities, often through traditional management and land tenure systems in rural areas. These communities will need useable information, as well as techn...
Marine ornithology, 2019
GOLDSTEIN, M.I., DUFFY, D.C., OEHLERS, S., CATTERSON, N., FREDERICK, J. & PYARE, S. 2019. Interse... more GOLDSTEIN, M.I., DUFFY, D.C., OEHLERS, S., CATTERSON, N., FREDERICK, J. & PYARE, S. 2019. Interseasonal movements and non-breeding locations of Aleutian Terns Onychoprion aleuticus. Marine Ornithology 47: 67–76. Few observations have been made of Aleutian Terns Onychoprion aleuticus outside of summer breeding colonies. We investigateed 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 breeding colony in North America (Yakutat, Alaska). We deployed 114 geolocator tags in 2010 and recovered six tags over the course of six years. Using light level data, we conducted spatial analysis of tern migration cycles from 2010 to 2013. Results revealed one of the longest distance terrestrial vertebrate migrations ever recorded, with a one-way migration distance of > 16 000 km between Alaska and the Southeast Asia/Oceania r...
Marine ornithology, 2014
Although the populations and ecologies of seabirds of the world’s larger upwelling ecosystems are... more Although the populations and ecologies of seabirds of the world’s larger upwelling ecosystems are relatively well studied (e.g. Murphy 1936, Duffy et al. 1987, Spear & Ainley 2008, Ainley & Hyrenbach 2009), comparatively little is known of the seabirds of many smaller upwelling ecosystems. This paper reports on inshore seabird distributions and numbers around the Santa Elena Peninsula in the Gulf of Papagayo, off northwestern Costa Rica, in relation to surface water temperature. We also present general observations on island breeding and roosting sites, as well as initial data on foraging.
Marine ornithology, 2014
The introduction of mammalian predators onto islands with terrestrially breeding seabirds can res... more The introduction of mammalian predators onto islands with terrestrially breeding seabirds can result in profoundly negative effects for breeding success and eventually for populations of the birds (e.g. Moors & Atkinson 1984). The preferred response is to remove such predators, and there are numerous successful examples (Towns et al. 1997, Nogales et al. 2004, Parkes et al. 2014). However, if complete predator removal is logistically impossible and complicated by the presence of multiple introduced predators, effective management may become more problematic. In such instances, knowledge of the relative damage contributed by each predator species may be helpful, so that limited resources can be directed at the species and management efforts that would be likely to have the greatest positive effect on seabirds and other native fauna.
g Of the nonprimate mammalian species with develping comparative gene maps, the feline gene map F... more g Of the nonprimate mammalian species with develping comparative gene maps, the feline gene map Felis catus, Order Carnivora, 2N 5 38) displays the ighest level of syntenic conservation with humans, ith as few as 10 translocation exchanges discriminatng the human and feline genome organization. To xtend this model, a genetic linkage map of microsatllite loci in the feline genome has been constructed ncluding 246 autosomal and 7 X-linked loci. Two hunred thirty-five dinucleotide (dC z dA)n z (dG z dT)n and 8 tetranucleotide repeat loci were identified and enotyped in a two-family, 108-member multigeneraion interspecies backcross pedigree between the doestic cat (F. catus) and the Asian leopard cat (Prioailurus bengalensis). Two hundred twenty-nine loci ere linked to at least one other marker with a lod core >3.0, identifying 34 linkage groups. Representaive markers from each linkage group were assigned o specific cat chromosomes by somatic cell hybrid nalysis, resulting in chromos...
Señor William Vogt, a la terminación del contracto de tres años que con autorización del Supremo ... more Señor William Vogt, a la terminación del contracto de tres años que con autorización del Supremo Gobierno celebrara con la Compañia, con el fin de que llevara a cabo estudios relativos a la mejor forma de protección de las aves guaneras y aumento de la produción de las aves guaneras. Boletín de la
Marine Ornithology 43: 133–134 (2015) Kleptoparasitism, or food piracy, is widespread among seabi... more Marine Ornithology 43: 133–134 (2015) Kleptoparasitism, or food piracy, is widespread among seabirds (Brockmann & Barnard 1979, Furness 1987), leading seabirds to adopt various strategies to avoid being parasitized. These include choice of nesting location (Nettleship 1972), changes in flight altitude and behavior when approaching the colony or nest site (Grant 1971), diving underwater to escape aerial pursuit (Grant 1971), avoiding situations in which the ratio of parasites is large relative to potential victims (Grant 1971, Blackburn et al. 2009) and decreasing the same ratio by defensively aggregating as flocks, as do other organisms (e.g. Hamilton 1971, Falconer 1976, Courchamp et al. 2002, Carbone et al. 2005). This note reports on the apparent use of the last strategy by Brown Boobies Sula leucogaster to avoid parasitism by Magnificent Frigatebirds Fregata magnificens. BROWN BOOBY SULA LEUCOGASTER GROUP SIZE AS A DEFENSE AGAINST KLEPTOPARASITISM
PLOS ONE
Millions of birds in the United States die annually due to vehicle collisions on roads. Collision... more 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 (Nē nē), which is endemic to Hawai'i. Using a nearly 40-year dataset of Nē nē road mortality in and around Hawai'i Volcanoes National Park, we sought to answer the following research questions: 1) has Nē nē mortality changed over time? 2) are there times of the year in which mortality is greatest and does it relate to specific events in the species' lifecycle? 3) does age at mortality differ over time, space, or sex? 4) given that existing mortalities appear to occur only in certain locations, do the number of mortality events differ across these locations; 5) does mortality rate show any density dependence? and, 6) are mortality rates related to numbers of visitors or vehicles? Between 1977 and 2014, a total of 92 Nē nē died from vehicle collisions; while absolute mortality increased over this time, the mortality rate remained the same. Similarly, average age of mortality increased over time, but did not differ by location or sex. Between 1995 and 2014, Nē nē population size and mortality rates were not correlated. Mortality was greatest in November and December (breeding season) and lowest in June. Most of the mortality occurred along just three stretches of road in and around the park, with the number of mortalities split about evenly inside and outside of the park. Furthermore, Nē nē mortality was unrelated to the number of visitors or traffic volume in the park. These findings suggest vehicle collisions are a growing concern for Nē nē , but that management actions to reduce mortality can be targeted at specific road segments and times of the year.