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Medical History And Post-Release Survival Of Rehabilitated California Brown Pelicans Pelecanus Occidentalis Californicus, 2009-2019, Rebecca S. Duerr, Deborah L. Jaques, Barton G. Selby, Julie S. Skoglund, Suzanne Kosina Jul 2025

Medical History And Post-Release Survival Of Rehabilitated California Brown Pelicans Pelecanus Occidentalis Californicus, 2009-2019, Rebecca S. Duerr, Deborah L. Jaques, Barton G. Selby, Julie S. Skoglund, Suzanne Kosina

Marine Ornithology

California Brown Pelicans Pelecanus occidentalis californicus rehabilitated in 2009–2019 were released with metal federal and blue plastic auxiliary leg bands. Resighting data were obtained from the US Geological Survey’s Bird Banding Laboratory, International Bird Rescue’s citizen science reporting forms, and non-breeding communal roost site surveys. Medical problems and demographic data were assessed in relation to whether birds were resighted, whether they were alive at the most recent resighting, and by longevity after release. The 1418 blue-banded individuals in the study were admitted for rehabilitation and released 1 465 times, and 49.9% were resighted at least once. At the most recent …

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Characterizing The Diet Of A Threatened Seabird, The Marbled Murrelet Brachyramphus Marmoratus, Using High-Throughput Sequencing, Emily D. Fountain, Paige J. Kulzer, Richard T. Golightly, James W. Rivers, Scott F. Pearson, Martin G. Raphael, Matthew G. Betts, S. Kim Nelson, Daniel D. Roby, Nicholas F. Kryshak, Stephanie Schneider, M. Zachariah Peery Jul 2025

Characterizing The Diet Of A Threatened Seabird, The Marbled Murrelet Brachyramphus Marmoratus, Using High-Throughput Sequencing, Emily D. Fountain, Paige J. Kulzer, Richard T. Golightly, James W. Rivers, Scott F. Pearson, Martin G. Raphael, Matthew G. Betts, S. Kim Nelson, Daniel D. Roby, Nicholas F. Kryshak, Stephanie Schneider, M. Zachariah Peery

Marine Ornithology

Understanding prey consumption patterns is critical to understanding the ways in which seabirds cope with a changing ocean. However, characterizing the dietary habitats of seabirds can be challenging. In this study, we investigated the diet of the Marbled Murrelet Brachyramphus marmoratus population that lives in waters off California, Oregon, and Washington, USA, using fecal DNA, custom metabarcoding, and high-throughput sequencing. Murrelets were captured at sea by dip-netting at night. Across this region, murrelets consumed highly diverse prey types including 17 fish species and 10 invertebrate species, in accord with previous work indicating the species’ forage on a wide range of …

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Stable Isotope-Determined Diets Of Black Oystercatchers Haematopus Bachmani In The Northern Gulf Of Alaska, Brooke Carney, David Tessler, Heather Coletti, Jeffrey M. Welker, Douglas Causey Jul 2025

Stable Isotope-Determined Diets Of Black Oystercatchers Haematopus Bachmani In The Northern Gulf Of Alaska, Brooke Carney, David Tessler, Heather Coletti, Jeffrey M. Welker, Douglas Causey

Marine Ornithology

Black Oystercatchers Haematopus bachmani (BLOY) feed on intertidal invertebrates along coasts of the northern Gulf of Alaska and elsewhere. Details of their feeding ecology have only been marginally delineated, however, and as population sizes are small and limited geographically, rapid ecological changes may alter their prey base, placing BLOY resiliency in jeopardy. We examined the diets of BLOYs occupying the coast at three sites in Southeast Alaska using stable isotope analysis of carbon (δ13C) and nitrogen (δ15N) to answer the following three questions: (1) what are the diet proportions of prey groups consumed at different locations along the northern Gulf …

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Flight Altitudes Of Chick-Rearing Rhinoceros Auklets Cerorhinca Monocerata Measured By Gps Logger, Jumpei Okado, Yutaka Watanuki Jul 2025

Flight Altitudes Of Chick-Rearing Rhinoceros Auklets Cerorhinca Monocerata Measured By Gps Logger, Jumpei Okado, Yutaka Watanuki

Marine Ornithology

Alcids generally fly at low altitudes (below 5 m) over the sea but may occasionally fly higher in certain areas, which may put them at risk of collision with turbine blades in offshore wind farms. We used GPS loggers to investigate the location and altitude of flying Rhinoceros Auklets Cerorhinca monocerata. They typically flew at low altitudes averaging < 1 m but flew higher (> 20 m) when returning the last 5–10 km to their colony, which was located at an elevation of 120–130 m above sea level. Thus, the region over which Rhinoceros Auklets fly highest may vary, depending on the location and elevation of their …

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Sighting Of A Beck's Petrel Pseudobulweria Becki And A Vanuatu Petrel Pterodroma [Cervicalis] Occulta In Remote Oceania, And The Process Of Identification, Robert L. Flood, Kirk Zufelt Jul 2025

Sighting Of A Beck's Petrel Pseudobulweria Becki And A Vanuatu Petrel Pterodroma [Cervicalis] Occulta In Remote Oceania, And The Process Of Identification, Robert L. Flood, Kirk Zufelt

Marine Ornithology

This note reports observations of a presumed Beck’s Petrel Pseudobulweria becki and a Vanuatu Petrel Pterodroma [cervicalis] occulta in April 2022, in the low latitudes of the North Pacific, north of Kiritimati, Republic of Kiribati. The sightings are significant because the ranges of both taxa are barely known and their conservation classifications are concerning. We explain the circumstances of each sighting and the process of identification, reflecting upon current identification criteria and our studies of Beck’s Petrel and Vanuatu Petrel at their breeding grounds. Discussion is illustrated with photographs of each bird and its cryptic confusion counterpart—the larger Tahiti Petrel …

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Increasing Use Of Artificial Nest Chambers By Seasonally Segregated Populations Of Band-Rumped Storm Petrels Hydrobates Castro At St Helena, South Atlantic Ocean, Annalea Beard, Robert J. Thomas, Elizabeth Clingham, Leeann Henry, Renata Medeiros, Steffen Oppel, Alison Small, Frank Hailer Jul 2025

Increasing Use Of Artificial Nest Chambers By Seasonally Segregated Populations Of Band-Rumped Storm Petrels Hydrobates Castro At St Helena, South Atlantic Ocean, Annalea Beard, Robert J. Thomas, Elizabeth Clingham, Leeann Henry, Renata Medeiros, Steffen Oppel, Alison Small, Frank Hailer

Marine Ornithology

Artificial nest chambers have become a common management tool for monitoring nocturnal burrow-nesting seabirds, although their utility varies among species and locations. The widespread Band-rumped Storm Petrel Hydrobates castro species complex potentially harbours a cryptic species endemic to the South Atlantic. Here we evaluate the installation of artificial nest chambers as a tool for long-term conservation and monitoring of this species, which breeds in two distinct seasons on St Helena. Based on six years of observational data, we analysed factors affecting occupancy, mate and chamber fidelity, and reproductive success to optimise nest chamber installation and to enhance future management. Occupancy …

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Apparent Survival Among Adult Leach's Storm Petrels Hydrobates Leucorhous On A Colony Managed For Predators In Nova Scotia, Canada, Sarah E. Gutowsky, Gregory J. Robertson, Anna M. Calvert, David A. Fifield, Robert A. Ronconi, Jennifer C. Rock Jul 2025

Apparent Survival Among Adult Leach's Storm Petrels Hydrobates Leucorhous On A Colony Managed For Predators In Nova Scotia, Canada, Sarah E. Gutowsky, Gregory J. Robertson, Anna M. Calvert, David A. Fifield, Robert A. Ronconi, Jennifer C. Rock

Marine Ornithology

Population declines of Leach’s Storm Petrels Hydrobates leucorhous in the western Atlantic have both led to the species’ recent assessment as Threatened in Canada and contributed to a Vulnerable designation by the IUCN. Limited information suggests low adult survival rates are an important contributing factor. Off eastern Nova Scotia, Canada, Country Island is managed for avian predators and mustelids to protect nesting endangered Roseate Terns Sterna dougallii. The island also hosts a colony of Leach’s Storm Petrels. In 2016, a capture-mark recapture program was initiated for storm petrels, from which we estimated apparent survival and recapture probabilities for 571 breeding …

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Disparate Decadal Trends In Kaua'i Seabird Populations: Possible Effects Of Resource Competition And Anthropogenic Impacts, David Ainley, Stephanie Schneider, Gregory Spencer Jul 2025

Disparate Decadal Trends In Kaua'i Seabird Populations: Possible Effects Of Resource Competition And Anthropogenic Impacts, David Ainley, Stephanie Schneider, Gregory Spencer

Marine Ornithology

Population trends of seabirds nesting on Kaua‘i in the Hawaiian Islands, USA, were assessed across four decades using data from the Save Our Shearwaters (SOS) program. Started in 1979, the SOS database was intended to track the incidence of attraction of Kaua‘i’s seabirds to artificial lights, but recovery rate data also became useful to index population trends. These data documented precipitous declines of Newell’s Shearwater Puffinus newelli through 2017. Here we expand on those efforts by including four additional species and consider data to 2018. All five species exhibited increasing trends during SOS’s first decade, coincidental with increasing human population, …

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When Ornithology Meets Ethnology And Archeology: The Birds Of The Bird-Cult At Rapa Nui (Easter Island) And Their Demise, Manuel Marín Jul 2025

When Ornithology Meets Ethnology And Archeology: The Birds Of The Bird-Cult At Rapa Nui (Easter Island) And Their Demise, Manuel Marín

Marine Ornithology

The disappearance of the bird species involved in the bird-cult of Rapa Nui (Easter Island) was examined. The cult was a contest in which the winner gathered the first seabird egg of the year from a near-shore islet, allowing the winner to become the Tangata Manu, or Birdman. This title provided a heightened status, bringing social and economic benefits and a way of being closer to their gods. Three seabird species were involved in the bird-cult: Great Frigatebird Fregata minor, Sooty Tern Onychoprion fuscatus, and the Spectacled Tern Onychoprion lunatus, none of which currently breed in the area. Rock art …

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The Potential Of Ecologists To Enhance Our Understanding Of Seabird Health, Melanie R. Wells, Annie Philips, Mary-Anne Lea, Scott Carver Jul 2025

The Potential Of Ecologists To Enhance Our Understanding Of Seabird Health, Melanie R. Wells, Annie Philips, Mary-Anne Lea, Scott Carver

Marine Ornithology

Ecologists play a pivotal role in the detection and investigation of population changes in seabirds and by doing so have significant potential to contribute to enhancing knowledge of seabird health. This review highlights key examples in the literature where ecologists have employed diligent passive health surveillance and/or undertaken targeted investigations of seabirds, strategies that have augmented our knowledge of seabird health at individual and population levels. Within the context of One Health, an integrated approach to perceiving and managing health, this review amalgamates veterinarian and ecology disciplines by summarising auxiliary metrics of clinical health that may be considered for incorporation …

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Breeding Parameters Of Yellow-Legged Gull Larus Michahellis In The Largest Moroccan Colony: Natural Versus Urban Nesting Sites, Siham Bellout, Moulay Abdeljalil Ait Baamrane, Mohamed Aourir Jul 2025

Breeding Parameters Of Yellow-Legged Gull Larus Michahellis In The Largest Moroccan Colony: Natural Versus Urban Nesting Sites, Siham Bellout, Moulay Abdeljalil Ait Baamrane, Mohamed Aourir

Marine Ornithology

We investigated the main differences in the breeding ecology of Yellow-legged Gulls Larus michahellis nesting in urban (city of Essaouira) and natural (Mogador Island) environments on the African Atlantic coast of west-central Morocco during the 2018 and 2019 breeding seasons. This Yellow-legged Gull population is the largest in the southern portion of this species’ range, making it excellent for research on the breeding biology of marginal populations. Over two years, we collected data on nest density, chronology, clutch size, egg dimensions, and hatching success from nests across the city and island. Results showed that nest density averaged 1.26 ± 1.03 …

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Nesting Distribution Of Masked Booby Sula Dactylatra At Trindade Island, Western South Atlantic Ocean, Victória R.F. Benemann, Leonardo D. Araújo, Arthur Z. Fabbris, Rosalinda C. Montone, Maria V. Petry Jul 2025

Nesting Distribution Of Masked Booby Sula Dactylatra At Trindade Island, Western South Atlantic Ocean, Victória R.F. Benemann, Leonardo D. Araújo, Arthur Z. Fabbris, Rosalinda C. Montone, Maria V. Petry

Marine Ornithology

The Masked Booby Sula dactylatra is a surface-nesting seabird that breeds on offshore islands across the tropical and subtropical oceans. On inaccessible rocky areas on Trindade Island, located about 1200 km from Espírito Santo, Brazil, the nesting of this species has been poorly studied. To model the species’ nesting habitat suitability at Trindade Island, we mapped active nests during the breeding seasons of 2017 and 2019, from October to November, using a hand-held Global Positioning System receiver and an Unmanned Aerial Vehicle. In order to identify key areas, we created nesting habitat suitability maps using seven different algorithms (Random Forest, …

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Digging In! Burrowing Penguins And Surface Predators, Laura X.L. Tan, Kasun B. Ekanayake, Wouter F.D. Van Dongen, Peter Dann, Duncan R. Sutherland, Michael A. Weston Jul 2025

Digging In! Burrowing Penguins And Surface Predators, Laura X.L. Tan, Kasun B. Ekanayake, Wouter F.D. Van Dongen, Peter Dann, Duncan R. Sutherland, Michael A. Weston

Marine Ornithology

A native Australian corvid, Little Raven Corvus mellori, has emerged as a dominant and problematic predator of an ecologically and economically important seabird, the Little Penguin Eudyptula minor. In 2013, ravens successfully preyed upon clutches/broods of the burrow-nesting penguin, especially those in shallower, more accessible burrows. Individual raven size might mediate which ravens attack penguins; smaller ravens may be able to enter burrows more easily; alternatively, larger ravens may be more capable of overcoming penguin parental defence. Here, we consider the predator-prey interactions to assess whether associations with burrow characteristics persisted and examine whether raven size mediated propensity to prey …

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Seabird Abundance And Distribution Off Western Iberian Waters Estimated Through Aerial Surveys, Hélder Araújo, Pedro Correia-Rodrigues, Jorge Bastos-Santos, Marisa Ferreira, Andreia T. Pereira, Jose Martinez-Cedeira, José Vingada, Catarina Eira Jul 2025

Seabird Abundance And Distribution Off Western Iberian Waters Estimated Through Aerial Surveys, Hélder Araújo, Pedro Correia-Rodrigues, Jorge Bastos-Santos, Marisa Ferreira, Andreia T. Pereira, Jose Martinez-Cedeira, José Vingada, Catarina Eira

Marine Ornithology

Western Iberian waters are important migratory flyways, stopover sites, and wintering areas for several of the world’s seabird species. To describe seabird species composition, distribution, and abundance in these waters, we performed six aerial surveys in September and/ or October of each year, 2010–2015, covering 74 840 km2. Using line-transect methodology, 27 396 seabird sightings from 17 taxonomic groups were recorded along 10496.3 nautical miles (19 433 km). Using the program “Distance,” annual and overall abundance estimates were obtained for nine taxonomic groups: Balearic Shearwater Puffinus mauretanicus, Great Shearwater Ardenna gravis, Cory’s Shearwater Calonectris borealis, shearwaters, Northern Gannet Morus bassanus, …

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Albatross And Petrel Interactions With An Artisanal Squid Fishery In Southern Peru During El Niño, 2015-2017, Cristian Moreno, Javier Quiñones Jul 2025

Albatross And Petrel Interactions With An Artisanal Squid Fishery In Southern Peru During El Niño, 2015-2017, Cristian Moreno, Javier Quiñones

Marine Ornithology

We report on the occurrence of albatrosses (Diomedeidae) and petrels (Procellariidae) associated with an artisanal small-scale fishery (SSF) for Humboldt Squid Dosidicus gigas in waters of southern Peru during El Niño 2015–2016 and coastal El Niño 2017. We deployed as observers on a number of fishing trips to assess seabird interactions. White-chinned Petrels Procellaria aequinoctialis and Waved Albatross Phoebastria irroata were the most abundant species observed, followed by Salvin’s Thalassarche salvini and Chatham T. eremita albatross, and Cape Petrels Daption capense. The majority of procellariid species (> 60% of total birds) visited while vessels were positioned over the continental slope. …

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Diagnosis Of Hypothermia In Seabirds From Coastal California, Nancy L. Anderson Jul 2025

Diagnosis Of Hypothermia In Seabirds From Coastal California, Nancy L. Anderson

Marine Ornithology

This study established cloacal temperature (TCl) cut-off values to diagnose hypothermia in near shore seabirds rescued along the coast of California. All birds died when TCl was < 38.2 °C. When Aechmophorus grebes were excluded, 100% died when TCl was < 38.4 °C. Mortality increased 2–3× when TCl was lower than receiver operating curve-determined criteria for diagnosing hypothermia based on attitude: < 38.8 °C for mixed species, < 39.1 °C for Common Murres Uria aalge, and < 38.2 °C for Aechmophorus grebes. Reductions in TCl as small as 1.0 °C had significant physiologic effects.

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Using Remote Video Technology To Study Environmental Factors Influencing Productivity Of Black-Legged Kittiwakes Rissa Tridactyla, Sarah A. Tanedo, Tuula E. Hollmén, John M. Maniscalco, Sadie E.G. Ulman Jul 2025

Using Remote Video Technology To Study Environmental Factors Influencing Productivity Of Black-Legged Kittiwakes Rissa Tridactyla, Sarah A. Tanedo, Tuula E. Hollmén, John M. Maniscalco, Sadie E.G. Ulman

Marine Ornithology

Monitoring seabirds and their responses to ecosystem change provides essential information for understanding the reasons behind any changes in productivity or populations. However, many species nest in remote locations, which poses logistical challenges for long-term studies. Remote cameras offer an opportunity to confront this issue. The Black-legged Kittiwake Rissa tridactyla (kittiwake) has been used as an indicator of changes in its environment and is a prime candidate for monitoring via remote cameras. To investigate the potential for camera application, we used a remote camera system to collect six years (2010–2015) of reproductive data from a sub-colony of kittiwakes in Resurrection …

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A Test Of Mechanisms Of Population Differentiation In Gannets (Morus Spp.) Using Comparative Phylogeography And Morphometrics, Victoria L. Friesen, Rebecca Brunt, James A. Morris-Pocock, Drew Sauve, Allan J. Baker, Timothy P. Birt, William S. Davidson, Kyle H. Elliott, William A. Montevecchi Jul 2025

A Test Of Mechanisms Of Population Differentiation In Gannets (Morus Spp.) Using Comparative Phylogeography And Morphometrics, Victoria L. Friesen, Rebecca Brunt, James A. Morris-Pocock, Drew Sauve, Allan J. Baker, Timothy P. Birt, William S. Davidson, Kyle H. Elliott, William A. Montevecchi

Marine Ornithology

The relative importance of gene flow, genetic drift, and natural selection in driving genetic divergence of local populations, as well as the factors that disrupt gene flow in natural populations, are uncertain. Comparative analyses enable us to test explicit hypotheses regarding the roles of these factors. Gannets (Morus spp.) include three morphologically and ecologically similar seabird species: the Cape Gannet M. capensis, which breeds in southern Africa; the Australasian Gannet M. serrator, which breeds in southeastern Australia and New Zealand; and the Northern Gannet M. bassanus, which breeds in the North Atlantic. We assessed the extent of differentiation in mitochondrial …

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Hatching Success Of Common Murres Uria Aalge Is Linked To The Number Of Neighbours And Resource Availability, Amy L. Irvine, Julia E. Gulka, Gail K. Davoren Jul 2025

Hatching Success Of Common Murres Uria Aalge Is Linked To The Number Of Neighbours And Resource Availability, Amy L. Irvine, Julia E. Gulka, Gail K. Davoren

Marine Ornithology

When breeding within densely populated colonies, seabirds benefit from increased offspring protection from predators, but intraspecific competition for resources may outweigh these benefits. We tested whether the number of breeding-site neighbours and days of predator presence influenced the breeding performance of Common Murres Uria aalge at two different-sized colonies off the northeastern Newfoundland coast: Cabot Island (10000 breeding pairs; < 10 km offshore) and Funk Island (500000 breeding pairs; ~60 km offshore). Gulls, the main predators of murre eggs/chicks, inhabit both islands in similar numbers. During July–August 2018, camera traps placed at topographically similar plots on each colony recorded breeding performance metrics (i.e., hatching, fledging, reproductive success), number of breeding-site neighbours, and daily presence of gulls. Hatching success was lower at Funk Island (64.7%) than Cabot Island (96.2%), but nearly all hatched chicks fledged at both colonies. Lower hatching success at Funk Island was due to higher egg abandonment and predation. It was also associated with fewer breeding-site neighbours, including non-brooding mates and non-breeders, along with higher gull presence (96.6% of all gull sightings at both colonies). Fewer neighbours at Funk Island may have resulted from mates and non-breeding murres spending more time at sea due to longer distances to predictable foraging sites and higher conspecific densities relative to Cabot Island. In turn, with fewer breeding-site neighbours at Funk Island, parents appeared less able to defend against or deter gull predation. Although Funk Island has special conservation status, protection of Cabot Island may also be important for the long-term conservation of murres in Newfoundland.

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Status And Monitoring Methods Of A Red-Tailed Tropicbird Colony On O'Ahu, Hawai'i, Eric A. Vanderwerf Jul 2025

Status And Monitoring Methods Of A Red-Tailed Tropicbird Colony On O'Ahu, Hawai'i, Eric A. Vanderwerf

Marine Ornithology

The Red-tailed Tropicbird Phaethon rubricauda is a widespread seabird that nests in the tropical Pacific and Indian oceans. Most the global population nests in the predator-free Northwestern Hawaiian Islands. In the southeastern Hawaiian Islands, non-native predators restrict the species to nesting on coastal cliffs and small islets. I monitored 734 Red-tailed Tropicbird nests near Ha¯lona Point on O‘ahu during 2005–2020, controlled non-native predators to protect nests (beginning in 2006), and developed tools to facilitate monitoring of the species in other areas. The colony increased in size in response to predator control, from 18 eggs laid in 2006 to 94 eggs …

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Morphometric Sex Determination Of Breeding Adult Royal Thalasseus Maximus And Sandwich Terns T. Sandvicensis In Louisiana, Megan Nepshinsky, Sabrina S. Taylor, Jeff S. Liechty, Ashlee K. Minor, Eva D. Windhoffer, Aaron R. Pierce Jul 2025

Morphometric Sex Determination Of Breeding Adult Royal Thalasseus Maximus And Sandwich Terns T. Sandvicensis In Louisiana, Megan Nepshinsky, Sabrina S. Taylor, Jeff S. Liechty, Ashlee K. Minor, Eva D. Windhoffer, Aaron R. Pierce

Marine Ornithology

Many seabirds have sex-specific traits, including survival, philopatry, behavior, and diet, information that is essential for effective conservation strategies. The difficulty of sexing monomorphic seabirds, however, has resulted in a lack of information on these important traits and an incomplete understanding of the ecology of many species. We used a polymerase chain reaction (PCR)-based sexing approach to determine if Royal Thalasseus maximus and Sandwich terns T. sandvicensis in Louisiana, USA can be accurately sexed using morphometrics. DNA samples and morphological measurements were obtained from Royal Terns (n = 106) and Sandwich Terns (n = 112) to accurately identify sex and …

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The Rarest Alcid: Status And History Of The Guadalupe Murrelet Synthliboramphus Hypoleucus At Isla Guadalupe, Mexico (1892-2007), Darrell L. Whitworth, Harry R. Carter, Eduardo Palacios, Josh S. Koepke, William R. Mciver, Christine D. Hamilton, Gerard J. Mcchesney, Franklin Gress Jul 2025

The Rarest Alcid: Status And History Of The Guadalupe Murrelet Synthliboramphus Hypoleucus At Isla Guadalupe, Mexico (1892-2007), Darrell L. Whitworth, Harry R. Carter, Eduardo Palacios, Josh S. Koepke, William R. Mciver, Christine D. Hamilton, Gerard J. Mcchesney, Franklin Gress

Marine Ornithology

The Guadalupe Murrelet (GUMU) Synthliboramphus hypoleucus is the rarest alcid in the world (< 5000 pairs), with regular breeding documented only at Islas Guadalupe (hereafter, “Guadalupe”) and San Benito off the west-central coast of Baja California, Mexico. GUMU were discovered at Guadalupe in 1892, but by then feral cats Felis catus had already devastated the population and limited most nesting to predator-free islets just offshore. Despite its status as the only major GUMU breeding island, the population at Guadalupe was never adequately surveyed during the 20th century. In March–April 2007, we used survey techniques developed specifically for Synthliboramphus murrelets to assess the status and distribution of GUMU at Guadalupe. We counted 1511 GUMU during spotlight surveys in waters around the island. GUMU were abundant near the islets, but they were also relatively numerous near suitable breeding habitats off the north and south coasts of Guadalupe proper. Searches on four islets yielded 93 nests, most at Islotes Zapato (66; 71%) and Morro Prieto (21; 23%), where scores of abandoned eggs indicated intense competition for nests. We found seven nests on Guadalupe proper, the first proof of breeding there since 1950, but we also found 68 carcasses that confirmed significant predation by cats and raptors. A spotlight survey correction factor yielded 2418 breeding pairs (95% confidence interval = 1662–4367) at Guadalupe and its islets, which accounted for ~90% of the world breeding population (1822–4789 pairs). About 1150–1750 pairs were estimated on Islotes Zapato and Morro Prieto in 1968, but comparable data were lacking to assess historical or recent changes in population size. Basic studies of GUMU biology have only recently been initiated and should be a continuing priority. Recent conservation actions have benefited the native biota of Guadalupe, but further measures, such as localized rodent control and robust biosecurity on the islets, should be considered to mitigate serious threats to the vulnerable GUMU population and other seabirds.

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Levels Of Predation At Two Leach's Storm Petrel Hydrobates Leucorhous Breeding Colonies, Rielle Hoeg, Dave Shutler, Ingrid L. Pollet Jul 2025

Levels Of Predation At Two Leach's Storm Petrel Hydrobates Leucorhous Breeding Colonies, Rielle Hoeg, Dave Shutler, Ingrid L. Pollet

Marine Ornithology

Seabirds are declining worldwide, and predation by introduced and endemic species is one threat that affects many of them. Leach’s Storm Petrel Hydrobates leucorhous (hereafter LHSP) populations are declining in a number of locations for reasons that are likely multicausal, and perhaps local or regional, but relative contributions of individual causes are poorly understood. To help understand causes, we quantified predation at two Nova Scotian LHSP breeding colonies that differ in predator management: no management occurs on Bon Portage (BP) Island, whereas management is used on Country Island (CI). Transects were monitored for evidence of predation approximately biweekly on BP …

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Estimating Streaked Shearwater Calonectris Leucomelas Abundance In The Republic Of Korea Using Automated Acoustic Recorders, Kirk A. Hart, Steffen Oppel, Grant R.W. Humphries, Andrew Blackburn, Ki-Baek Nam Jul 2025

Estimating Streaked Shearwater Calonectris Leucomelas Abundance In The Republic Of Korea Using Automated Acoustic Recorders, Kirk A. Hart, Steffen Oppel, Grant R.W. Humphries, Andrew Blackburn, Ki-Baek Nam

Marine Ornithology

Traditional methods to assess population size in seabirds are applicable only to species that nest in visible locations, leaving cryptic nocturnal, burrow-nesting seabirds underrepresented in typical long-term population monitoring programs. Alternative methods to count burrow-nesting birds, however, are extremely labor-intensive and therefore are applicable only to small and possibly unrepresentative areas, and may have negative effects on burrow-nesting populations. We suggest the use of automatic acoustic recorders as a possible survey technique to overcome logistic difficulties of research of seabirds on remote islands in the Republic of Korea, where funding for ecological research is extremely limited but where globally important …

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Underwater Behavior Of Christmas Shearwaters Puffinus Nativitatis From Kure Atoll, Ilana Nimz, Mark A. Renshaw, Matthew Iacchei, Eric Vanderwerf, Cynthia Vanderlip, Matthew Saunter, Naomi Worcester, K. David Hyrenbach Jul 2025

Underwater Behavior Of Christmas Shearwaters Puffinus Nativitatis From Kure Atoll, Ilana Nimz, Mark A. Renshaw, Matthew Iacchei, Eric Vanderwerf, Cynthia Vanderlip, Matthew Saunter, Naomi Worcester, K. David Hyrenbach

Marine Ornithology

The Christmas Shearwater Puffinus nativitatis is an aquatic, tropical shearwater. While individuals of this species are known to forage by pursuit plunging and diving, there are no published reports quantifying their sub-surface foraging behavior. We obtained diving information from eight chick-rearing Christmas Shearwaters on Kure Atoll during June–August 2017. Over the 33 days during which instruments were deployed, 1521 dives were recorded. Individual deployments lasted three to eight days and were independent of the maximum depths recorded. Individual maximum depths were 10.7–24.1 m, averaging 15.4 m. While the deepest and longest recorded dive reached 24.1 m and lasted 31 s, …

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Stable Isotope Analysis Of Multiple Tissues From Chick Carcasses Of Three Pygoscelid Penguins In Antarctica, Yanina A. Ciriani, Mariana A. Juáres, M. Mercedes Santos, Steven D. Emslie Jul 2025

Stable Isotope Analysis Of Multiple Tissues From Chick Carcasses Of Three Pygoscelid Penguins In Antarctica, Yanina A. Ciriani, Mariana A. Juáres, M. Mercedes Santos, Steven D. Emslie

Marine Ornithology

Many types of animal tissues are increasingly being used for stable isotope analysis, with their application dependent on the time frame they reflect and their availability for collection. Here, we investigated the isotopic values (δ13C and δ15N) of four tissues (feather, skin, toenail, and bone) collected from fledgling-period chick carcasses of three species of pygoscelid penguins to compare the variability and accuracy of the data among tissues. Samples were collected at 25 de Mayo/King George Island during the 2017/18 austral summer. Chick carcasses are commonly found at active penguin colonies, and “opportunistic sampling” can easily be performed without disturbing nesting …

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Number And Distribution Records Of Caspian Tern Hydroprogne Caspia In Indonesia, With Special Reference To Sumatra, Muhammad Iqbal, Yus Rusila Noor, Deni Mulyana, Henni Martini, Ferry Hasudungan, Iwan Febrianto, Fransisca Noni Tirtaningtyas, Arum Setiawan, Indra Yustian, Hilda Zulkifli Jul 2025

Number And Distribution Records Of Caspian Tern Hydroprogne Caspia In Indonesia, With Special Reference To Sumatra, Muhammad Iqbal, Yus Rusila Noor, Deni Mulyana, Henni Martini, Ferry Hasudungan, Iwan Febrianto, Fransisca Noni Tirtaningtyas, Arum Setiawan, Indra Yustian, Hilda Zulkifli

Marine Ornithology

We summarize all reports of Caspian Tern Hydroprogne caspia recorded in Indonesia, with particular focus on Sumatra (1983–2019). There were 29 records in total, which together indicate that the Caspian Tern is a regular visitor to Indonesia, in contrast to previous assumptions that it is rare. This species has been recorded during the non-breeding period (September to March in Indonesia, and August to April in Sumatra) in small numbers ranging from one to 40 birds. Many potential sites for this species, particularly along east coast of Sumatra, have still not been well explored. Additional search efforts will advance our knowledge …

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Trends In Density, Abundance, And Response To Storm Damage For Westland Petrels Procellaria Westlandica, 2007-2019, Susan M. Waugh, Christophe Barbraud, Karine Delord, Kate L.J. Simister, G. Barry Baker, Georgie K. Hedley, Kerry-Jayne Wilson, Douglas R.D. Rands Jul 2025

Trends In Density, Abundance, And Response To Storm Damage For Westland Petrels Procellaria Westlandica, 2007-2019, Susan M. Waugh, Christophe Barbraud, Karine Delord, Kate L.J. Simister, G. Barry Baker, Georgie K. Hedley, Kerry-Jayne Wilson, Douglas R.D. Rands

Marine Ornithology

The density and distribution of Westland Petrel burrows was assessed over a 12-year period (2007–2019). During that time, burrow density increased while occupancy remained stable, commensurate with an annual population growth rate of 1.022 (95% confidence interval: 0.971–1.076), as estimated using mark recapture data. From our surveys, we estimated a 2019 baseline population of ~6200 breeding pairs and a world population of 13 800–17600 individuals, covering around 95% of the population. Transects were conducted to establish the location and density of 17 petrel sub-colonies in rugged, untracked terrain in Paparoa National Park, West Coast, New Zealand. Major storms in 2014–2018 …

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Wedge-Tailed Shearwater Ardenna Pacifica Fallout Patterns Inform Targeted Management, Brooke Friswold, Keith Swindle, David Hyrenbach, Melissa R. Price Jul 2025

Wedge-Tailed Shearwater Ardenna Pacifica Fallout Patterns Inform Targeted Management, Brooke Friswold, Keith Swindle, David Hyrenbach, Melissa R. Price

Marine Ornithology

Seabird fledglings are often attracted to artificial, bright lights, leading to their grounding. This phenomenon is termed “fallout” and is associated with an increased risk of mortality from land-based threats. This study evaluated temporal trends and spatial factors, such as fallout clustering near lights and proximity to colonies, to inform targeted management actions. Standardized surveys were conducted from 2002 to 2010 for Wedge-tailed Shearwater Ardenna pacifica (WTSH) fallout on the island of O‘ahu, Hawai‘i, USA. First, yearly fallout counts along the transect showed a two-year cycle and identified 25 November as the date with the highest fallout across years. Second, …

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Seabird Migration At Cabo Carvoeiro (Peniche, Portugal) In Autumn 2015, Johan Elmberg, Erik Hirschfeld, Helder Cardoso, Rebecca Hessel Jul 2025

Seabird Migration At Cabo Carvoeiro (Peniche, Portugal) In Autumn 2015, Johan Elmberg, Erik Hirschfeld, Helder Cardoso, Rebecca Hessel

Marine Ornithology

Land-based counts at Cabo Carvoeiro (Peniche, Portugal), made between 15 August and 15 November 2015 (effort 90 d, 517 h), tallied 302469 birds, most of which (99.98%) were southbound. Although 65 species were observed, four species contributed to 91% of the total: 207608 Northern Gannet Morus bassanus, 32281 Cory’s Shearwater Calonectris borealis, 16086 Manx Shearwater Puffinus puffinus, and 15222 Balearic Shearwater Puffinus mauretanicus. Passage as a whole increased throughout the period, mainly due to a gradual intensification of Northern Gannet migration. More than 67 000 southbound procellariforms of 12 species were recorded, as were 6183 Stercorariidae of four species. Daily …

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