D. Cisneros-Heredia, Mirjaya Izurieta, Emilia Peñaherrera, M. Musschenga
Abstract. We review the distribution of White-cheeked Pintail (Anas bahamensis rubrirostris) in mainland Ecuador and show that the species has expanded its range significantly. Contrary to published records, A. b. rubrirostris has been present in mainland Ecuador at least since the early 20th century, although probably in low numbers. During the 20th century, the species increased its range along the entire coastlands of Ecuador and has reached the coasts of Colombia. The species has also extended its presence along the Andes, and we report the first breeding records of A. b. rubrirostris in the Andes at altitudes between 2360–2440 m, the highest across the entire range of the species. Additionally, we describe the transitioning plumage between ducklings and juveniles, which has not been portrayed in detail before.
摘要我们回顾了白颊斑尾鱼(Anas bahamensis rubrirostris)在厄瓜多尔大陆的分布，并表明该物种的分布范围已显著扩大。与已发表的记录相反，至少从20世纪初开始，A. b. rubrirostris就在厄瓜多尔大陆存在，尽管数量可能很低。在20世纪，该物种沿着厄瓜多尔的整个沿海地区扩大了其活动范围，并已到达哥伦比亚海岸。该物种还沿着安第斯山脉扩展了其存在，我们报告了在安第斯山脉海拔2360-2440米之间的海拔高度，该物种整个范围的最高海拔高度，A. b. rubrirostris的第一次繁殖记录。此外，我们还描述了雏鸭和幼鸭之间的过渡羽毛，这在以前没有详细描述过。
{"title":"Range Expansion and Breeding of White-Cheeked Pintail (Anas bahamensis) in the High Andes","authors":"D. Cisneros-Heredia, Mirjaya Izurieta, Emilia Peñaherrera, M. Musschenga","doi":"10.1675/063.045.0213","DOIUrl":"https://doi.org/10.1675/063.045.0213","url":null,"abstract":"Abstract. We review the distribution of White-cheeked Pintail (Anas bahamensis rubrirostris) in mainland Ecuador and show that the species has expanded its range significantly. Contrary to published records, A. b. rubrirostris has been present in mainland Ecuador at least since the early 20th century, although probably in low numbers. During the 20th century, the species increased its range along the entire coastlands of Ecuador and has reached the coasts of Colombia. The species has also extended its presence along the Andes, and we report the first breeding records of A. b. rubrirostris in the Andes at altitudes between 2360–2440 m, the highest across the entire range of the species. Additionally, we describe the transitioning plumage between ducklings and juveniles, which has not been portrayed in detail before.","PeriodicalId":54408,"journal":{"name":"Waterbirds","volume":"40 1","pages":"218 - 244"},"PeriodicalIF":0.3,"publicationDate":"2023-02-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"77513955","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Anastasia M. Maliguine, Christopher J. Latty, Elyssa M. Watford, T. Hollmen
Abstract. Determining embryo age is important for predicting hatch dates, planning nest visitation schedules, and as a model covariate examining factors affecting nest survival and behavior. Two common methods of estimating embryo age are egg candling and egg flotation (floating). Despite the reliance on these methods, there is little information regarding the repeatability of these techniques between multiple observers, or whether these techniques produce equivalent estimates. To determine how these methods compare and if precision of each method is biased by individual observers, paired observers candled and floated the same Common Eider (Somateria mollissima) eggs. We compared differences in embryo-age estimates across incubation between (1) candling and floating, (2) paired observers candling eggs, and (3) paired observers floating eggs. Floating and candling produced different embryo-age estimates during some periods of incubation. Although most estimates deviated by a few days, inconsistencies could impact results and statistical power when methods are interchanged between projects or across years. Observers derived different embryo-age estimates for candling, but not for floating, suggesting flotation may be more reliable. Our results suggest caution when combining candling and floating-derived data when collected across incubation stages. Investigators should consider how data collected by multiple observers may affect their research question.
{"title":"Comparability and Repeatability of Candling and Floating Methods for Estimating Embryo Age of Waterbird Eggs","authors":"Anastasia M. Maliguine, Christopher J. Latty, Elyssa M. Watford, T. Hollmen","doi":"10.1675/063.045.0208","DOIUrl":"https://doi.org/10.1675/063.045.0208","url":null,"abstract":"Abstract. Determining embryo age is important for predicting hatch dates, planning nest visitation schedules, and as a model covariate examining factors affecting nest survival and behavior. Two common methods of estimating embryo age are egg candling and egg flotation (floating). Despite the reliance on these methods, there is little information regarding the repeatability of these techniques between multiple observers, or whether these techniques produce equivalent estimates. To determine how these methods compare and if precision of each method is biased by individual observers, paired observers candled and floated the same Common Eider (Somateria mollissima) eggs. We compared differences in embryo-age estimates across incubation between (1) candling and floating, (2) paired observers candling eggs, and (3) paired observers floating eggs. Floating and candling produced different embryo-age estimates during some periods of incubation. Although most estimates deviated by a few days, inconsistencies could impact results and statistical power when methods are interchanged between projects or across years. Observers derived different embryo-age estimates for candling, but not for floating, suggesting flotation may be more reliable. Our results suggest caution when combining candling and floating-derived data when collected across incubation stages. Investigators should consider how data collected by multiple observers may affect their research question.","PeriodicalId":54408,"journal":{"name":"Waterbirds","volume":"14 1","pages":"183 - 188"},"PeriodicalIF":0.3,"publicationDate":"2023-02-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"81634259","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
D. Menning, B. Uher-Koch, Melanie J. Flamme, T. Simmons, J. Schmutz, S. Talbot
Abstract. Environmental DNA is a burgeoning tool used to address wide-ranging scientific questions, including determining diets of difficult-to-sample predators. Loons are large piscivorous diving birds that capture and consume prey underwater, making it nearly impossible to visually determine their diet via observation alone. Identifying species' diets is important for understanding basic life history traits, and revealing key prey species can clarify species' roles in complex trophic webs, aid in understanding population and community dynamics, and help identify critical habitat for protection. Current information about loon diet is largely anecdotal, and traditional non-observational methods for quantifying loon diet have limitations. Analysis of eDNA from loon feces may provide biologists with a non-invasive technique for determining diet without negative sampling effects, and with increased resolution as compared to other techniques. We surveyed lakes in two areas of northern Alaska for Yellow-billed Loons (Gavia adamsii). Loon fecal samples were collected opportunistically from latrine sites without disturbing any animals and analyzed using novel marker sets to determine loon species and diet. Fish species were detected in all fecal samples, the most common being Alaska blackfish (Dallia pectoralis), and ninespine stickleback (Pungitius pungitius). This research demonstrates that eDNA metabarcoding analyses of loon fecal samples can determine the specific loon species that deposited the feces and characterize the piscine portion of their diet with limited disturbance to the animals.
{"title":"eDNA Metabarcoding Analyses of Diet in Yellow-Billed Loons of Northern Alaska","authors":"D. Menning, B. Uher-Koch, Melanie J. Flamme, T. Simmons, J. Schmutz, S. Talbot","doi":"10.1675/063.045.0206","DOIUrl":"https://doi.org/10.1675/063.045.0206","url":null,"abstract":"Abstract. Environmental DNA is a burgeoning tool used to address wide-ranging scientific questions, including determining diets of difficult-to-sample predators. Loons are large piscivorous diving birds that capture and consume prey underwater, making it nearly impossible to visually determine their diet via observation alone. Identifying species' diets is important for understanding basic life history traits, and revealing key prey species can clarify species' roles in complex trophic webs, aid in understanding population and community dynamics, and help identify critical habitat for protection. Current information about loon diet is largely anecdotal, and traditional non-observational methods for quantifying loon diet have limitations. Analysis of eDNA from loon feces may provide biologists with a non-invasive technique for determining diet without negative sampling effects, and with increased resolution as compared to other techniques. We surveyed lakes in two areas of northern Alaska for Yellow-billed Loons (Gavia adamsii). Loon fecal samples were collected opportunistically from latrine sites without disturbing any animals and analyzed using novel marker sets to determine loon species and diet. Fish species were detected in all fecal samples, the most common being Alaska blackfish (Dallia pectoralis), and ninespine stickleback (Pungitius pungitius). This research demonstrates that eDNA metabarcoding analyses of loon fecal samples can determine the specific loon species that deposited the feces and characterize the piscine portion of their diet with limited disturbance to the animals.","PeriodicalId":54408,"journal":{"name":"Waterbirds","volume":"102 1","pages":"159 - 166"},"PeriodicalIF":0.3,"publicationDate":"2023-02-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"79515995","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
J. Belo, M. Dias, João Jara, Amélia Almeida, Frederico Morais, Carlos Silva, Joaquim Valadeiro, J. A. Alves
Abstract. Migratory wader populations are declining across all major flyways, mostly due to habitat loss and human disturbance. Portuguese wetlands act as key wintering and stop-over sites for many waders due to their strategic location in the East Atlantic Flyway. Despite their importance, there are major knowledge gaps in some areas, such as the Sado Estuary. The main goal of this study was to identify the phenological patterns and wintering trends of the most abundant wader species in this wetland, and to compare the results with the population trends found at regional and flyway scales. A comprehensive dataset of count data collected monthly in high-tide roosts under a set monitoring programme (2010–2019) was used. The results revealed strong declines in the overall number of waders and of three of the most abundant species—Avocet (Recurvisostra avosetta), Dunlin (Calidris alpina), and Common Ringed Plover (Charadrius hiaticula)—associated with a 21% reduction of the suitable high-tide roosts across the study area. These trends are similar to those compiled from winter counts for the entire Sado Estuary, and at regional (Tagus Estuary) and flyway levels. Our results highlight the need to maintain suitable high-tide roosts to contribute towards reverting current declines in wader populations.
{"title":"Synchronous Declines of Wintering Waders and High-Tide Roost Area in a Temperate Estuary: Results of a 10-Year Monitoring Programme","authors":"J. Belo, M. Dias, João Jara, Amélia Almeida, Frederico Morais, Carlos Silva, Joaquim Valadeiro, J. A. Alves","doi":"10.1675/063.045.0204","DOIUrl":"https://doi.org/10.1675/063.045.0204","url":null,"abstract":"Abstract. Migratory wader populations are declining across all major flyways, mostly due to habitat loss and human disturbance. Portuguese wetlands act as key wintering and stop-over sites for many waders due to their strategic location in the East Atlantic Flyway. Despite their importance, there are major knowledge gaps in some areas, such as the Sado Estuary. The main goal of this study was to identify the phenological patterns and wintering trends of the most abundant wader species in this wetland, and to compare the results with the population trends found at regional and flyway scales. A comprehensive dataset of count data collected monthly in high-tide roosts under a set monitoring programme (2010–2019) was used. The results revealed strong declines in the overall number of waders and of three of the most abundant species—Avocet (Recurvisostra avosetta), Dunlin (Calidris alpina), and Common Ringed Plover (Charadrius hiaticula)—associated with a 21% reduction of the suitable high-tide roosts across the study area. These trends are similar to those compiled from winter counts for the entire Sado Estuary, and at regional (Tagus Estuary) and flyway levels. Our results highlight the need to maintain suitable high-tide roosts to contribute towards reverting current declines in wader populations.","PeriodicalId":54408,"journal":{"name":"Waterbirds","volume":"47 1","pages":"141 - 149"},"PeriodicalIF":0.3,"publicationDate":"2023-02-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"85217430","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Abstract. Aggression between adult Common Loons (Gavia immer) occurs frequently during the breeding season. In the past, it was suspected that most instances of intraspecific aggression took place between adult males. However, recent reports from the field suggest that female adult loons also participate in these battles. Postmortem investigation has shown that the damage incurred during these battles can range from incidental to fatal injuries. Sternal punctures are the most lasting evidence of this trauma and can serve as long-term records. Nearly half (46%, n = 268/574) of the loons received at Tufts Wildlife Clinic for postmortem from 2007 to 2015 were found to have sternal punctures. We conducted a focused analysis of the sternal punctures of 102 of these adult loons (49 female and 53 male) and found no significant difference in the number, distribution, or severity of sternal punctures between male and female loons. This suggests that the frequency and intensity of aggressive physical contests are remarkably similar between sexes and that there is no gender difference in the severity of these battles. Female Common Loons participate in lethal combats as often as their male counterparts. These findings provide an opportunity to better understand and study the biological or behavioral drivers of this aggression that is prevalent among both male and female Common Loons.
{"title":"Sternal Punctures in Common Loons (Gavia immer): Gender and Territorial Aggression","authors":"A. Higgins, M. Hartwick, M. Pokras","doi":"10.1675/063.045.0109","DOIUrl":"https://doi.org/10.1675/063.045.0109","url":null,"abstract":"Abstract. Aggression between adult Common Loons (Gavia immer) occurs frequently during the breeding season. In the past, it was suspected that most instances of intraspecific aggression took place between adult males. However, recent reports from the field suggest that female adult loons also participate in these battles. Postmortem investigation has shown that the damage incurred during these battles can range from incidental to fatal injuries. Sternal punctures are the most lasting evidence of this trauma and can serve as long-term records. Nearly half (46%, n = 268/574) of the loons received at Tufts Wildlife Clinic for postmortem from 2007 to 2015 were found to have sternal punctures. We conducted a focused analysis of the sternal punctures of 102 of these adult loons (49 female and 53 male) and found no significant difference in the number, distribution, or severity of sternal punctures between male and female loons. This suggests that the frequency and intensity of aggressive physical contests are remarkably similar between sexes and that there is no gender difference in the severity of these battles. Female Common Loons participate in lethal combats as often as their male counterparts. These findings provide an opportunity to better understand and study the biological or behavioral drivers of this aggression that is prevalent among both male and female Common Loons.","PeriodicalId":54408,"journal":{"name":"Waterbirds","volume":"25 1","pages":"75 - 81"},"PeriodicalIF":0.3,"publicationDate":"2022-11-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"84012390","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Abstract. Roseate Terns (Sterna dougallii) frequently lay single eggs and desert them without incubating them. In a multi-year study, single deserted eggs comprised 4.2% of all clutches and 2.7% of all eggs. Laying dates and masses of single deserted eggs resembled those of first-laid eggs of female-male pairs and multi-female associations, but their masses differed from those of second-laid eggs of female-male pairs. An egg-transfer experiment showed that most single deserted eggs were fertile and that chicks hatched from them were viable when raised by female-male pairs. I hypothesize that single deserted eggs result from females laying their first eggs before the pair has settled on the location of a nest site. Fostering of single deserted eggs could be used to increase chick production in small colonies.
{"title":"Roseate Terns (Sterna dougallii) Frequently Desert Viable Eggs without Incubating Them","authors":"I. Nisbet","doi":"10.1675/063.045.0114","DOIUrl":"https://doi.org/10.1675/063.045.0114","url":null,"abstract":"Abstract. Roseate Terns (Sterna dougallii) frequently lay single eggs and desert them without incubating them. In a multi-year study, single deserted eggs comprised 4.2% of all clutches and 2.7% of all eggs. Laying dates and masses of single deserted eggs resembled those of first-laid eggs of female-male pairs and multi-female associations, but their masses differed from those of second-laid eggs of female-male pairs. An egg-transfer experiment showed that most single deserted eggs were fertile and that chicks hatched from them were viable when raised by female-male pairs. I hypothesize that single deserted eggs result from females laying their first eggs before the pair has settled on the location of a nest site. Fostering of single deserted eggs could be used to increase chick production in small colonies.","PeriodicalId":54408,"journal":{"name":"Waterbirds","volume":"7 1","pages":"113 - 116"},"PeriodicalIF":0.3,"publicationDate":"2022-11-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"81766729","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Mark A. Baran, Stephen Kress, Paula Shannon, D. Lyons, H. Major, A. Diamond
Abstract. To identify potential threats and prioritize areas for protection, modern conservation efforts rely on spatial data. While it is often impossible to study the movements of entire populations, we can examine patterns among individuals and groups to better understand populations as a whole. We used geolocator tags to determine where Atlantic Puffins (Fratercula arctica) at the southern edge of their range, vulnerable to warming waters and anthropogenic influence, spend the nonbreeding season, and whether birds from different colonies or parts of the same colony used different overwintering strategies. Between 2013 and 2017, tags were deployed on 97 puffins breeding on three islands in the Gulf of Maine: Machias Seal Island, Matinicus Rock, and Seal Island National Wildlife Refuge. Most tagged puffins remained in or near the Gulf of Maine throughout the autumn and early winter months, venturing as far south as Cape Hatteras (ca. 35°N) in February, March, and April, before returning to their respective colonies. Three individuals travelled north to the Gulf of St. Lawrence and waters around Newfoundland immediately after breeding, returning to the Gulf of Maine in mid-winter. We found no evidence of inter- or intra-colony differences in overwinter movement. This is the first study focusing on overwinter movements of puffins breeding at the southern edge of their range in North America and can assist in the development of policy regarding management and protection of important marine areas for puffins and other species.
{"title":"Overwinter Movement of Atlantic Puffins (Fratercula arctica) Breeding in the Gulf of Maine: Inter- and Intra-Colony Effects","authors":"Mark A. Baran, Stephen Kress, Paula Shannon, D. Lyons, H. Major, A. Diamond","doi":"10.1675/063.045.0103","DOIUrl":"https://doi.org/10.1675/063.045.0103","url":null,"abstract":"Abstract. To identify potential threats and prioritize areas for protection, modern conservation efforts rely on spatial data. While it is often impossible to study the movements of entire populations, we can examine patterns among individuals and groups to better understand populations as a whole. We used geolocator tags to determine where Atlantic Puffins (Fratercula arctica) at the southern edge of their range, vulnerable to warming waters and anthropogenic influence, spend the nonbreeding season, and whether birds from different colonies or parts of the same colony used different overwintering strategies. Between 2013 and 2017, tags were deployed on 97 puffins breeding on three islands in the Gulf of Maine: Machias Seal Island, Matinicus Rock, and Seal Island National Wildlife Refuge. Most tagged puffins remained in or near the Gulf of Maine throughout the autumn and early winter months, venturing as far south as Cape Hatteras (ca. 35°N) in February, March, and April, before returning to their respective colonies. Three individuals travelled north to the Gulf of St. Lawrence and waters around Newfoundland immediately after breeding, returning to the Gulf of Maine in mid-winter. We found no evidence of inter- or intra-colony differences in overwinter movement. This is the first study focusing on overwinter movements of puffins breeding at the southern edge of their range in North America and can assist in the development of policy regarding management and protection of important marine areas for puffins and other species.","PeriodicalId":54408,"journal":{"name":"Waterbirds","volume":"26 1","pages":"1 - 16"},"PeriodicalIF":0.3,"publicationDate":"2022-11-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"73100876","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Editorial: Transitioning Editorial Boards Through a Global Pandemic","authors":"K. G. Sundar","doi":"10.1675/063.045.0101","DOIUrl":"https://doi.org/10.1675/063.045.0101","url":null,"abstract":"","PeriodicalId":54408,"journal":{"name":"Waterbirds","volume":"62 1","pages":"i - iii"},"PeriodicalIF":0.3,"publicationDate":"2022-11-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"80494229","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
H. Madden, M. Leopold, F. Rivera-Milán, K. Verdel, Eline Eggermont, P. Jodice
Abstract. The daily nest-survival rates of Red-billed Tropicbirds (Phaethon aethereus) were estimated over six breeding seasons on St. Eustatius in the Caribbean. We analyzed 338 nesting attempts between 2013 and 2020. The daily survival rate (DSR) of tropicbird nests was modeled as a function of nest initiation date, sea surface temperature (SST), elevation, vegetation in front of the nest, and year. Yearly nest survival rates (± SE) of the best fitting models ranged from 0.21 ± 0.06–0.74 ± 0.13 (n = 338 nests). DSR of the most parsimonious models averaged 0.39 ± 0.04 during the incubation period, 0.83 ± 0.05 during the chick-rearing period, and 0.30 ± 0.04 during the nesting period (incubation through fledging) when data were pooled across all years. Models with linear and quadratic trends of nest initiation date combined with SST and elevation received strong support in the incubation and nesting periods. Nests initiated in peak nesting season, when SSTs were lower, had higher DSR estimates than nests initiated early or late in the season. Compared to studies of the same species from Saba and the Gulf of California, survival probability on St. Eustatius was lower during the incubation stage but higher during the chick-rearing period. Similar to populations in the Gulf of California, tropicbird reproduction differed and laying date varied among years, and survival was influenced by SST. Our results are consistent with a study on White-tailed Tropicbirds (Phaethon lepturus) in Bermuda which found that survival was affected by temporal factors rather than physical site characteristics. Our study contributes to a better understanding of the factors that influence Red-billed Tropicbird survival on a small Caribbean island.
{"title":"Reproductive Success of Red-Billed Tropicbirds (Phaethon aethereus) on St. Eustatius, Caribbean Netherlands","authors":"H. Madden, M. Leopold, F. Rivera-Milán, K. Verdel, Eline Eggermont, P. Jodice","doi":"10.1675/063.045.0106","DOIUrl":"https://doi.org/10.1675/063.045.0106","url":null,"abstract":"Abstract. The daily nest-survival rates of Red-billed Tropicbirds (Phaethon aethereus) were estimated over six breeding seasons on St. Eustatius in the Caribbean. We analyzed 338 nesting attempts between 2013 and 2020. The daily survival rate (DSR) of tropicbird nests was modeled as a function of nest initiation date, sea surface temperature (SST), elevation, vegetation in front of the nest, and year. Yearly nest survival rates (± SE) of the best fitting models ranged from 0.21 ± 0.06–0.74 ± 0.13 (n = 338 nests). DSR of the most parsimonious models averaged 0.39 ± 0.04 during the incubation period, 0.83 ± 0.05 during the chick-rearing period, and 0.30 ± 0.04 during the nesting period (incubation through fledging) when data were pooled across all years. Models with linear and quadratic trends of nest initiation date combined with SST and elevation received strong support in the incubation and nesting periods. Nests initiated in peak nesting season, when SSTs were lower, had higher DSR estimates than nests initiated early or late in the season. Compared to studies of the same species from Saba and the Gulf of California, survival probability on St. Eustatius was lower during the incubation stage but higher during the chick-rearing period. Similar to populations in the Gulf of California, tropicbird reproduction differed and laying date varied among years, and survival was influenced by SST. Our results are consistent with a study on White-tailed Tropicbirds (Phaethon lepturus) in Bermuda which found that survival was affected by temporal factors rather than physical site characteristics. Our study contributes to a better understanding of the factors that influence Red-billed Tropicbird survival on a small Caribbean island.","PeriodicalId":54408,"journal":{"name":"Waterbirds","volume":"30 1","pages":"39 - 50"},"PeriodicalIF":0.3,"publicationDate":"2022-11-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"84682697","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
D. V. Weseloh, I. Mazzocchi, David J. Moore, C. Pekarik, Donald J. Tyerman, L. Shutt, C. Hebert, D. Crump, G. Fox, L. Harper, Karen Macdonald, Andrea Chreston, J. S. Quinn
Abstract. Colonies of Herring (Larus argentatus) and/or Ring-billed Gulls (L. delawarensis) on Lake Ontario and the upper St. Lawrence River were searched annually, 1981–2018, for nesting Great Black-backed Gulls (L. marinus). Great Black-backed Gulls nested at nine sites where both Herring and Ring-billed Gulls nested, at seven sites with only Herring Gulls, and at one site where they nested solitarily. Nests per site ranged from 1–21 on Lake Ontario and 1–5 on the St. Lawrence River. On Lake Ontario, nest numbers increased from six nests in 1981 to 51 nests in 2001 (+ 11.3%/yr), then declined to zero nests in 2008, where they have remained ever since. The decline in nesting Great Black-backed Gulls was due primarily to mortality from Type E botulism that affected that species to a greater degree than other gull species, probably because of their superior ability to dominate and scavenge toxin-laden carrion. Temporal changes in routes and efficiency of botulinum toxin transfer likely explain why Great Black-back Gulls were initially able to colonize Lake Ontario, but have undergone extirpation in recent times. Our results illustrate how changes in disease prevalence in the Great Lakes can degrade environmental quality to the extent that some species simply cannot persist.
{"title":"Colonization and Extirpation of Great Black-Backed Gulls (Larus marinus) Nesting on Lake Ontario and the Upper St. Lawrence River","authors":"D. V. Weseloh, I. Mazzocchi, David J. Moore, C. Pekarik, Donald J. Tyerman, L. Shutt, C. Hebert, D. Crump, G. Fox, L. Harper, Karen Macdonald, Andrea Chreston, J. S. Quinn","doi":"10.1675/063.045.0108","DOIUrl":"https://doi.org/10.1675/063.045.0108","url":null,"abstract":"Abstract. Colonies of Herring (Larus argentatus) and/or Ring-billed Gulls (L. delawarensis) on Lake Ontario and the upper St. Lawrence River were searched annually, 1981–2018, for nesting Great Black-backed Gulls (L. marinus). Great Black-backed Gulls nested at nine sites where both Herring and Ring-billed Gulls nested, at seven sites with only Herring Gulls, and at one site where they nested solitarily. Nests per site ranged from 1–21 on Lake Ontario and 1–5 on the St. Lawrence River. On Lake Ontario, nest numbers increased from six nests in 1981 to 51 nests in 2001 (+ 11.3%/yr), then declined to zero nests in 2008, where they have remained ever since. The decline in nesting Great Black-backed Gulls was due primarily to mortality from Type E botulism that affected that species to a greater degree than other gull species, probably because of their superior ability to dominate and scavenge toxin-laden carrion. Temporal changes in routes and efficiency of botulinum toxin transfer likely explain why Great Black-back Gulls were initially able to colonize Lake Ontario, but have undergone extirpation in recent times. Our results illustrate how changes in disease prevalence in the Great Lakes can degrade environmental quality to the extent that some species simply cannot persist.","PeriodicalId":54408,"journal":{"name":"Waterbirds","volume":"31 1","pages":"62 - 74"},"PeriodicalIF":0.3,"publicationDate":"2022-11-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"76667118","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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