A. Millones, A. Morgenthaler, P. Gandini, E. Frere
Abstract. The overall population size and trend of the Magellanic Penguin (Spheniscus magellanicus) is uncertain and population estimates are available only for few locations. The last complete census along its central-southern distribution range in Argentina, province of Santa Cruz, was made in the 1990s. This study updates the breeding population size along Santa Cruz. Population estimates were compared with the last complete census, and trends were studied when it was possible. With 353,256 estimated breeding pairs, the overall population in Santa Cruz remained relatively stable after 25 years. The Santa Cruz population represents 31% of the Argentine Patagonian coast population and could represent between 22 and 30% of the species' global population. Colony sizes varied between 9 and 127,492 breeding pairs. Changes in abundance differed among locations, with individual colonies showing increasing, decreasing, or stable trends, which suggests that local factors determine population dynamics. The most significant increases (> 40%) were observed in the southern sector of Santa Cruz. Contrary to what was observed at the north of the distribution range in the province of Chubut, where trends of several colonies were inversely related to colony size, in Santa Cruz most of the largest colonies remained stable or even increased from the 1990s onwards.
{"title":"Population Numbers of the Magellanic Penguin along Its Central-Southern Distribution in Argentina: An Update after 25 Years","authors":"A. Millones, A. Morgenthaler, P. Gandini, E. Frere","doi":"10.1675/063.044.0411","DOIUrl":"https://doi.org/10.1675/063.044.0411","url":null,"abstract":"Abstract. The overall population size and trend of the Magellanic Penguin (Spheniscus magellanicus) is uncertain and population estimates are available only for few locations. The last complete census along its central-southern distribution range in Argentina, province of Santa Cruz, was made in the 1990s. This study updates the breeding population size along Santa Cruz. Population estimates were compared with the last complete census, and trends were studied when it was possible. With 353,256 estimated breeding pairs, the overall population in Santa Cruz remained relatively stable after 25 years. The Santa Cruz population represents 31% of the Argentine Patagonian coast population and could represent between 22 and 30% of the species' global population. Colony sizes varied between 9 and 127,492 breeding pairs. Changes in abundance differed among locations, with individual colonies showing increasing, decreasing, or stable trends, which suggests that local factors determine population dynamics. The most significant increases (> 40%) were observed in the southern sector of Santa Cruz. Contrary to what was observed at the north of the distribution range in the province of Chubut, where trends of several colonies were inversely related to colony size, in Santa Cruz most of the largest colonies remained stable or even increased from the 1990s onwards.","PeriodicalId":54408,"journal":{"name":"Waterbirds","volume":"24 1","pages":"499 - 508"},"PeriodicalIF":0.3,"publicationDate":"2022-07-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"85678838","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. The critically endangered White-bellied Heron (Ardea insignis) is a piscivorous visual forager that prefers to forage in fast-flowing freshwater rivers. This study highlights White-bellied Heron foraging behavior in the fast-flowing rivers of Namdapha Tiger Reserve during 2013–2017. The herons spent significantly more time and also made more foraging attempts while foraging in shallow water (foraging time: 61.45 ± 15.55%; strike rate: 1.70 strikes/hr). Herons were more successful in catching fishes when they foraged facing upstream (capture rate: 0.62 fishes caught/hr) with increased capture efficiency (44.62%). White-bellied Herons caught the majority (60.98%) of small sized fishes (≤ 9 cm) while facing upstream and the majority (60.92%) of large sized fishes (> 18 cm) while facing downstream. These findings shed light on the manner in which this rare and critically endangered bird is adapted to life on fast-flowing rivers and the importance of these unique places for its conservation.
{"title":"Foraging Ecology of White-Bellied Heron (Ardea insignis) in the Fast-Flowing Rivers of Namdapha Tiger Reserve, Arunachal Pradesh, India","authors":"H. S. Mondal, G. Maheswaran","doi":"10.1675/063.044.0401","DOIUrl":"https://doi.org/10.1675/063.044.0401","url":null,"abstract":"Abstract. The critically endangered White-bellied Heron (Ardea insignis) is a piscivorous visual forager that prefers to forage in fast-flowing freshwater rivers. This study highlights White-bellied Heron foraging behavior in the fast-flowing rivers of Namdapha Tiger Reserve during 2013–2017. The herons spent significantly more time and also made more foraging attempts while foraging in shallow water (foraging time: 61.45 ± 15.55%; strike rate: 1.70 strikes/hr). Herons were more successful in catching fishes when they foraged facing upstream (capture rate: 0.62 fishes caught/hr) with increased capture efficiency (44.62%). White-bellied Herons caught the majority (60.98%) of small sized fishes (≤ 9 cm) while facing upstream and the majority (60.92%) of large sized fishes (> 18 cm) while facing downstream. These findings shed light on the manner in which this rare and critically endangered bird is adapted to life on fast-flowing rivers and the importance of these unique places for its conservation.","PeriodicalId":54408,"journal":{"name":"Waterbirds","volume":"103 1","pages":"389 - 396"},"PeriodicalIF":0.3,"publicationDate":"2022-07-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"85850932","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. The nest site characteristics of two endangered seabird species–the Hawaiian Petrel Pterodroma sandwichensis and Newell's Shearwater Puffinus newelli–on Kaua‘i were considered. Burrows of both species were predominantly found under tree roots or small caves on steep slopes and were associated with native plants, both in the canopy (particularly Metrosideros polymorpha) and the understory (particularly Dicranopteris linearis). There were, however, marked differences between the two species. Hawaiian Petrels were found at higher elevations with a shorter, patchy canopy and more open understory. Models using microhabitat variables were better able to classify burrows than those using landscape topographic metrics, suggesting that metrics describing the immediate area around the burrow are more important to burrow selection. A comparative model indicated that elevation and maximum vegetation height were the strongest variables in classifying between the two species. Understanding microhabitat needs for these species is important for locating new colonies and for the successful implementation of management actions such as colony creation through social attraction. Furthermore, with the spread of Rapid’Ōhi’a Death canker disease Ceratocystis huliohia on Kaua‘i, the heavy reliance by both species on forest dominated by M. polymorpha (the tree killed by this disease) should be of increasing consideration for conservation efforts targeting these species.
{"title":"Nest Site Characteristics of Two Endangered Seabirds in Montane Wet Forests on the Island of Kaua‘i, Hawai‘i, USA","authors":"A. Raine, S. Driskill, J. Rothe, Megan Vynne","doi":"10.1675/063.044.0408","DOIUrl":"https://doi.org/10.1675/063.044.0408","url":null,"abstract":"Abstract. The nest site characteristics of two endangered seabird species–the Hawaiian Petrel Pterodroma sandwichensis and Newell's Shearwater Puffinus newelli–on Kaua‘i were considered. Burrows of both species were predominantly found under tree roots or small caves on steep slopes and were associated with native plants, both in the canopy (particularly Metrosideros polymorpha) and the understory (particularly Dicranopteris linearis). There were, however, marked differences between the two species. Hawaiian Petrels were found at higher elevations with a shorter, patchy canopy and more open understory. Models using microhabitat variables were better able to classify burrows than those using landscape topographic metrics, suggesting that metrics describing the immediate area around the burrow are more important to burrow selection. A comparative model indicated that elevation and maximum vegetation height were the strongest variables in classifying between the two species. Understanding microhabitat needs for these species is important for locating new colonies and for the successful implementation of management actions such as colony creation through social attraction. Furthermore, with the spread of Rapid’Ōhi’a Death canker disease Ceratocystis huliohia on Kaua‘i, the heavy reliance by both species on forest dominated by M. polymorpha (the tree killed by this disease) should be of increasing consideration for conservation efforts targeting these species.","PeriodicalId":54408,"journal":{"name":"Waterbirds","volume":"13 1","pages":"472 - 482"},"PeriodicalIF":0.3,"publicationDate":"2022-07-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"90039121","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}
W. Bean, Sharon Dulava, Mark Bauer, Jeff L. Sloan, Orien M Richmond
Abstract. The number of breeding pairs is an essential indicator for assessing waterbird colony status. Accurate estimates require distinguishing stationary adults (likely to be breeders on nests) from nonstationary adults (likely to be loafing or foraging breeders or non-breeders). High-resolution multi-temporal aerial imagery obtained from manned aircraft, satellites, or unmanned aircraft systems (UAS) can be analyzed to determine bird movements and derive estimates of the number of stationary adults, which corresponds to the number of active nests, and thereby breeding pairs. Automated detection of stationary objects, such as nesting waterbirds, can be complicated by small positional changes of objects, either because of image co-registration errors or because the object slightly shifts position. A non-parametric, point-based approach was developed to distinguish stationary birds from moving birds using sequences of either two or three consecutive remotely-sensed images. This approach was tested with simulated data and during a case study of nesting American White Pelicans (Pelecanus erythrorhynchos). In both cases, the non-parametric point-based approach had higher accuracy than other established methods such as ground counts. Using two consecutive images had higher sensitivity (correct classification of stationary birds) while using three consecutive images had higher specificity (correct classification of nonstationary birds). This novel, multi-temporal nearest-neighbor method is most useful when positional shifts of stationary animals is low between consecutive images.
{"title":"A Novel Automated Method for Point-Based Change Detection Increases Estimation Accuracy of Breeding Pairs in Waterbird Colonies","authors":"W. Bean, Sharon Dulava, Mark Bauer, Jeff L. Sloan, Orien M Richmond","doi":"10.1675/063.044.0302","DOIUrl":"https://doi.org/10.1675/063.044.0302","url":null,"abstract":"Abstract. The number of breeding pairs is an essential indicator for assessing waterbird colony status. Accurate estimates require distinguishing stationary adults (likely to be breeders on nests) from nonstationary adults (likely to be loafing or foraging breeders or non-breeders). High-resolution multi-temporal aerial imagery obtained from manned aircraft, satellites, or unmanned aircraft systems (UAS) can be analyzed to determine bird movements and derive estimates of the number of stationary adults, which corresponds to the number of active nests, and thereby breeding pairs. Automated detection of stationary objects, such as nesting waterbirds, can be complicated by small positional changes of objects, either because of image co-registration errors or because the object slightly shifts position. A non-parametric, point-based approach was developed to distinguish stationary birds from moving birds using sequences of either two or three consecutive remotely-sensed images. This approach was tested with simulated data and during a case study of nesting American White Pelicans (Pelecanus erythrorhynchos). In both cases, the non-parametric point-based approach had higher accuracy than other established methods such as ground counts. Using two consecutive images had higher sensitivity (correct classification of stationary birds) while using three consecutive images had higher specificity (correct classification of nonstationary birds). This novel, multi-temporal nearest-neighbor method is most useful when positional shifts of stationary animals is low between consecutive images.","PeriodicalId":54408,"journal":{"name":"Waterbirds","volume":"10 1","pages":"277 - 288"},"PeriodicalIF":0.3,"publicationDate":"2022-04-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"73289141","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. Little Tern (Sternula albifrons) prey composition was studied on a sandy islet in inland Andong Lake, Republic of Korea, during the breeding season (April to July 2018). Two remote-control video cameras with 4K-resolution were set on the islet to identify prey and determine whether prey species composition or size differed among breeding stages. On still images in which terns had prey in their bills (n = 1,275), prey species were identified, classified to five length-categories, and compared among breeding stages. Freshwater fishes dominated the observed diet (100%; 11 species overall), where the landlocked pond smelt (Hypomesus nipponensis; 80.8%) and largemouth bass (Micropterus salmoides; 13.7%) were main prey species. The mean prey length was 51.0 ± 20.89 mm, where 50.1–75.0 mm prey was the most frequent in the diet (42.2%) and varied significantly among breeding stages; 50.1–75.0 mm prey were most frequent during courtship and incubation stages, whereas 1.0–25.0 mm prey were most frequent at the chick-rearing stage. Surface water temperatures exceeded the upper thermal tolerance of the primary prey species at a date coincidental with tern departure from the colony.
{"title":"Identification of Little Tern (Sternula albifrons) Prey in Inland Andong Lake, Korea Using Video Image Analysis","authors":"Dong-Man Shin, Jeong-ho Han","doi":"10.1675/063.044.0301","DOIUrl":"https://doi.org/10.1675/063.044.0301","url":null,"abstract":"Abstract. Little Tern (Sternula albifrons) prey composition was studied on a sandy islet in inland Andong Lake, Republic of Korea, during the breeding season (April to July 2018). Two remote-control video cameras with 4K-resolution were set on the islet to identify prey and determine whether prey species composition or size differed among breeding stages. On still images in which terns had prey in their bills (n = 1,275), prey species were identified, classified to five length-categories, and compared among breeding stages. Freshwater fishes dominated the observed diet (100%; 11 species overall), where the landlocked pond smelt (Hypomesus nipponensis; 80.8%) and largemouth bass (Micropterus salmoides; 13.7%) were main prey species. The mean prey length was 51.0 ± 20.89 mm, where 50.1–75.0 mm prey was the most frequent in the diet (42.2%) and varied significantly among breeding stages; 50.1–75.0 mm prey were most frequent during courtship and incubation stages, whereas 1.0–25.0 mm prey were most frequent at the chick-rearing stage. Surface water temperatures exceeded the upper thermal tolerance of the primary prey species at a date coincidental with tern departure from the colony.","PeriodicalId":54408,"journal":{"name":"Waterbirds","volume":"2015 1","pages":"269 - 276"},"PeriodicalIF":0.3,"publicationDate":"2022-04-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"87095376","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}
M. M. Hernandez, M. P. Berón, F. Zumpano, G. Giardino, J. P. Seco Pon
Abstract. This work aims to provide information regarding the behavioral ecology of the least studied of the two sheathbill species, the Snowy Sheathbill (Chionis albus), wintering in northern Argentina in a male South American Sea Lion (Otaria flavescens) haul-out. Data about bird abundances and time allocated to behaviors was gathered during the final stage of three consecutive non-breeding seasons. Significant differences were found in the abundance between and within seasons. Overall, sheathbills allocated most of their time to foraging, followed by resting and self-maintaining, with the least of the time allocated to agonistic behaviors. The results obtained by the authors demonstrated that the Snowy Sheathbill recurrently used the local sea-lion haul-out as a foraging ground, with steady numbers throughout the non-breeding seasons.
{"title":"Time-Activity Budget of the Snowy Sheathbill (Chionis albus) Wintering at a Sea Lion (Otaria flavescens) Haul-Out in Argentina","authors":"M. M. Hernandez, M. P. Berón, F. Zumpano, G. Giardino, J. P. Seco Pon","doi":"10.1675/063.044.0313","DOIUrl":"https://doi.org/10.1675/063.044.0313","url":null,"abstract":"Abstract. This work aims to provide information regarding the behavioral ecology of the least studied of the two sheathbill species, the Snowy Sheathbill (Chionis albus), wintering in northern Argentina in a male South American Sea Lion (Otaria flavescens) haul-out. Data about bird abundances and time allocated to behaviors was gathered during the final stage of three consecutive non-breeding seasons. Significant differences were found in the abundance between and within seasons. Overall, sheathbills allocated most of their time to foraging, followed by resting and self-maintaining, with the least of the time allocated to agonistic behaviors. The results obtained by the authors demonstrated that the Snowy Sheathbill recurrently used the local sea-lion haul-out as a foraging ground, with steady numbers throughout the non-breeding seasons.","PeriodicalId":54408,"journal":{"name":"Waterbirds","volume":"152 1","pages":"376 - 381"},"PeriodicalIF":0.3,"publicationDate":"2022-04-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"85391888","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}
A. R. Carreiro, J. Bried, Zoe Deakin, K. B. Jones, R.J. Thomas, W. Symondson, J. Ramos, Renata Medeiros
Abstract. Although studying the diet of threatened species is crucial in terms of conservation, the diet of the Madeiran Storm Petrel (Hydrobates castro) and the vulnerable, Azores-endemic Monteiro's Storm Petrel (H. monteiroi) is mostly unknown. The only information available to date comes from anecdotal observations, analysis of mercury levels and stable isotopes. Here is presented the first insights into prey consumption by adults and chicks from the two species breeding in the Azores Archipelago, Portugal, in the mid-Atlantic Ocean. The rapidly developing field of metabarcoding was used to identify dietary items from fecal samples, to species level where possible. A total of thirteen fish, five cephalopod, one crustacean and two oligochaete operational taxonomic units (OTUs) were detected. Results suggest that both petrel species feed mainly on myctophid fish. However, differences were detected between the prey species consumed by (i) H. monteiroi and H. castro, (ii) two distinct H. castro populations (Vila and Praia islets), and (iii) chicks and adults within the same population.
摘要虽然研究濒危物种的饮食对保护至关重要，但马德拉风暴海燕(Hydrobates castro)和亚速尔特有的脆弱的蒙泰罗风暴海燕(H. monteiroi)的饮食大多是未知的。迄今为止可获得的唯一信息来自轶事观察、对汞水平和稳定同位素的分析。这是对在大西洋中部葡萄牙亚速尔群岛繁殖的两个物种的成年和雏鸟的猎物消耗的第一次见解。快速发展的元条形码领域被用于从粪便样本中识别饮食项目，在可能的情况下达到物种水平。共检出鱼类13种，头足类5种，甲壳类1种，寡毛类2种。结果表明，这两种海燕主要以嗜菌鱼为食。然而，发现了:(i) H. monteiroi和H. castro所消耗的猎物种类之间的差异，(ii)两个不同的H. castro种群(Vila和Praia岛)，以及(iii)同一种群内的雏鸟和成虫。
{"title":"First Insights into the Diet Composition of Madeiran and Monteiro's Storm Petrels (Hydrobates castro and H. monteiroi) Breeding in the Azores","authors":"A. R. Carreiro, J. Bried, Zoe Deakin, K. B. Jones, R.J. Thomas, W. Symondson, J. Ramos, Renata Medeiros","doi":"10.1675/063.044.0304","DOIUrl":"https://doi.org/10.1675/063.044.0304","url":null,"abstract":"Abstract. Although studying the diet of threatened species is crucial in terms of conservation, the diet of the Madeiran Storm Petrel (Hydrobates castro) and the vulnerable, Azores-endemic Monteiro's Storm Petrel (H. monteiroi) is mostly unknown. The only information available to date comes from anecdotal observations, analysis of mercury levels and stable isotopes. Here is presented the first insights into prey consumption by adults and chicks from the two species breeding in the Azores Archipelago, Portugal, in the mid-Atlantic Ocean. The rapidly developing field of metabarcoding was used to identify dietary items from fecal samples, to species level where possible. A total of thirteen fish, five cephalopod, one crustacean and two oligochaete operational taxonomic units (OTUs) were detected. Results suggest that both petrel species feed mainly on myctophid fish. However, differences were detected between the prey species consumed by (i) H. monteiroi and H. castro, (ii) two distinct H. castro populations (Vila and Praia islets), and (iii) chicks and adults within the same population.","PeriodicalId":54408,"journal":{"name":"Waterbirds","volume":"19 1","pages":"300 - 307"},"PeriodicalIF":0.3,"publicationDate":"2022-04-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"73344117","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}
E. Forys, Carly Naundorff, K. M. Kennedy, Paige T. Paddock
Abstract. This study investigated if morphological measurements made from digital photographs of banded adult Black Skimmers (Rynchops niger), using alphanumeric field readable leg bands as a scale reference, can be used to determine their sex. Black Skimmers are known for their extreme sexual dimorophism and make an excellent study subject. Measurements made in the field using calipers to determine length of the exposed culmen of skimmer chicks were significantly correlated to measurements made by three technicians using open-source software (ImageJ) measuring the culmen from photographs, with little variability among technicians. To determine sex, ImageJ was used to measure the culmen, bill depth at base, lower mandible and head + culmen lengths from photographs of 24 known sex adult skimmers (11 female, 13 male). Males were significantly larger than females for all four measurements and a stepwise Discriminant Function Analysis (DFA) using all 4 measurements retained exposed culmen and bill depth as the best predictor variables. This model correctly classified 100% of known sex males and females. Using the DFA equation, 40 additional banded skimmers were classified, and it was determined that 46 of the banded skimmers that were photographed as adults were male and 18 were female. Using a field readable band as a reference scale for other measurements may prove useful for research on other sexually dimorphic species that are banded and later photographed in the wild.
{"title":"Use of Morphometric Measurements of Photographs of a Sexually Dimorphic Bird to Determine Sex","authors":"E. Forys, Carly Naundorff, K. M. Kennedy, Paige T. Paddock","doi":"10.1675/063.044.0307","DOIUrl":"https://doi.org/10.1675/063.044.0307","url":null,"abstract":"Abstract. This study investigated if morphological measurements made from digital photographs of banded adult Black Skimmers (Rynchops niger), using alphanumeric field readable leg bands as a scale reference, can be used to determine their sex. Black Skimmers are known for their extreme sexual dimorophism and make an excellent study subject. Measurements made in the field using calipers to determine length of the exposed culmen of skimmer chicks were significantly correlated to measurements made by three technicians using open-source software (ImageJ) measuring the culmen from photographs, with little variability among technicians. To determine sex, ImageJ was used to measure the culmen, bill depth at base, lower mandible and head + culmen lengths from photographs of 24 known sex adult skimmers (11 female, 13 male). Males were significantly larger than females for all four measurements and a stepwise Discriminant Function Analysis (DFA) using all 4 measurements retained exposed culmen and bill depth as the best predictor variables. This model correctly classified 100% of known sex males and females. Using the DFA equation, 40 additional banded skimmers were classified, and it was determined that 46 of the banded skimmers that were photographed as adults were male and 18 were female. Using a field readable band as a reference scale for other measurements may prove useful for research on other sexually dimorphic species that are banded and later photographed in the wild.","PeriodicalId":54408,"journal":{"name":"Waterbirds","volume":"142 1","pages":"324 - 329"},"PeriodicalIF":0.3,"publicationDate":"2022-04-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"77346881","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}
B. MacCallum, Alice Paquet, Lisa J. Bate, C. Hammond, Kristina M. Smucker, Lucas J. Savoy, S. Patla, W. Boyd
Abstract. The Harlequin Duck (Histrionicus histrionicus) is a species of conservation priority in western North America. Harlequin Ducks breed in small, isolated populations and have specific nesting requirements. Archival, light-level geolocators are increasingly being used as a low-cost, non-invasive tracking technology to explore migratory connectivity. From 2015-2019, geolocators were deployed on 70 Harlequin Ducks in breeding streams of the Rocky Mountains, Canada and USA, to obtain information on connectivity (breeding to non-breeding), molt-winter sites, dispersal, and breeding phenology. Twenty-two of the 70 geolocators were retrieved from locations in the Rocky Mountains (Alberta, Canada; Montana and Wyoming, USA) and analyzed using the TwGeos and FLightR R packages. Harlequin Ducks from the warmer climate of northwest Montana migrated in spring and started incubation one to two weeks earlier than ducks in west-central Alberta and the greater Yellowstone area. During the non-breeding period, individuals dispersed along the Pacific coast, from Oregon to the Alaskan Panhandle, independent of breeding site. Females that incubated successfully spent 32-34 days incubating, which is several days longer than what is in the literature. Use of geolocators provided detailed information about migration connectivity and breeding behavior in a cost effective and relatively non-invasive manner.
{"title":"Migratory Connectivity and Nesting Behavior in Harlequin Ducks (Histrionicus histrionicus) Based on Light-Level Geolocator Data","authors":"B. MacCallum, Alice Paquet, Lisa J. Bate, C. Hammond, Kristina M. Smucker, Lucas J. Savoy, S. Patla, W. Boyd","doi":"10.1675/063.044.0308","DOIUrl":"https://doi.org/10.1675/063.044.0308","url":null,"abstract":"Abstract. The Harlequin Duck (Histrionicus histrionicus) is a species of conservation priority in western North America. Harlequin Ducks breed in small, isolated populations and have specific nesting requirements. Archival, light-level geolocators are increasingly being used as a low-cost, non-invasive tracking technology to explore migratory connectivity. From 2015-2019, geolocators were deployed on 70 Harlequin Ducks in breeding streams of the Rocky Mountains, Canada and USA, to obtain information on connectivity (breeding to non-breeding), molt-winter sites, dispersal, and breeding phenology. Twenty-two of the 70 geolocators were retrieved from locations in the Rocky Mountains (Alberta, Canada; Montana and Wyoming, USA) and analyzed using the TwGeos and FLightR R packages. Harlequin Ducks from the warmer climate of northwest Montana migrated in spring and started incubation one to two weeks earlier than ducks in west-central Alberta and the greater Yellowstone area. During the non-breeding period, individuals dispersed along the Pacific coast, from Oregon to the Alaskan Panhandle, independent of breeding site. Females that incubated successfully spent 32-34 days incubating, which is several days longer than what is in the literature. Use of geolocators provided detailed information about migration connectivity and breeding behavior in a cost effective and relatively non-invasive manner.","PeriodicalId":54408,"journal":{"name":"Waterbirds","volume":"1 1","pages":"330 - 342"},"PeriodicalIF":0.3,"publicationDate":"2022-04-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"83124732","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. Birds have been monitored as indicators of ecosystem health in both the freshwater and marine habitats of south Florida, USA for decades. This study reports on nine years (2010-2018) of monthly systematic surveys of breeding waterbird colonies in Biscayne National Park. Overall, 89% of active nests in the park belonged to Double-crested Cormorants (Phalacrocorax auritus). The annual sum of nest counts within the study area grew by 58% over the course of the study. This growth in the nesting population is driven by a 61% growth in northern colonies. During this same time period, the southern colonies declined to less than half their original size. These opposing trends coincide with differences in habitat quality (salinity, chlorophyll, sea grass density, and/or prey abundance) between the two regions. In addition, Hurricane Irma strongly impacted the nesting Double-crested Cormorants, suggesting a loss of nearly 400 nests, although four months post-storm nesting was back to normal levels. Finally, two colonies appear to have started during the study period in close proximity to recently completed Biscayne Bay Coastal Wetlands restoration projects. One of these colonies supported a maximum of over 350 nests.
{"title":"Spatial and Temporal Patterns of Double-Crested Cormorant (Phalacrocorax auritus) Breeding Over Nine Years in Biscayne National Park, Florida","authors":"Donna M. Marain, K. Whelan, Robert Muxo","doi":"10.1675/063.044.0303","DOIUrl":"https://doi.org/10.1675/063.044.0303","url":null,"abstract":"Abstract. Birds have been monitored as indicators of ecosystem health in both the freshwater and marine habitats of south Florida, USA for decades. This study reports on nine years (2010-2018) of monthly systematic surveys of breeding waterbird colonies in Biscayne National Park. Overall, 89% of active nests in the park belonged to Double-crested Cormorants (Phalacrocorax auritus). The annual sum of nest counts within the study area grew by 58% over the course of the study. This growth in the nesting population is driven by a 61% growth in northern colonies. During this same time period, the southern colonies declined to less than half their original size. These opposing trends coincide with differences in habitat quality (salinity, chlorophyll, sea grass density, and/or prey abundance) between the two regions. In addition, Hurricane Irma strongly impacted the nesting Double-crested Cormorants, suggesting a loss of nearly 400 nests, although four months post-storm nesting was back to normal levels. Finally, two colonies appear to have started during the study period in close proximity to recently completed Biscayne Bay Coastal Wetlands restoration projects. One of these colonies supported a maximum of over 350 nests.","PeriodicalId":54408,"journal":{"name":"Waterbirds","volume":"478 1","pages":"289 - 299"},"PeriodicalIF":0.3,"publicationDate":"2022-04-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"74709348","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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