Differentiation of subspecies and sexes of Beringian Dunlins using morphometric measures |
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| Authors: | H River Gates Stephen Yezerinac Abby N Powell Pavel S Tomkovich Olga P Valchuk Richard B Lanctot |
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| Institution: | 1. U.S. Fish and Wildlife Service, Migratory Bird Management, , Anchorage, Alaska 99503, USA;2. Department of Biology and Wildlife, University of Alaska Fairbanks, , Fairbanks, Alaska, 99775 USA;3. ABR Inc.—Environmental Research & Services, , Anchorage, Alaska 99524 USA;4. Biology Department, Mount Allison University, , Sackville, New Brunswick, E4L 1G7, Canada;5. U.S. Geological Survey, Alaska Cooperative Fish and Wildlife Research Unit, University of Alaska Fairbanks, , Fairbanks, Alaska, 99775‐7020 USA;6. Zoological Museum, Moscow State University, , Moscow, 125009 Russia;7. Institute of Biology and Soil Science, Russian Academy of Sciences, , Vladivostok, Russia |
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| Abstract: | Five subspecies of Dunlins (Calidris alpina) that breed in Beringia are potentially sympatric during the non‐breeding season. Studying their ecology during this period requires techniques to distinguish individuals by subspecies. Our objectives were to determine (1) if five morphometric measures (body mass, culmen, head, tarsus, and wing chord) differed between sexes and among subspecies (C. a. actites, arcticola, kistchinski, pacifica, and sakhalina), and (2) if these differences were sufficient to allow for correct classification of individuals using equations derived from discriminant function analyses. We conducted analyses using morphometric data from 10 Dunlin populations breeding in northern Russia and Alaska, USA. Univariate tests revealed significant differences between sexes in most morphometric traits of all subspecies, and discriminant function equations predicted the sex of individuals with an accuracy of 83–100% for each subspecies. We provide equations to determine sex and subspecies of individuals in mixed subspecies groups, including the (1) Western Alaska group of arcticola and pacifica (known to stage together in western Alaska) and (2) East Asia group of arcticola, actites, kistchinski, and sakhalina (known to winter together in East Asia). Equations that predict the sex of individuals in mixed groups had classification accuracies between 75% and 87%, yielding reliable classification equations. We also provide equations that predict the subspecies of individuals with an accuracy of 22–96% for different mixed subspecies groups. When the sex of individuals can be predetermined, the accuracy of these equations is increased substantially. Investigators are cautioned to consider limitations due to age and feather wear when using these equations during the non‐breeding season. These equations will allow determination of sexual and subspecies segregation in non‐breeding areas, allowing implementation of taxonomic‐specific conservation actions. |
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| Keywords: | Calidris alpina discriminant function analysis migratory connectivity shorebird wader |
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