Journal of Ornithology

, Volume 148, Issue 4, pp 435–442 | Cite as

Morphological and genetic sex identification of white-tailed eagle Haliaeetus albicilla nestlings

  • Björn HelanderEmail author
  • Frank Hailer
  • Carles Vilà
Original Article


Identifying the sex of bird nestlings is relevant to studies of behaviour and ecology and is often a central issue in the management of endangered or captive populations. The white-tailed eagle Haliaeetus albicilla is a formerly threatened Eurasian raptor which is closely monitored in many countries due to its high exposure to environmental pollutants in the food chain. The aim of this study was to evaluate the reliability of sex identification methods for white-tailed eagle nestlings based on morphological measurements that can be recorded at the nest by a single person and with minimum disturbance. The sex of each bird was independently determined using molecular (genetic) methods. One measure of tarsus width allowed the correct identification of sex for 96% of the nestlings from southern and central Sweden. However, we found that the criteria for sex identification were not directly applicable to the population in Swedish Lapland, where nestlings are typically thinner, probably due to a limited food supply. These results show that sexing in the field of white-tailed eagle nestlings can be feasible with high accuracy based on a limited number of measurements. However, the criteria employed to separate sexes may have to be adjusted for each population.


Haliaeetusalbicilla Molecular sexing Morphological sexing Sexual dimorphism Raptors 



We thank Kurt Elmqvist, Robert Franzén and Susanne Backe for assistance with blood sampling, and Sofia Berlin and Lori Lawson-Handley for discussions. Hans Ellegren, Ruth Tingay and Ülo Väli provided useful comments on a previous version of this manuscript. Hans Ellegren provided financial and logistical support. FH was supported by grants from Alvin’s Foundation, the Sven and Lilly Lawski Foundation and the Knut and Alice Wallenberg Foundation. Blood was sampled within the Swedish Society for Nature Conservation´s “Project Sea Eagle” with appropriate permits from the Swedish Board of Agriculture (licenses no. 35-3482/97, 35-4927/02) and from the Ethical Review Committee under the Swedish Animal Welfare Agency (licenses no. N66/97, N21/00, N262/02).


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Copyright information

© Dt. Ornithologen-Gesellschaft e.V. 2007

Authors and Affiliations

  1. 1.Department of Contaminant ResearchSwedish Museum of Natural HistoryStockholmSweden
  2. 2.Department of Evolutionary Biology, Evolutionary Biology CentreUppsala UniversityUppsalaSweden

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