Nestling sex ratios in the southwestern willow flycatcher

By: , and 



Using molecular-genetic techniques, we determined the gender of 202 Southwestern Willow Flycatcher (Empidonax traillii extimus) nestlings from 95 nests sampled over a five-year period. Overall nestling sex ratio did not vary significantly from 50:50 among years, by clutch order, or by mating strategy (monogamous vs. polygamous pairings). However, we did observe significant differences among the four sites sampled, with sex ratios biased either toward males or females at the different sites. Given the small population sizes and geographic isolation of many of the endangered subspecies' breeding populations, sex-ratio differences may have localized negative impacts.

Publication type Article
Publication Subtype Journal Article
Title Nestling sex ratios in the southwestern willow flycatcher
Series title Condor
DOI 10.1093/condor/104.4.877
Volume 104
Issue 4
Year Published 2002
Language English
Publisher Oxford Academic
Contributing office(s) Forest and Rangeland Ecosystem Science Center
Description 5 p.
First page 877
Last page 881
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