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1 August 2011 Winter Distribution of Willow Flycatcher Subspecies
Eben H. Paxton, Philip Unitt, Mark K. Sogge, Mary Whitfield, Paul Keim
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Documenting how different regions across a species' breeding and nonbreeding range are linked via migratory movements is the first step in understanding how events in one region can influence events in others and is critical to identifying conservation threats throughout a migratory animal's annual cycle. We combined two studies that evaluated migratory connectivity in the Willow Flycatcher (Empidonax traillii), one using mitochondrial DNA sequences from 172 flycatchers sampled throughout their winter range, and another which examined morphological characteristics of 68 museum specimens collected in the winter range. Our results indicate that the four subspecies occupy distinct but overlapping regions of the winter range. Connectivity between specific breeding and winter grounds appears to be moderate to strong, with distributions that suggest migration patterns of both the chain and leap-frog types connecting the breeding and nonbreeding grounds. The Pacific lowlands of Costa Rica appear to be a key winter location for the endangered Southwestern Willow Flycatcher (E. t. extimus), although other countries in Central America may also be important for the subspecies.

© 2011 by The Cooper Ornithological Society. All rights reserved. Please direct all requests for permission to photocopy or reproduce article content through the University of California Press's Rights and Permissions website,
Eben H. Paxton, Philip Unitt, Mark K. Sogge, Mary Whitfield, and Paul Keim "Winter Distribution of Willow Flycatcher Subspecies," The Condor 113(3), 608-618, (1 August 2011).
Received: 17 October 2009; Accepted: 1 January 2011; Published: 1 August 2011

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