Willow Flycatcher nonbreeding territory defense behavior in Costa Rica

The Condor
By: , and 



We studied the intraspecific territorial defense behavior of wintering Willow Flycatchers (Empidonax traillii) in Costa Rica using a randomized playback experiment that exposed male and female birds to recordings of Willow Flycatcher songs and calls, Lesser Ground Cuckoo (Morococcyx erythropygius) vocalizations, and random noise. Flycatchers of both sexes responded most strongly to simulated conspecific territory intrusion, and the agonistic behaviors that we observed were similar to those seen during natural intraspecific encounters in winter. Both males and females engaged in song and aggressive behaviors in defense of territories, and there was no significant difference between the sexes in scored agonistic responses. The similarity between the sexes in intraspecific territorial defense behaviors and aggressiveness may account for both sexes of flycatchers using the same habitats at our study sites in Costa Rica, and wintering females defending territories against males. The Willow Flycatcher, a sexually monomorphic species, differs in this way from a number of sexually dimorphic passerines, in which behaviorally dominant males occur in more optimal winter habitats. ?? The Cooper Ornithological Society 2007.
Publication type Article
Publication Subtype Journal Article
Title Willow Flycatcher nonbreeding territory defense behavior in Costa Rica
Series title The Condor
DOI 10.1650/0010-5422(2007)109[475:WFNTDB]2.0.CO;2
Volume 109
Issue 2
Year Published 2007
Language English
Larger Work Type Article
Larger Work Subtype Journal Article
Larger Work Title Condor
First page 475
Last page 480
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