کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
---|---|---|---|---|
2427901 | 1105984 | 2008 | 10 صفحه PDF | دانلود رایگان |
Acoustic frequency (pitch) cues are known to be important in the recognition of conspecific song in a number of songbird species. Mountain chickadees (Poecile gambeli) and black-capped chickadees (Poecile atricapillus) are sympatric over parts of their ranges and their species-typical songs share many features. I examined the acoustic characteristics of song of these two congeners in a region of sympatry in southern Alberta, Canada. As reported for other populations in allopatry, black-capped chickadees emphasized relative frequency cues in song production. In particular, variation in the ratios between note frequencies was significantly less than variation in the note frequencies themselves. In contrast, songs of mountain chickadees did not have constant frequency ratios and contained an introductory acoustic element absent in black-capped chickadee song. Both species may rely on song note frequency or the presence of this introductory acoustic element when differentiating between conspecific song and heterospecific song. Song measures for chickadees in sympatry were similar to measures in allopatry, providing little evidence for character displacement in song production.
Journal: Behavioural Processes - Volume 77, Issue 2, February 2008, Pages 156–165