Assertion: chickadee's song | /r/HasProperty | learned
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text: Laboratory experiments by Donald Kroodsma (Smith 1991) have shown that the song is learned, not innate, and field observations show that chickadees in the contact zone respond to playback of recorded songs of both species (Merritt 1978).
text: Calls are also learned, but apparently not in the same way that song is learned, e.g. at that same study site in Pennsylvania, calls are intermediate between Black-capped and Carolina, but birds giving more Carolina-like calls do not necessarily use Carolina-like songs.