Folks,

I don't know of evidence for crows postponing gratification in feeding
on nest contents, but nest-farming by cowbirds has been documented in
long-term Song Sparrow studies on islands in British Columbia. Cowbirds
have been observed to remove sparrow eggs from nests found after
incubation has begun, which gets the sparrows to start laying again,
making nests available for brood parasitism. I'm sorry I don't have a
citation to share at present.

Crows and cowbirds are cool,

Alan Grenon
Seattle
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