On Sat, Nov 15, 2003 at 10:06:42PM +1000, jade welch wrote:
> I have a question to ask. My question is this. When birds are raised by
> other species such as with cuckoos do the birds use some or all of the
> calls of their hosts through out there life and if not how do they learn
> the calls of their real parents?
Most bird vocalizations are partly or completely genetically determined
(inherited). In the passerines and some other groups environmental
influence (vocal learning) is known to be important.
Some bird species when raised without hearing parental or other
conspecific vocalizations will still develop normal vocalizations.
Some species raised in such isolation develop vocalizations missing
elements or differing in other attributes. Some species will not develop
anything resembling normal vocalizations.
I haven't seen any mention of vocal learning in the Cuculidae (Cuckoos).
If vocal learning is present you'd expect to see to see geographical
variation in vocalizations. My impression is that some Australian
cuckoo species' vocalizations don't vary across their range. If so,
it is likely that their vocalizations are entirely genetically determined.
I think some Australian cuckoos, e.g. Pallid Cuckoo, do vary
geographically - I expect others on this list could make more confident
statements. If so vocal learning may (or may not) be present.
Learning of the foster-parent's vocalizations is known from passerine
brood parasites such as the indigo-birds. Male indigo-birds are also
know to learn from other male indigo-birds after fledging.
In another passerine brood-parasite, the Brown-headed Cowbird, young males
have been shown to adapt their songs on the basis of female preferences
communicated via visual signals.
Learning of foster-siblings begging vocalization could have adaptive
value for cuckoo and other brood parasite fledglings but I haven't seen
any mention of this.
Andrew
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