Re: Rescued/Released Baby Birds Learn Songs?
Ellen Paul (epaul@dclink.com)
Mon, 01 Jun 1998 18:22:43 -0700
Dear Leslie and Ospreyers:
Some of the basic research on song learning was conducted by Peter
Marler in the classic isolation experiments in the 70's. Two of the
dozens of references are:
Marler, P. 1970. A comparative approach to vocal learning. Song
development in White-crowned Sparrows. J. Camparative Physiology and
Psychology Monographs. 71:1-25.
Marler, P. 1987. Sensitive periods and the roles of specific and
general sensory stimulation in birdsong learning. In: J.R. Rauschecker
and P. Marler, eds., Imprinting and Cortical plasticity: Comparative
aspects of Sensitive Periods. John Wiley and Sons, Inc., New York, pp.
99-135.
Eales, L.A. 1985. Song learning in zebra finches. Some effects of song
model availability on what is learnt and when. Anim. Behav.
33:1293-1300.
All sorts of variations have been done on the theme - tape tutors v.
live, audio tutelage v. audio-visual, cross-species tutors, manipulation
of photoperiod, related tutor v. unrelated tutor, and so on.
Keep in mind that cowbirds learn to sing cowbird song even though the
song they are most often exposed to is that of the host species! There
is experimental evidence that their songs are formed by the preferences
of female cowbirds. The females encourage or react to males singing the
"correct" song with something called a wing stroke. Other males will
learn to copy the males that provoke the wing stroke. Whether this
occurs in the critical period or at some later time is not clear.
Critical period affects a number of other behavioral traits, too.
Species imprinting occurs during this time. I strongly recommend a book
by David Butler and Don Merton called The Black Robin. It is a
compelling and fascinating account of their effort to save the Chatham
Island Black Robin using, at least in part, cross-fostering techniques.
They learned that they had to remove the young from the foster bird's
nest (the foster bird was a different species) before the critical
period, or the robins would grow up thinking they belonged to the other
species and would only want to mate with the other species. That also
happens to Rose-breasted Cockatoos in Australia. They are quite
prolific and can dump their eggs in the nests of other cockatoos,
including the Leadbetter's. The young rosies raised in the Leadbetter's
nests flock with the Leadbetter's and may even mate with them, as
apparent hybrids have been seen. (The Black Robin is Oxford University
Press, 1992, ISBN 0-19-558260-8; pricey even in paperback but well worth
the cost; I'm pretty sure Buteo Books has it in the catalogue).
Of course, the other major reference is Vol 2 of Accoustic Communication
in Birds - Song Learning and its Consequences. Edited by Donald E.
Kroodsma and Edward H. Miller. Academic Press 1982, ISBN 0-12-426802-1.
I think there may be a second edition out now.
Please don't misunderstand my comment about the ability of released
birds (songbirds or otherwise) to join breeding populations. The
question isn't whether they can, but what value does it have? (Although
if they don't have much breeding success, the second question is moot).
probably none.
At that point, you get into a question of personal preference and
decisions. I don't feel I have any right to comment on anyone else's
choices in this regard. I can state the reasons for my own decision and
offer to share information, but as long as you are making an informed
decision, that's all that matters. I really didn't mean to discourage
you. People who have chosen to do rehab have their reasons and I'm sure
they are valid. The fact that it isn't a perfect solution, or may not
be a solution to the problem you thought you were working on, just means
that you should re-examine your involvement, but it doesn't mean that
you should be discouraged or give up something that is meaningful to
you.
Ellen Paul
Chevy Chase, Md
epaul@dclink.com
mdosprey@ARI.Net wrote:
>
> Ellen Paul wrote:
> <
> I say this only because of your concern about the time and money going
> to save these birds. I was very interested in rehabbing at one point,
> then realized that my time and money could be going to species survival,
>
> rather than survival of individuals. I don't mean to criticize those
> who feel otherwise, but simply wanted to address your concern in the
> context of the "bigger picture."
>
> If you would like, I can provide a list of references on song learning.>
>
> Ellen, Thanks for your informative response. Yes, I wold be interested
> in the song learning references. I`m going to ask some of the higher
> ups @ Tri-State what they know about released songbirds being able to
> join breeding populations. This is very interesting to me, and somewhat
> discouraging too.
> Thanks, Leslie Fisher
--
Ellen Paul Chevy Chase, Maryland Mailto:epaul@dclink.com