The notion of playbacks to nesting songbirds is interesting. There are a
number of studies demonstrating that nesting songbirds can discriminate
between the songs of nesting neighbors and the songs of floating males
(i.e. those individuals who are seeking territories and present the
greatest threat). Typically, the resident nesting male responds much more
aggressively to unknown intruders, as opposed to established neighbors with
whom boundary conflict have already been resolved. This "dear enemy" effect
could possibly be used as a management technique to permit birders to
playback songs of local individuals, which may reduce disturbance to birds
in the playback arena.

Unfortunately one general problem with playbacks is that those recordings
that elicit the greatest response from a bird are generally the most
pleasurable for the bird watcher (i.e. the bird approaches more closely and
increases the intensity of its vocal and visual displays). However, this
is precisely the type of response that is most costly to a bird in terms of
energetic costs, predation risk, perhaps reduced provisioning of the young
and habituation effects.

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Behavioral Ecology Research Group
Dept. of Biological Sciences
Simon Fraser University
Burnaby BC V5A 1S6 Canada
phone: (604) 291-4374 Lab
291-5864 Office
fax: (604) 291-3496
email: fsharpe at sfu.ca
Alaska BC Whale Foundation webpage:
http://www.biol.sfu.ca/berg/whale/abcwhale.html