I can offer some behavioral insights on the observations made by John
Thompson about Acadian Flycatcher vocalizations that will be useful for
others, especially since Acadian Flycatchers are expanding their
breeding range into large woodlands beyond the Carolinian Zone in
Ontario. For nearly a decade from 1997 to 2006, I and a few colleagues
did surveys for Acadian Flycatchers for the Acadian Flycatcher / Hooded
Warbler Recovery Team in southwestern Ontario.
1) Birds “singing quite frequently", especially in July are unmated males.
2) Birds making a "peculiar twittering sound while fluttering from perch
to perch" are without-a-doubt unmated males. These males sing briefly or
for some time from one perch but when they move to a new perch they make
the twittering call just as they land on the new perch and before
resuming the "see-slip" or 'peet-sa" call.
3) If you approach a singing male closely and he continues to sing, he
is unmated.
4) If you approach a singing male and he shuts up, then he is mated and
the active nest is nearby. If you get too close, then he will start
chipping to alert the female. If you get too close to the nest, the
female will also start to chip. Obviously, that is the time to back off.
5) Unmated males sing endlessly, even well into the afternoon. Mated
males sing periodically and sometimes not for long periods, especially
if there is only one territory in the woodland. Since he is already
mated and there are no other territorial males nearby, he has no need to
sing. In a woodland with several mated pairs, the males need to continue
to sing, but not twitter, to delineate their territories.
Dave Martin
Harrietsville, ON
damar...@xplornet.com
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