Hi Tweets,

Again, the 'Robin' thread proves one should take nothing for granted; the
'eeer' call of the American Robin is something I had thought commonplace
for years because I've heard so many AMRO do it so often.

The first encounter was in springtime in the mid-Seventies, during a
fruitless search in park shrubbery for a Cedar Waxwing giving an odd call;
never could find the waxwing but I noticed this robin was always in the
vicinity whenever this call came slithering through the foliage. Finally
the penny dropped, and I watched the robin uttering the call, invariably
with closed bill. The bird itself was motionless, cagey and taut, not
wanting to be seen as the call's author.
The circumstance in which I've seen them utter this call is invariably (so
far) a low level nest defense when a perceived threat to the nest (usually
a foraging crow, housecat, cowbird, or--in the above case--human) is in the
vicinity--but not at--the nest, doesn't know it's there, and there's a fair
chance that the parent AMRO can spoof it away out of the area. Coupled with
the bird's immobility, the call's ventriloquial quality and slight
resemblance to a begging or alarm call serve to distract and lure away the
potential predator. Over the years, I've only seen the males utter the
call, females presumably being on the nest, and silent.

Why they'd call similarly in winter I don't know. Something to do with
winter feeding territory defense?

Cheers

Michael Price "Are you being brilliant or are you going
berserk?
Vancouver BC Canada At first, sometimes, it may be hard to
tell."
mprice at mindlink.net -New York Times
headline

--
Michael Price "Are you being brilliant or are you going
berserk?
Vancouver BC Canada At first, sometimes, it may be hard to
tell."
mprice at mindlink.net -New York Times
headline