I got a close look today at an American Robin giving a vocalization that I
haven't noticed before. I got out of my car at UW, and while putting my
money in the meter (this can take quite a while!) I realized I was
hearing a thin, high-pitched, continually repeated descending note:
eeer,eeer,eeer,eeer. It was VERY thin, high-pitched, and faint, like a
nestling's begging call (I even thought, ridiculously, "nestling
mockingbird?"), and it dropped distinctly in pitch. Each call lasted about
1 second and the calls repeated every 2 seconds in an apparently endless
monotonous series.

After looking all around, I finally realized there was an American Robin
perched about four feet above my head, which meant the call was much
fainter than I had first thought. The robin was perched absolutely still
in a little tree. I stared at the bottom of its chin for several minutes
and was convinced that it wasn't the bird giving the call, because from
that angle it looked like its bill wasn't moving at all, and its throat
certainly wasn't moving. Then I stepped a few feet to the side and
detected that it was opening its bill a tiny bit (about 2 mm at the bill
tips) for each call.

It just sat there, stock still, at the end of the day in the fading
light, incessantly repeating this very faint, high-pitched descending
note. Why?

curious,
Kathleen