Kathleen Hunt posted re. high-pitched vocalizations from a robin. (Sorry
this mailer app won't do quoting): It has been my experience that this is
restricted to the female of the species. I have encountered it three times
and during two of those, there was a female Brown-headed Cowbird in close
proximity. I believe that this is some kind of agonistic response, perhaps
to a perceived threat. I, too, was searching for a long time during my
first encounter trying to find the source of the sound...and indeed it
turned out to be right above my head. This is similar to Flammulated Owl in
which a calling owl sounds a long way away but in almost all cases is much
closer to the listener than thought. In other words, it is not a
frequency-specific effect since the calls are on the opposite ends of the
human hearing range.

- Jack

Jack Bowling
Prince George, BC
jcbowling at mindlink.bc.ca