flight calls & flock habits, N. Boulder Cnty

[Linda Andes-Georges]

Hi folks--

I'm looking for some information on an occurrence that I noticed this morning while transecting in a closed County property.

I had been hearing Hermit Thrushes (singing, which is easy for me) and Spotted Sandpipers, all stationary. But just as I began trudging back to my car (thoroughly drenched, and tired of carrying scope with its gerry-rigged plastic bag protections), I saw a flock of about 20 birds, widely spaced, fly over me uttering a few scattered cries that I did NOT recognize. The light was terrible, and I had on a noisy nylon hood. Excuses aside, I could not decide if these were more Spotties or the Swainson's thrushes that others have seen in such numbers the past couple of days.

I've listened to a number of recordings, and lean toward the SPSAs.

Any comments? Do either or both species flock this way? They were headed east, downriver, exactly toward where Scott S was about to report big numbers of the SWTH.

I'd like to learn something from this puzzlement.

Linda Andes-Georges
Central Boulder County

PS joining all the other FOS reports, I had my FOS-Colorado Dusky flycatcher today. Most others have been previously reported by others.