Hi all --
Jay Withgott in Portland, Oregon, here. I've been enjoying the listserve -- keep it coming, everyone.
A good nocturnal flight passed over Portland last night (22-23 Aug.). I heard a few Swainson's Thrush call notes overhead in the evening, then listened from 5-6 a.m. I estimated 116 Swainson's Thrushes in 52 minutes (with most individuals calling multiple times, thus several hundred actual call notes). This rate of 2.2 thrushes per minute makes for one of the better nocturnal flights I've heard here the last few falls.
The most amazing thing to me continues to be just how much this one species, Swainson's Thrush, dominates the nighttime chorus here (as opposed to the more species-rich flights in eastern North America, or those that Ted gets in Colorado). I even get more lop-sided results than Jim Danzenbaker, who is not too far across the river from me in Washington. For instance, this morning in those 52 minutes I heard only one bird (a warbler species) I could be sure was not a Swainson's Thrush. Part of the explanation for the domination of these flights by SWTH may simply be that my ears are not as good as Jim's or Ted's, but I have enough past experience from the eastern U.S. to know that the flights here in Portland are, in fact, notably depauperate in comparison. Another part of the explanation is probably that thrush calls are louder and thus more easily heard than sparrow and warbler calls. And in addition, as has been noted by others on this list recently, Western Tanager and Black-headed Grosbeak can apparently sound a lot like Swainson's Thrush, and all these species show quite a bit of variation.
I'd love to be able to deal more effectively at least with this latter issue, so if anyone out there has some good resources or recordings to help separate SWTH, WETA, and BHGR, I'd love to hear from you. I personally rarely hear anything at night that sounds like any of the daytime calls of WETA and BHGR; the great majority of audible calls really do seem to be wholly consistent with SWTH. But I continually question myself on this point and feel I must be missing something.
The peak of SWTH migration here tends to be in the first week of Sept., but it's looking like it may be a bit earlier this year. Happy listening and recording, all,
Jay Withgott Portland, OR -- NFC-L List Info: http://www.NortheastBirding.com/NFC_WELCOME http://www.NortheastBirding.com/NFC_RULES http://www.mail-archive.com/[email protected]/maillist.html --
