Pretty fascinating stuff- since the radar reflectivity did not indicate the 'largest' flight of the season for NY State, yet the call rates were clearly highest. The upper-level winds were out of the WSW last night, which may have caused 1) more birds to compensate for drift and 2) birds to fly at lower altitude to avoid the effects of the head/side wind. Whether 1 would influence call rate is unknown to me, but 2 should definitely influence the detectability of calls. We could test 2 by calculating the vertical profile of reflectivity for last night and several other of the 'big' nights over the last month- and see whether there is a significant difference. This would at least tell us whether the detected call rate had to do with the way we sample the sky (and the detectability of birds at various altitudes). Knowing the altitudinal distribution we could then look at the winds aloft to determine the relative effect (wind aloft from radiosonde balloons vs. actual target speed and direction derived from the radar) of the wind on flight direction, and therefore infer whether birds were being pushed off course. I guess there's a viable 3rd option which is that more immature (and naive) birds are flying now than earlier in the season, which we would assume would influence call rate... although I don't know the relative breakdown of adult:immature in the suite of species moving now (just thinking of Am Redstart is what conjured the hypothesis).
Any other thoughts? cheers David ________________________ David A. La Puma Postdoctoral Associate New Jersey Audubon Society 600 Route 47 North Cape May Court House, NJ 08210 Office: 609.861.1608 x33 Fax: 609.861.1651 Teaching/Research Profile: http://www.woodcreeper.com/teaching Websites: http://www.woodcreeper.com http://badbirdz2.wordpress.com Photos: http://www.flickr.com/photos/woodcreeper On Wed, Sep 21, 2011 at 9:55 AM, Bill Evans <wrev...@clarityconnect.com>wrote: > Ken appears to have tuned into one of the biggest calling night of the > season so far in central NY. The acoustic station at Alfred Station, NY > logged its season high number (988) of warbler and sparrow flight calls last > night between 8:30PM-5:30AM. Based on spectrographic analysis roughly 4 out > of 100 were Common Yellowthroat, 2 out of 100 were Black-throated Blue, and > 2 out of 100 were Chestnut-sided. Also notably in the mix were good numbers > of presumed Lincoln's Sparrow calls. > > Bill E > > > > > > > -- > > NFC-L List Info: > http://www.NortheastBirding.**com/NFC_WELCOME<http://www.NortheastBirding.com/NFC_WELCOME> > http://www.NortheastBirding.**com/NFC_RULES<http://www.NortheastBirding.com/NFC_RULES> > http://www.NortheastBirding.**com/NFC-L_**SubscribeConfigurationLeave.** > htm<http://www.NortheastBirding.com/NFC-L_SubscribeConfigurationLeave.htm> > > ARCHIVES: > 1) > http://www.mail-archive.com/**nfc-l@cornell.edu/maillist.**html<http://www.mail-archive.com/nfc-l@cornell.edu/maillist.html> > 2) > http://www.surfbirds.com/**birdingmail/Group/NFC-L<http://www.surfbirds.com/birdingmail/Group/NFC-L> > 3) > http://birdingonthe.net/**mailinglists/NFCL.html<http://birdingonthe.net/mailinglists/NFCL.html> > > Please submit your observations to eBird: > http://ebird.org/content/**ebird/ <http://ebird.org/content/ebird/> > > -- > -- NFC-L List Info: http://www.NortheastBirding.com/NFC_WELCOME http://www.NortheastBirding.com/NFC_RULES http://www.NortheastBirding.com/NFC-L_SubscribeConfigurationLeave.htm ARCHIVES: 1) http://www.mail-archive.com/nfc-l@cornell.edu/maillist.html 2) http://www.surfbirds.com/birdingmail/Group/NFC-L 3) http://birdingonthe.net/mailinglists/NFCL.html Please submit your observations to eBird: http://ebird.org/content/ebird/ --
