-----Original Message----- From: pjdeye <pjd...@aol.com> To: cth4 <c...@cornell.edu>; nfc-l <nfc-l@cornell.edu> Sent: Wed, Sep 25, 2013 4:02 pm Subject: Re: [nfc-l] Migration 9/23-9/24 - HF Gray-cheeks
Hi Chris, I'd like to open up a discussion on Bicknell's Thrush calls. There was a discussion on xeno-canto recently in which there was some questioning of the validity of the nocturnal calls as there is so much variability and overlap between Gray-cheeked and Bicknell's daytime calls, more recordings of which are now available. That not withstanding, I have yet to see a daytime recording of a known Gray-cheeked that matches the Bicknell's nocturnal call. Isn't it likely that the Bicknell's call is only one of many different calls Bicknell's make at night, but perhaps the only one that is definitive? Or perhaps it's a call that Bicknell's uses more than Gray-cheeked ie there is a quantitative difference in their calls? There was also a suggestion that perhaps they are not truly separate species (so perhaps all this is moot). I recorded several calls last night that match Bicknell's quite well. These are the first calls I've recorded so far this season that have that appearance, and were several different birds. All others (100s) going back to September 15th had been typical lower frequency "buffalo-humped" Gray-cheeked. To me, this suggests that there is a certain defined population that gives this less common call. Paul Driver Elkins Park PA -- 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/ --
poss_bick_3.45am_(2).mp3
Description: audio/mpeg
poss_bick_4.44am_(2).mp3
Description: audio/mpeg
poss_bick_5.46am_(2.1).mp3
Description: audio/mpeg
poss_bick_5.50am_(2).mp3
Description: audio/mpeg
