Andrew, To me this seems more like a Gray-cheeked Thrush. When I was at Powdermill in SW PA we routinely got Bicknell's in the fall (~10-20/ year). In Somerset, PA last fall I recorded several too, but have not fully analized the data yet to know exactly how many. This fall I have not heard any while listening, but I have not looked at any recordings yet to see if they are on them, it seems a bit on the early side though. The furthur east in PA the more likey you are to get them, our costral sites get quite a few and they decrease quickly as you head inland. To me this call fits Gray-cheeked pretty well. They can peak at 4.5, in fact we analyzed a lot that did. I have not done any stats specifically on Gray-cheek calls, but they are fairly variable in my experiance. Usually Bicknell's jump right out at you, they are quite a biut higher, peaking above 5kHz, and sometimes nearly to 6kHz. They also drop quickly after the peak before a deceding slope pattern. Gray-cheekeds can drop fast initially too in some of their variations, but its not as high and the drop is shorter in duration, also they still have a more averaged arched slope in the decent of their calls after the peak. The peak of Gray cheeked in some birds can also happen after the first third to in some cases half of their calls almost arching to and away from the peak, whereas the Bicknell's (at least in the calls I have seen) always peaks very early before the first quarter then decending evenly there after.
Michael Lanzone [email protected] On Mon, Sep 19, 2011 at 11:13 PM, Andrew Albright <[email protected] > wrote: > Early this morning, I recorded a nfc that's seems in between > Gray-Cheeked or Bicknell's Thrush. I checked through the archives of > this list and this topic doesn't seem to have been discussed to death. > > BAYESIAN INFERENCE > With several days of nice Northeast winds, I figured that Bicknell's > Thrush was possible to record in southeastern PA. Pennsylvania doesn't > have any ebird records of Bicknell's but New Jersey and Maryland seem > to be all in early October. Wilson and Watts, 1997 show that > Bicknell's is possible in the general area, but unlikely on Sept 19th. > Same with Birds of Pennsylvania with banding records starting on > Sept 20th. > > > SONAGRAM ANALYSIS > Gray-cheeked Thrush is much more common in general and on September 19th. > > The main sonagram of interest peaks over 4.5 kHz and nothing I can > find for Gray-cheeked are much more than 4.0 kHz. > Shape - seems to suggest Bicknell's from most published recordings > (except for the nocturnal page on the nfc CD) > > In the second set of sonagrams, I made a composite of 4 nfcs > 1) A nfc that looks like Gray-Cheeked Thrush, especially if I increase > the "y" axis of time. > 2) The main sonagram of interest (shown above). > 3) This call was right after the possible Bicknell's and I didn't cut > it out. It was weak but sounded like a Swainson's and maybe looks > more like Wood Thrush. > 4) Lastly is another higher pitched call that's seems like it may be > Gray-cheeked (except for the "M" shape). > > > EAR ANALYSIS > Listening to the nfc CD's recordings of Bicknell's and Gray-Cheeked > has me leaning toward Bicknell's. But this is pretty subjective and > maybe only because of the higher pitched recording. > > > Sincerely, > Andrew Albright > Maple Glen, PA > > > Weblinks to sonagrams of Gray-Cheeked and/or Bicknell's > > http://www.birds.cornell.edu/birdcalls/species/Thrushes/Gray-cheeked%20Thrush%20%28Catharus%20minimus%29/ > > http://www.nightmigrants.com/main/page_species_calls_graycheeked_thrush.html > http://pjdeye.blogspot.com/2009/02/thrush-calls.html (Recording of > Bicknell's in S.E. Pennsylvania) > > -- > > 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/[email protected]/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/ > > -- -- 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/[email protected]/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/ --
