ma002a5887
Fri, 18 Dec 2009 15:29:03 -0800
Without thinking too hard,UK birds which can be aged as 1CY-2CY or adult using calls include Guillemot, sterna Terns, Herring Gull, LesserBlack-backed Gull, Chiffchaff and Linnet. I'm sure further thought would throw up more examples. Ross > Hi all, > Ah, the interesting directions to pursue! Great thoughts, Gerard, > Magnus, and Ross! > > Two thoughts/observations: > - first, Rose-breasted Grosbeaks produce calls that vary by age, and > it's likely that other species might as well. For grosbeaks, these > seem to coincide with discrete call types that differ rather > noticeably (by spectrogram and by ear) from one another in duration, > frequency, and note structure between juveniles and adults (in diurnal > and nocturnal migration) . . . > > - second, during my dissertation research and in collaboration with > Mike, Emma, Lewis, and the Powdermill Avian Research Center folks, I > found that there were subtle but statistically significant differences > in various call measurements by age and sex in some species of Parulid > warblers; these data come from recordings of captive birds (a la > Lanzone et al. 2009 in the July issue of Auk), so whether this has > practical or biological relevance or application remains to be seen > (we're talking potentially highly esoteric subtlety in the machine > learning/statistical sense rather than subtle but clearly audible > difference typical of some species' complexes to trained field > observers). I suspect that this subtlety, no matter how you describe > it, would be mostly lost in the typical types of recordings that we > make of passing, vocal nocturnal migrants - so, I won't be the one to > shoot down Magnus!!! > > Regardless, I hope to publish this warbler work at some point in 2010 > or 2011, but I can make available the chapter to those interested. . . > > Best, > Andrew > > On Fri, Dec 18, 2009 at 11:23 AM, SLIMBIRD Gerard <gphill...@istar.ca> > wrote: >> A related discussion which Iâm sure many on the list might be >> interested in >> learning more about in general is flight call variation of adult verses >> juvenile birds. Any known examples of North American species that give >> distinctive age related flight calls either diurnal or nocturnal? >> >> Sincerely, >> Gerard Phillips >> Ontario, Canada >> >> On 12/17/09 10:48 AM, "Andrew Farnsworth" <andrew.farnswo...@gmail.com> >> wrote: >> >> variation may exist among calls given in migration, non-breeding, and >> post-breeding seasons, and on and on >> >> > > Itâs bordering on pure speculation and is only just relevant to this > group, but I have a sneaky suspicion the alarm calls of Blackbird are > sexually dimorphic. Iâm collecting recordings at the moment to find > out. > > Cheers > Ross Ahmed > > > From: bounce-4786788-10116...@list.cornell.edu > [mailto:bounce-4786788-10116...@list.cornell.edu] On Behalf Of Magnus > Robb > Sent: 18 December 2009 17:04 > To: nfc-l@cornell.edu Call ListServe > Cc: Andrew Farnsworth; SLIMBIRD Gerard > Subject: [nfc-l] passerines with sexually dimorphic flight calls? > - Hide quoted text - > > Equally interesting is the question of which passerines (and > 'near-passerines') can be sexed according to their flight calls > outside of the breeding season. I have not searched for examples in > any thorough way, although I have been recording migrants and noting > sex when possible for a long time, without noticing examples. During > spring migration, some birds may sing while passing overhead, and > depending on the species, this might be limited to males. Limiting the > discussion to flight calls, however, I can only think of Raven as a > passerine known to have at least some male- or female-only calls > throughout the year. There are many more examples among > non-passerines, eg Apus swifts, but most passerines seem to share > non-breeding call repertoire across the sexes without noticeable > differences. > > I would be delighted to be shot down and shown that there are many > examples, but what are they? Alternatively, are there instances of > some passerine species where males use certain shared calls much more > often than females outside the breeding season? > all the best, > > Magnus Robb > > -- > > NFC-L List Info: > http://www.NortheastBirding.com/NFC_WELCOME > http://www.NortheastBirding.com/NFC_RULES > > Archives: > 1) http://www.mail-archive.com/nfc-l@cornell.edu/maillist.html > 2) http://birdingonthe.net/mailinglists/NFCL.html > 3) http://www.surfbirds.com/birdingmail/Group/NFC-L > > 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 Archives: 1) http://www.mail-archive.com/nfc-l@cornell.edu/maillist.html 2) http://birdingonthe.net/mailinglists/NFCL.html 3) http://www.surfbirds.com/birdingmail/Group/NFC-L Please submit your observations to eBird: http://ebird.org/content/ebird/ --