Thought I'd share the attached chart with anyone interested in these data. It would make sense that the first peak in migration are returning adults, while the latter hump in migration (in June) are first-year birds. I imagine, if this is the case, it can be supported by banding data.
Please note that these numbers are total calls recorded over the time-span of the 2012 migration season and do include minimal repetition of some individual Black-billed Cuckoos; in rare cases, individual Black-billed Cuckoos can audibly be heard (or seen via spectrogram) repeat their call frequently enough to be heard twice and, with extreme rarity, thrice. This year's numbers which I have posted to the eList do not include repetition of presumed "same" individuals; however, I am still keeping those audio data as examples. So far, I am not aware of Yellow-billed Cuckoos audibly being heard repeating singing bouts frequent enough to be heard twice in a short time-span, thus duplication is not evident for Yellow-billed Cuckoos. Enjoy! Sincerely, Chris T-H -- Christopher T. Tessaglia-Hymes Field Applications Engineer Bioacoustics Research Program, Cornell Lab of Ornithology 159 Sapsucker Woods Road, Ithaca, New York 14850 W: 607-254-2418 M: 607-351-5740 F: 607-254-1132 http://www.birds.cornell.edu/brp -- 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/ --
2012 Cuckoo Migration.pdf
Description: 2012 Cuckoo Migration.pdf
