This June has been very interesting, with regard to Black-billed Cuckoo (and, to a lesser degree, Yellow-billed Cuckoo) movement and vocal activity during night migration over Etna, NY.
I continue to record calls from different individuals at higher rates compared to June of last year. According to papers published by Walter Koenig, cuckoo abundance increases on the year of 13- and 17-year Magicicada emergences, based upon analysis of BBS data. There is no longer emergence of the Magicicada broods in our immediate area (I believe these went extinct); however, there has been abundant emergences to our South and East (110 miles away and 132 miles away, respectively). If cuckoos have a tendency to wander actively in search of cicada emergences or caterpillar outbreaks (Malacosoma or Lymantria larvae) – which could be advantageous to both adult and nestling cuckoos – it would make sense that cuckoos are significantly more abundant as night migrants this June because of the relatively nearby emergence of the 17-year cicadas. Here is an updated link to the call counts for 2013 as well as the link for last year's call count data: 2013: http://www.northeastbirding.com/Cuckoo/2013Cuckoo.jpg 2012: http://www.northeastbirding.com/Cuckoo/2012Cuckoo.jpg There have been some proposals that these night vocalizations (grand majority being "gurgle" night flight calls) could be coming from local birds calling from immediately nearby locales or while perched in trees. This is an interesting thought, but seems unlikely for several reasons: 1) Most calls are often individually different from one another (frequency and cadence differences; also, two different birds have even been heard calling simultaneously on a few occasions) 2) Birds are sometimes heard clearly producing a sequence of 2-3 calls in passage (doppler shift) 3) If this many different birds were present locally, one would expect fairly high numbers being reported in eBird or commonly reported as sightings, posted on the local birding eList. Attached are some examples showing just how audibly different these birds have been. Spectrographically, the calls are measurably different as well. Thanks for any comments! 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/ --
2013BBCuckooVariability.wav
Description: 2013BBCuckooVariability.wav
