Hi, all. I ponder this question a lot. In all my experience in Colorado, I have heard exactly one (1) flight call from a robin that seemed to be an on-the-go nocturnal migrant. (For comparison, I've heard more flight calls from nocturnal-migrant Western Grebes and Eastern Kingbirds in Colorado.) I've flushed a lot of robins by night, but that doesn't really count. In Boulder County, Colorado, then, I'd say that robins are practically silent as nocturnal migrants, or they simply do not migrate by night. I frequently see (and hear) heavy, medium-altitude robin passages that go strong right to around sundown, but then the flights suddenly end at nightfall. Daytime "Vis Mig" of American Robins is striking (visual and audible) in the Front Range region of Colorado, comparable to the heavy daytime flights of Common Grackles in early spring. Ted Floyd tfl...@aba.org Lafayette, Boulder County, Colorado
________________________________ From: bounce-5534264-9667...@list.cornell.edu [mailto:bounce-5534264-9667...@list.cornell.edu] On Behalf Of Michael O'Brien Sent: Tuesday, April 06, 2010 1:59 PM To: Jeff Wells Cc: NFC-L@cornell.edu Subject: Re: [nfc-l] Night flight call station results-Maine-April 1-3 Jeff, I'm interested in your assertion that American Robin is strictly a diurnal migrant. Perhaps that is true in some areas, but in Cape May it certainly is not. We regularly see massive American Robin flights at night, in fall at least. These flights often continue or resume in the first few hours of the morning and again in the last hour or so of the day. During particularly heavy flights, the movements may continue longer into the day, but my estimation is that the bulk of the movement always takes place at night. I find their behavior to be much like that of Bobolink, only they seem to be less vocal. It would be interesting to know what others have observed and if the situation is different elsewhere. My guess is that the main difference, if any, is that robins call more frequently in certain situations and fly more quietly in others. good listening! Michael O'Brien ----- Original Message ----- From: "Jeff Wells" <jwe...@intlboreal.org> To: NFC-L@cornell.edu Sent: Tuesday, April 6, 2010 2:42:45 PM GMT -05:00 US/Canada Eastern Subject: [nfc-l] Night flight call station results-Maine-April 1-3 I started my automated recording station for the season here in Maine on Thursday night, April 1st. Although there were few calls each of the last three nights, the numbers increased a little each night from about 10 the night of the 1st to about 30 last night. There were a few Hermit Thrushes the first night, 6 the 2nd and 12 the night of the 3rd. There were a few Killdeer each night, a Wood Duck, and 4-10 sparrows each night with Song and White-throat plus a couple that may be American Tree Sparrow and a junco or two. A few other items of interest: -several nights had Herring Gull calls in the middle of the night that I assume are night migrating birds; -several nights had the squeal flight calls of American Robins around midnight. Although I sometimes have what I assume to be local on-the-ground robins sing and give ground alarm calls in the middle of the night, they don't give the squeal calls. The acoustics of the recorded squeal calls also seem more like birds overhead. I suspect that, as unlikely as it seems, that these were night-flying robins when by all accounts the species is only a diurnal migrant; -one night I had what sounded like a bit of song of a night-flying Hermit Thrush. I typically get some night-flying birds in May that break out in song or partial song while flying overhead but I had never picked that up for Hermit Thrush. I posted some of the call files on my blog at: www.borealbirds.org/blog Jeff Wells -- 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/ --
