Hi everyone, I would lean toward local movements, rather than northbound migration, as the mechanism behind most of the observations mentioned in this thread. Among freshwater ducks, facultative dispersal is often conspicuous throughout the winter on Long Island, where unfrozen salt water is almost always just a short flight away from the ponds preferred by the various species. On the weekend before last, Tom Burke and we were only slightly surprised to find that most of 250 scaup out on Great South Bay were Lessers, rather than Greaters, which are usually the numerous species on the open salt bays. Nearby were many excellent Lesser Scaup ponds, which had recently re-frozen. Similarly, last weekend, Dick Veit and we were not very surprised that a lone scaup on the Atlantic Ocean near Shinnecock Inlet was a Lesser. When their preferred ponds freeze, even Common Mergansers will resort to the ocean at times (http://picasaweb.google.com/tixbirdz/Various2009#5420408466155755842).
Regarding vultures, I've seen winter roosts in southern New England still cohering as late as late March. The big spring vulture flights on Lake Ontario occur in early April, and even in Veracruz, Mexico, the peak flights occur in late March. As Steve notes, snow cover could be a factor influencing local movements for these species, as it clearly is for many raptors. These things are on my mind because we are just about to do our Presidents Day Count out on Block Island, where we have been bracketing the CBC with similar effort in November and February since 1996--with the goal of disentangling dispersal, migration, and mortality as mechanisms underlying changes in bird abundance. A quick search through these data for species occurring in larger numbers in Feb than Dec reveals a hint of hard weather dispersal (slight upticks for a few freshwater ducks, raptors, and marginal winter species, such as Greater Yellowlegs. Only Red-winged Blackbird and Common Grackle are obvious northbound migrants (although a few scarcer species, notably Wood Duck, might also belong here rather than in the previous category). But the most obvious examples of species that consistently increase in abundance between Dec and Feb are Common Goldeneye, Oldsquaw, Horned and Red-necked Grebes, Great Cormorant, Common Murre, and Black Guillemot. Most of these species are scarce to absent in Nov, pick up a little bit in Dec, then increase markedly by Feb (Oldsquaw and Great Cormorant are the exceptions, being common in Nov, holding steady in Dec, then surging in Feb). If you are a fan of the CBCs, it might be fun to spend a day next weekend covering your favorite territory the way you did in Dec. Shai Mitra Bay Shore, NY ________________________________________ From: bounce-5236294-11143...@list.cornell.edu [bounce-5236294-11143...@list.cornell.edu] On Behalf Of Steve Walter [swalte...@verizon.net] Sent: Monday, February 08, 2010 5:51 PM To: NYSBIRDS-L@cornell.edu Subject: Re: [nysbirds-l] Brooklyn - Black Vulture "Is this a migrant, already?" is my question of the day, too. My subject was a Common Merganser on Oakland Lake, Queens, where the species only occurs as a spring migrant. But things could be shuffling around because of ice (Oakland Lake itself is two-thirds iced up (interestingly, a lone Lesser Scaup appeared there last week)) or snow. I've noted Rough-legged Hawks and other raptors coming our way in past years (around late January) after significant snowfalls to the north. It would be a strange twist if the vultures appearing to be headed north are evacuating the big snowfall that fell to our south. Steve Walter Bayside, NY ----- Original Message ----- From: fresha2...@aol.com<mailto:fresha2...@aol.com> To: NYSBIRDS-L@cornell.edu<mailto:NYSBIRDS-L@cornell.edu> Sent: Monday, February 08, 2010 1:13 AM Subject: [nysbirds-l] Brooklyn - Black Vulture Yesterday (Sunday, 2/7) just after 1:00 PM a Black Vulture coasted northwest over Prospect Park lake flying extremely high, and almost exclusively soaring. I know Turkey Vultures start migrating in February, but it is still pretty early in the month, and Black Vultures aren't yet common in the area (they're still downright rare in Brooklyn, even in peak migration) so it came as quite a surprise to me. It certainly looked like it was exhibiting migratory behavior. There were also ~1600 Ring-billed Gulls (counted and examined closely), including wing-tags A318 (a repeat) and A288 (a new one for me). Good Birding -Doug Gochfeld. Brooklyn, NY. Think green before you print this email. -- NYSbirds-L List Info: http://www.NortheastBirding.com/NYSbirdsWELCOME http://www.NortheastBirding.com/NYSbirdsRULES ARCHIVES: 1) http://www.mail-archive.com/nysbirds-l@cornell.edu/maillist.html 2) http://birdingonthe.net/mailinglists/NYSB.html 3) http://www.surfbirds.com/birdingmail/Group/NYSBirds-L Please submit your observations to eBird: http://ebird.org/content/ebird/ --
