Hi all: I've recently read most of the posts about the McIntosh loon and nocturnal flights of migrants and had a few things to write in response. First off, the pattern that I see in Ted's Upland Sandpipers-over-Boulder data, is that insomniacs detect more nocturnally-migrating Uppies than do most other birders. I mean, I'm almost always up around 11:30 pm, but only rarely so after 2 am. Thus, I hear very few Uppies going over, Boulder or elsewhere.
Mostly, though, I wanted to comment on the debate about the McIntosh Res. Pacific Loon and loon flight-feather molt. What and why? All loon species (and presumably individuals) conduct a complete flight-feather molt each year, with the timing of such varying between ages and species. Like waterfowl, loons drop all of their flight feathers at once (or very nearly so), becoming flightless for a fairly substantial period (1-2 months). It is believed that this benefits these species more than a more-typical-for-birds slower and staggered flight-feather molt, as it reduces the time during which flight is impaired by missing feathers. Yes, their flight gets supremely impaired with no flight feathers, but it works. There just aren't a lot of predators out on the open water that can tackle a bird the size of a loon. It should also be noted that it would behoove a species that finds it necessary to use its wings in foraging to NOT drop all of its flight feathers for such a long period of time. Loons do not use their wings under water, rather using their somewhat outsized feet to propel them. Where and when? On the East Coast, Common and Red-throated loons are both common and widespread migrants and winterers, but they have very different strategies to dealing with timing their flight-feather molt. Adult Common Loons migrate away from breeding grounds in alternate plumage, arrive on winter grounds, and commence their pre-basic molt, which includes flight feathers. On the other hand, Red-throated Loons conduct their pre-basic molt on or near the breeding grounds, arriving on wintering areas in basic plumage and with their flight-feather molt already completed. Thus, if one goes out on the ocean in winter, all of the Red-throated Loons fly away, and most of the Commons dive or patter off with their useless wings rowing them along. Note that, above, I wrote that "most of the Commons." This is the smooth segue to the variance among ages of timing and/or location of the flight-feather molt. First-year Common Loons primarily stay on the winter grounds during their first summer, conducting their pre-basic molt, which includes their flight feathers. Most young Red-throated Loons depart NJ latitudes for points north or elsewhere and, presumably, conduct their pre-basic molt (including flight feathers) nearer the breeding grounds. My lifer Pacific Loon was a summering bird in New Jersey, lo these many years ago, that was conducting its flight-feather molt, was ragged, and very much (in some regards) disappointing to one hoping to see a stunning bird. The McIntosh Res. Pacific Loon is simply going through the normal processes of almost all other Pacific Loons: conducting its pre-basic molt on the safety of a larg(ish) body of water while killing time waiting to go to the breeding grounds next summer. Whether all or most young Pacifics follow the Common strategy or not, the Boulder Co. bird is in no way in more danger than is any of its conspecifics of that age. Having none of my references at hand here in Alabama, I cannot send you to particular passages or pages in certain references, but I would suggest checking out the various behavior and ecology bird books (Sibley's, Kaufman's, and the yellow-covered one whose authors' names I cannot recall right now) or even the old Audubon Encyclopedia of North American Birds (edited by John Terres). I would bet that it's all in there. Sincerely, Tony Leukering Villas, NJ P.S. Now is a great time to go out and find migrant Mourning Warblers!! -- You received this message because you are subscribed to the Google Groups "Colorado Birds" group. To post to this group, send email to cobi...@googlegroups.com. To unsubscribe from this group, send email to cobirds+unsubscr...@googlegroups.com. For more options, visit this group at http://groups.google.com/group/cobirds?hl=en.
