Greetings All
Tony did a bang-up job in discussing vagrancy potential, especially mega-vagrants. Pink-footed Goose, for instance... though thousands of miles out of range in WA, PF Goose is a species that is a long distance migrant, and might well find good forage in mid fall in central Alberta along the way to WA. And remember, it is thought that a fair number of vagrants go precisely (or nearly so) 180 degrees the wrong way, due to genetic errors, or acquired navigational issues. And that is the direction, if those geese in WA were wild, they would've taken. They are a good example of an occurrence that is nearly impossible to confidently say "Yea" or "Neigh" re: origins. A different example is set by Emperor Goose: a few heady Emperor Geese are known to cast themselves southward along the Pacific Coast annually, and their occurrence (by and large) fits a neat pattern consistent with a natural pattern of occurrence. The long-ago record of Baikal Teal in CO sets forth a conundrum similar to that with the PF Geese. AT THE TIME, Baikal Teal were in a tremendous population decline, records in AK had essentially gone to zero, and the species is popular in collections. My personal bias is that I would not consider that bird of natural origin. But it might have been. And for those agitated by listing, it is your list, count what you feel good about. The duties of BRCs do not delineate what an individual puts on one's personal list. A Baikal Teal occurring now would be viewed differently. The number of records in AK have exploded concurrently with the population explosion in Asia, and so has the number of vagrant Baikals on the Pac Coast from WA to CA. Context is ever so important in making the best possible decision (while recognizing that such decisions could still be erroneous). However, the birds mentioned in the statement below are quite different. The relationship between their occurrence and that of the Rufous-collared Sparrow is naught: Reddish Egret at DeWeese, Sooty Tern in Pueblo, Little Gull in Gunnison, Ross' Gull in Aurora, Streak-backed Oriole in Loveland, Eurasian Wigeon in Fort Collins, and all sorts of things that made no sense. To include Reddish Egret, Little Gull, Ross's Gull, and Eurasian Wigeon in a list of vagrants that have occurred in Colorado "but make no sense" is highly erroneous. The latter three species have a long-established pattern of occurring willy-nilly across the continent (in addition to concentrations in certain regions, such as Euro Wig in the Pacific NW and Little Gull on east coast/Great Lakes). Reddish Egret is a well known wanderer north of its normal range in spring, and especially in late summer/early fall. I would be rather surprised if Reddish Egret, Little Gull, or Euro Wig had NOT shown up in Colorado at some point. I would also be modestly surprised if Ross's Gull had not. The Sooty Tern occurrence, as shocking as it is superficially, was related to a hurricane/tropical storm (as I've been told) and is a species famous for being blown far afield by these storms. CO is a surprising place in that it is farther w. than the vast majority of these occurrences (or perhaps all), but I am not sure that the distance is greater, as there have been multiple storm waif Sooties in eastern Canada's interior. Finally, The Streak-backed Oriole is a mega-rarity, no doubt. But it hardly "makes no sense" in that the occurrence in CO is really just an extension of its somewhat regular northward vagrancy into the SW USA. These explanations take no wonder away from their occurrence. I still go WOW when I think of the Sooty Tern... but a goodly explanation exists. This discussion is likely winding down, and I am likely adding to the torture of it... but before one puts forth a litany of great birds that have been accepted in CO as evidence for the sparrow's natural origin, please consider the context of these records first. I am perhaps a bit more agnostic than Tony in saying the a Rufous-collared Sparrow is utterly impossible in CO. However, I would say that the probabilities, based on prior patterns, the species' natural history, etc. are very very low. The bird shouldn't be ignored. Its presence is of interest for reasons stated previously by Ted Floyd and me. However, making certain that the occurrence is documented and noted is a far cry from suggesting wild origin. Best Wishes to All Steven Mlodinow Longmont, CO -- You received this message because you are subscribed to the Google Groups "Colorado Birds" group. To post to this group, send email to cobirds@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.
