North American Birds

VOLUME 69 NO2 2016

A Quarterly Journal of Ornithological Record Published by the American Birding Association. The mission of the journal is to provide a complete overview of the changing panorama of our continent’s birdlife.

Issue link: http://nab.aba.org/i/705084

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N O R T H A M E R I C A N B I R D S 200 T H E C H A N G I N G S E A S O N S : C A R B O N C O P Y ple Finches, probably because the human population in the East is larger and the habi- tats more accessible overall. With eBird, we begin to see more clearly the many vectors of movement involved in these irruptions: Cassin's Finches seem to be moving to lower elevations across enormous areas of the West, but by no means uniformly. In an average fall/winter, eBirders' checklists show frequency across the U.S. range of the species at about 0.2% of checklists. In fall 2014, this figure doubled to 0.4% from 1 September through 15 October and remained above average (about 0.3%) through the winter. This increase might not sound like much, but "on the ground," it meant welcome encounters with the species, both at feed- ers and in patches where one might not see many in several consecutive sea- sons. Dispersing birds even reached a few "new" areas for birders, such as the Yu- kon, which recorded its first Cassin's Finch ever at Cow- ley Creek 15 February. At singles made it east to Calgary and Beaver Crossing, Alberta and Saskatoon, Saskatche- wan. In the central Rockies, Tony Leukering and Matt Fraker descirbe a "relatively mas- sive downslope flight" into the eastern foot- hill counties of Colorado, with a few straying well onto the eastern plains of that state. To the east, elevated numbers of Cassin's were detected into the western Plains in Kansas, Nebraska, Oklahoma, and northwestern Texas. The Texas Trans-Pecos also recorded numbers much above average, as did central and southern Arizona (where termed an "in- vasion"), but New Mexico counts were called "moderate" and came mostly from montane areas. Across much of the Pacific Northwest, however, numbers of Cassin's Finches were not much out of the ordinary, so presumably in some areas, food resources were adequate, the breeding season unremarkable, or both. Among and in addition to the Cassin's Finches, birders in the West hope for Purple Finches and now distinguish Purple Finches of the nominate subspecies (Eastern Purple Finch) from those of subspecies californicus, found mostly in Pacific ranges from British Columbia to California. Digital photogra- phy, and distribution of images via internet, has permitted a quantum leap in the iden- Atlin, British Columbia, a first-local-record Cassin's was joined by three Purple Finches, nearly as rare there (Figure 2). Two Cassin's turned up on the southern California desert at Jacumba, where very uncommon, in late February. In the Prairie Provinces, vagrant Figure 2. During a major irruption season for Cassin's Finch across the West, this bird established a first record for extreme northwestern British Columbia at Atlin 2 February 2015. Photograph by Cameron Eckert. Figure 3. Utah's second record of Purple Finch, and first photographic record, was found at Lytle Ranch Preserve, Washington County 7-24 (here 15) January 2015. Photograph by Rick Fridell.

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