Dave Weaver writes:
Hi Ken,
I went up to the Crest today and nobody has seen any Rosy Finches yet. My guess is that the thin snows so far in Colorado (and only a trace here) have allowed the birds to stay north longer than usual...
Dave Refer to the table above. On average, in the seven years when the feeders were put up in late October, the Rosies arrived on November 2nd. However, they showed up as early as October 27 and as late as November 19th. It would be interesting to see whether snow cover in Colorado has any long-term correlation with arrival dates.
Last year the birds crowded around the feeder at Sandia Crest as soon as they were put up on October 27, their earliest recorded arrival date. Yet, they were very late in arriving at the Kandahar Condominiums at Taos Ski Valley.
Did they simply overfly TSV? Last winter there was unusually early and heavy snow cover in the Southern Rockies. On October 22, 2009, a storm left 12 to 18 inches of snow across the mountains of southern Colorado and northern New Mexico.
There may be a correlation between heavy snowfall to the north and the huge influx of Coastal (Hepburn's) Gray-crowned Rosy-finches that occurred in early January, 2007. This race is uncommonly seen at Sandia Crest (0-5 seen at any time each year), though it does migrate more regularly into Colorado. After banding no Hepburn's CGRF's at all during the early part of the winter of 2006-2007, they suddenly appeared in good numbers on January 7, 2007. A total of 104 Hepburn's GCRF were banded by mid-February. Only 29 were banded the next winter, and since then they have dropped back to 0-8 newly banded annually.
Several severe blizzards struck the Rocky Mountains during late December, 2006 and early January, 2007. Around New Years Day, 2007, a blizzard in Colorado may have been one of worst in history, with thirty feet of snow in one storm. "People in the Lower Arkansas Valley said the blizzard that devastated much of Southeastern Colorado will go down as one of the worst snowstorms in the region’s history." (Accuweather)
Locked
