Photo credit: Kevin J. McGowan

This year's GBBC showed Mountain Bluebirds were farther south than usual.

Nearly 50,000 checklists were submitted to the sixth annual Great Backyard Bird Count (GBBC), February 14–17, 2003. Participants observed 512 species and more than four million birds during the count, which is developed and maintained by the Lab and Audubon, and sponsored by Wild Birds Unlimited.

Highlights from the GBBC this year include once again the Sandhill Cranes, which followed their tight migration path from their Florida wintering grounds toward their breeding grounds in Michigan, Wisconsin, and parts west. Brewer's Blackbird is common throughout the West but breeds eastward to about the same localities as cranes in Michigan, Wisconsin, and western Ontario. Recently it has been wintering in increasing numbers in the Southeast and into Florida. This year's map of Brewer's Blackbirds in the Southeast shows a sharply defined eastern boundary that mirrors the migration path of the Sandhill Crane.

The Northeast suffered a severe winter this year, with a strong winter storm on the weekend of the count. Perhaps as a result, some species, such as Red-winged Blackbird, Eastern Meadowlark, American Woodcock, and Sandhill Crane, were found a bit farther south than in previous years. All of these species winter in the southern United States and are among the first spring migrants to return to the North. They track local conditions and typically push north as far as weather allows.

The storm affected local movements of birds as well. Dark-eyed Junco numbers at feeders went up through the count weekend across the Northeast. More people reported juncos as the stormy weekend progressed, and flocks got bigger and bigger too. In bad weather it's good to stick near the food.

Still, not all birds follow the same patterns. The GBBC maps of American Robin and Eastern Bluebird, also short-distance migrants, indicate that these species actually were farther north than usual. Perhaps a good berry crop in the North allowed these winter frugivores to stay north throughout the hard winter.

In the West, Mountain Bluebirds appeared to be farther south than usual and were almost entirely contained in the four southwest border states. In 2000, all the Mountain Bluebird reports were concentrated in the Four Corners area and east; this year almost none were there (see maps below). On the other hand, the rosy-finches seem to have stayed farther north this year. Few were reported in the more southwestern states where they had been seen in the last few years.

GBBC maps from 2000 (left) and 2003 (right) show striking contrasts in the distribution of Mountain Bluebirds during winter in different years.

Anyone who writes about recent bird distribution has to talk about the Eurasian Collared-Dove. Since its introduction into the Bahamas in the 1970s, this species has saturated Florida and moved rapidly northwestward. Previous GBBC maps have dramatically demonstrated its spread. But we may be seeing a slowdown or halt to this expansion. This year's map showed no significant change from last year's.

Where were the winter finches this year? Last year's GBBC maps nicely illustrated a huge winter finch invasion. These boreal-nesting birds show a roughly biennial cycle of irruption into lower states, and the winter of 2002–2003 was expected to be an off year. The GBBC maps show that it was. Crossbills were hard to come by pretty much anywhere this year.

The White-winged Crossbill was virtually absent from the United States, with only a cluster of reports in northern Wisconsin, Minnesota, and Michigan. Although Red Crossbills showed up in their usual pattern across the West, we received fewer than a handful of reports from the East. It's interesting to note that the single dot for Red Crossbill in northeastern Alabama has been there every year of the GBBC. This small breeding population has been present for the last four years and seems to be resident.

Although a few Common Redpolls were reported, the great concentration of sightings on last year's map around the United States–Canada border was missing. If you select the option on the web site to view a multi-year animation, the maps for this species in particular are fun to watch—the big cluster of pink, showing the highest densities of birds, blinks on and off every other year across southern Canada.

You can explore more results online by using our map room, search features for species and locations, Top-10 lists, tallies, and snow-depth summaries at www.birdsource.org/gbbc

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