Imagine a roost of robins containing more than 1.45 million birds - this confirmed in February at St. Petersburg, Fla., and you will no longer wonder where so many robins go in winter.
The super-massive concentration of these American favorites was just one of the surprising findings recently teased out of the reports from the 13th annual Great Backyard Bird Count (GBBC), which was held on a four-day weekend in mid-February.
During the event, more than 97,200 bird checklists were submitted by an estimated 63,000 volunteer bird-watchers from across the United States and Canada. The lists included 602 species and 11.2 million birds.
In terms of human participation - birders out there on the ground, observing and submitting reports - Mentor, Ohio, east of Cleveland, led the way with 709 checklists.
The GBBC is a joint project of the National Audubon Society and the Cornell Lab of Ornithology with Canadian partner Bird Studies Canada and with its reports of rare species to large-scale tracking of bird movements, the GBBC provides insight into the lives of bird populations
The results provide a snapshot of the whereabouts of the 600-plus species. "There's simply no better way to collect information about all these birds so quickly across such a large range," said Janis Dickinson, citizen science director at the Cornell Lab.
In addition to the super-roost of robins in St. Pete, observers recorded 400,321 additional robins across the entire rest of the continent. Reports such as these help document hot spots for robins and year-to-year changes in their movements across the continent.
At the other extreme, one of the most dramatic results from this year's count was the absence of other bird species, including winter finches such as pine siskins and redpolls. Siskins moved south in such great numbers in 2009 that they burst onto the GBBC top-10 list of most numerous birds for the first time.
Over time, the GBBC has captured dramatic swings in the numbers of these species reported from year to year. These fluctuations may be influenced by the birds' food supply and reproductive success far to the north. This year, siskins presumably didn't need to travel as far south to find enough food.
Results from this year's GBBC also documented the continuing expansion of an introduced species across the continent. A dozen years ago, the Eurasian collared-dove was reported in nine states during the GBBC. This year more than 14,000 doves were reported in 39 states and provinces. So, another invasive species makes a dent.
Tree swallows showed dramatic increases in numbers reported compared to years past. Although the number of states reporting the species was down from 25 in 2009 to 20 this year, the number of individuals reported increased nearly four-fold, from 22,431 to 84,585. Whether this is a result of warmer temperatures and earlier migration is not yet clear.
Notable sightings this year included a crimson-collared grosbeak in McAllen, Texas, - the first time the species has been reported during the count since 2005. Birders off the coast of San Diego were treated to a red-billed tropicbird - the first verified sighting of this species for the GBBC. Highlights from Canada included a rustic bunting seen in Creighton, Sask. In Marathon, Ont., a gray-crowned rosy-finch was a spectacular sighting because it was far outside its normal range in the Rocky Mountains.
The next Great Backyard Bird Count is Feb. 18 through 21. View the complete summary of the 2010 GBBC at birdcount.org and ebird.org.
The GBBC report comes just in time for birders to tune up for the first major wave of neotropical songbird migrations, which normally peaks in this latitude between April 25 and 30.
Two other major waves occurs, one around Mother's Day, and a third around Memorial Day.
Though many species, from waterfowl and shorebirds to robins and other commoners have moved in or through en masse already, what most tweaks the interest of dedicated birders are the arrivals of the neotropicals, especially the family of wood warblers. Those include nearly three dozen species of which annually may pass through the southwest Lake Erie region.
Magee Marsh State Wildlife Area, the adjoining Ottawa National Wildlife Refuge complex and the 10,000-foot boardwalk at Trautman Nature Center at Maumee Bay State Park are hubs of southwest lakeshore birding activity every spring. Magee and Ottawa lie along State Rt. 2 west of Davis-Besse in western Ottawa County, and the park is at the end of North Curtice Road off Route 2 in eastern Lucas County.
Expect the first big surge of migrants during next spell of warm windy weather with strong southwesterly flows, said Mark Shieldcastle, research director at the Oak Harbor-based Black Swamp Bird Observatory.
Until then, he said, observers can expect "one-ofs" among many species, including some which overfly their summer range, and eventually drift back south.
Current passages include the last of the golden-crowned kinglets and first of the ruby-crowned kinglets, fox and white-throated sparrows, and hermit thrushes.
The dominant bird in the first neotropical wave will be the male myrtle warblers, with black-throated green, Nashville, palm, and black-and-white warblers in sub-dominant roles, Shieldcastle said.
As part of spring migration observances, BSBO is helping organize what is billed as the inaugural Biggest Week in American Birding, set for May 6 through 16. Details are at bsbo.org.
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