By Dick Cannings, Marshall Iliff, Geoff LeBaron, and Zach Slavin
The first international GBBC
In the first-ever global Great Backyard Bird Count (GBBC) this year, participants set all kinds of new records. During the count on February 15-18, 2013, participants reported birds from all 7 continents, including 111 countries and independent territories. Bird watchers reported 4,004 species from about 180 bird families–39% of the world’s bird species and 78% of bird families. (Species total differs from the number on the GBBC home page because that page is no longer being updated.) It is truly remarkable that participants recorded such a high percentage of the world’s avian biodiversity within four days.
To see the number of checklists submitted from each country, click here. Participation continued to soar in the United States and Canada, where the Great Backyard Bird Count has been conducted since 1998. See the list of checklists submitted from each state and province in the U.S. and Canada here. Many countries new to the count also made impressive contributions, including India, Mexico, Costa Rica, Australia, Peru, the United Kingdom, and others.
We hope GBBC participants will unite again next year to see how many of the world’s 10,240 species can be found!
Of the 4,004 species reported, Mexico tops the list with 645 species, followed by the United States with 638 (reflecting the high level of participation). India follows with 544 species, then Costa Rica with 508.
Panama, Australia, and Peru all tallied well over 300 species. Ecuador, Belize, and Kenya were among the countries reporting more than 200 species. Spain tops European countries in species diversity with 179.
The potential for a big species total is greatest in South America, home to nearly 1,800 species (compared with about 900 in North America). During the GBBC, Colombian participants reported 424 species. We expect those tallies to grow with increased participation.
Top reported species
Given the strong participation in the United States and Canada, the birds reported on the most checklists were North American:
No. of Checklists
Outside the United States and Canada, the top species tended to be those that are widespread in India, where participation was also high, or those that are abundant elsewhere in the world: Eurasian Blackbird (216 lists), a common backyard bird in India and Europe, followed by Black Kite and Great Tit, both of which are also widespread in Eurasia. The other most widespread species globally were House Crow, Black Drongo, Eurasian Coot, Eurasian Blue Tit, White-throated Kingfisher, Indian Pond-Heron, and Gray Heron. Another 2,405 species that were not seen in the United States and Canada were recorded at least once.
Most numerous birds
The largest flock during the GBBC was reported from Mark Youngdahl Urban Conservation Area in St. Joseph, Missouri. Observers there estimated there were 5 million Red-winged Blackbirds along with a flock of 1.5 million American Robins. Brent Galliart says, “The trees in the surrounding area were leaved in black (as opposed to green in the spring) with Red-winged Blackbirds.” This amazing report confirms the Red-winged Blackbird as one of the most abundant bird species in North America.
The second-largest flock was also reported from Missouri, 50 miles farther north at Squaw Creek National Wildlife Refuge. Multiple observers reported between 700,000 and 1.1 million Snow Geese.
The largest flocks reported outside of the United States and Canada were 50,000 flamingos in Lake Manyara National Park in Tanzania, and 45,000 Black-tailed Godwits at Estuário do Tejo outside of Lisbon, Portugal.
Widespread winter finches
The irruption of winter finches during the past winter has been dubbed a “superflight” by experts who study finch invasions. A variety of nomadic finch species has been moving farther from their usual winter ranges, most likely to find food when northern pine cone and seed crops fail.
Common Redpolls were on the move, with widespread reports from across southern Canada and the northern tier of the United States. Although there was less of a push into the northwest than we saw last season, their southward movement was more uniform, west to east, than the irruption into the Northeast in 2011. Redpolls were also reported in Iceland and northern Europe, where they occur regularly. Surprising numbers of Hoary Redpolls were reported as well.
Evening Grosbeaks made a good showing in the 2013 GBBC. While still not present in anywhere near the numbers they were 20 or 30 winters ago, these impressive seed gobblers were found along the Pacific Coast into the southern Rockies, and down into the Mid-Atlantic region during the GBBC.
Crowds of crossbills
With their unusual crossed bill-tip, used to extract seeds from conifers, sighting a Red Crossbill or White-winged Crossbill is always exciting for birders. Although both species are widespread (White-winged is more restricted to northern areas), both are highly nomadic and unpredictable. Some areas may not have any crossbills for years, only to have dozens or hundreds arrive in a given winter.
Red Crossbills occur patchily across much of the northern United States and southern Canada. When Red Crossbills invade, they can show up anywhere, though they tend to favor more northerly, mountainous regions where conifers are common.
In 2013, GBBC participants found Red Crossbills in a whopping 36 U.S. states and 9 Canadian provinces–far more than had even been found in past counts. Particularly notable were the large numbers found in eastern Wisconsin and the coastal mid-Atlantic, both areas where bird watchers sometimes don’t see this species at all.
Whereas most Red Crossbills feed on pines, White-winged Crossbills have smaller bills adapted to smaller cones, such as spruce, firs, and hemlocks. Their core range is across the boreal forest of Canada, just barely reaching into the northern tier of the United States. When White-winged Crossbills invade, they rarely penetrate to the southernmost states, but sometimes they can move in very large numbers and strays have reached Georgia, Texas, and California. They were expected in all Canadian provinces, but a remarkable 20 U.S. states reported the species this year. Most notable were the large numbers in Maryland, Pennsylvania, and New Jersey, and southerly sightings in Arkansas, Kansas, and Kentucky.
As a final wrinkle that makes crossbills even more exciting, we have learned over the past few decades there are at least 10 types of North American Red Crossbills, each with different calls and its own ecological niche. The possibility that some of these represent distinct species remains a topic of research. The possibility of audio-recording crossbills to learn more about where and when different types move is the very frontier of field ornithology today. eBird maps (including GBBC data) can be made for all 10 call types, from the widespread Type 2 and Type 3, to the highly restricted Type 9 (South Hills Crossbill). This is only part of the story, because Red Crossbills also live in Europe, North Africa, and Asia!
Participation from thousands of bird watchers worldwide is critical to truly learn the complexities of crossbill movements and how they change from year to year. To understand crossbills and other birds, we need not only data on where they occur, but also information on where they are not being found.
This year’s GBBC data show a strong echo of last year’s impressive flight of Snowy Owls. Snowy Owls appeared on 361 checklists. That’s an increase from last year’s 242, but the overall number of birds reported dropped from 635 to 553. (Because the same individual owls were recorded on multiple checklists, the actual number of Snowy Owls seen during this year’s count was about 192.)
This year’s flight was concentrated in the Northwest, with most birds reported in British Columbia (26), Alberta (30) and Saskatchewan (27); moderate numbers were reported from Washington (18), Wisconsin (18), Michigan (15), and Ontario (18). The Snowy Owl found farthest from its arctic home was one that delighted birders reported by birders on 31 checklists from Tybee Island at the mouth of the Savannah River in Georgia. This Snowy Owl was more than 700 miles from the next-most southern Snowy Owl reported at JFK International Airport just outside of New York City.
Bohemian Waxwings by Joan Tisdale, Michigan, 2013 GBBC
Whither wandered waxwings?
The plot for the Cedar Waxwing story this year is characterized by where these elegant birds were not found. Though a common species, it was tallied in surprisingly low numbers in the northeast quadrant of North America during the GBBC. Most likely there was not enough winter fruit crop to sustain birds in the region, and a much greater proportion of the species’ population retreated to its core winter range along the central Gulf Coast, where they were present both this season and last in great numbers during the GBBC.
Bohemian Waxwings were recorded in average numbers, with scattered reports in the eastern provinces of Canada and northeastern states, with fair numbers in the interior western provinces and Rocky Mountains.
Red-breasted Nuthatches on the fly
This winter was a big one for Red-breasted Nuthatches moving southward. Beginning in the fall, the woods were alive with the nasal “yeenk” of the nuthatches in southern New England and the mid-Atlantic states. By late winter, GBBC participants were entertained by them in the East, southward to the Gulf Coast and northern Florida, with scattered reports throughout the Great Plains as well. During winters like this one, when food supplies are scarce, this species may move southward in large numbers—classic irruptive behavior.
Take a look at the map below, where Red-breasted Nuthatches were reported in February 2012. As you can see, last winter a greater number of Red-breasted Nuthatches remained on their breeding grounds, with only widely scattered reports of sightings farther south.
Winter ranges shift for swallows
The signs of a warming climate are showing up in GBBC data, especially when it comes to insect-eating birds, such as swallows, that are now reported spending the winter months farther north than in the past.
The Northern Rough-winged Swallow has been one of the impressive examples, since it typically spends its winters in Mexico and Central America, but in recent years has established overwintering populations in areas where they were never seen before. Some of these sites are sewage plants where warm wastewater attracts flying insects that—in combination with warmer winters—have allowed these swallows to survive through the winter.
During this year’s GBBC, John Duke recorded seven Northern Rough-winged Swallows at Clayton County Water Authority’s E. L. Huie Ponds near Atlanta, Georgia. Northern Rough-winged Swallows had been reported here consistently since December. This is part of a larger pattern of Northern Rough-winged Swallows overwintering in East Coast states, with recent successful overwintering in New Haven, Connecticut, and Philadelphia, Pennsylvania. The site in Philadelphia hosted 17 birds reported to the GBBC on February 17.
Cave Swallow is a species that has greatly expanded its breeding range, taking advantage of bridges and culverts in addition to natural limestone caves. It has also expanded its winter range, now wintering widely in parts of Texas where it previously did not occur at all. In recent Novembers, groups of Cave Swallows have been swept up regularly in southwesterly winds and appeared as far north as the Great Lakes shorelines and the Atlantic Coast. As evidence that further expansion is possible, a few strays from the November 2012 invasion joined 30+ Northern Rough-winged Swallows wintering at a sewage plant in Philadelphia and at least one Cave Swallow stayed there until February 3, 2013. The swallows stayed there until late February, based on eBird reports.
Barn Swallows have been appearing more often during February on the West Coast, where Bank Swallows have also lingered later into the fall, and in recent years Purple Martins have even been found in boxes in midwinter. GBBC participants are helping to document this emerging phenomenon. The next 10 years of data will paint an interesting picture—perhaps one showing more and more swallows overwintering well north of middle America.
Perhaps one of the most unusual avian events of the winter of 2012-13 was a tremendous movement of Razorbills far south of their normal range. Razorbills are relatives of puffins. They breed on cliffs along both the North American and European sides of the North Atlantic. Their normal distribution in the nonbreeding season is at sea off the coasts of Europe, Iceland, Greenland, and the Atlantic Provinces and northeastern United States. Their exact wintering areas vary from year to year, depending upon the distributions of the ocean food resources upon which they feed.
Razorbills rarely wander farther south than Cape Hatteras, North Carolina. Prior to this winter there were only 14 records of Razorbill for Florida, mostly of single birds. Earlier this winter, hundreds of Razorbills were seen off the Atlantic Coast of Florida. The numbers have since dwindled, but GBBC participants documented birds that had rounded the southern tip of Florida and they tallied others in the Gulf of Mexico.
Why did Razorbills move so far from their normal range this winter? As with the winter finch and boreal raptor irruptions it probably had to do with a drop in food resources. Sea-surface temperatures were unusually warm off the mid-Atlantic region this winter, and that change may have greatly reduced the availability of prey, causing Razorbills to move farther southward in larger numbers than ever recorded before.
The winter of the lapwing
Hurricane Sandy slammed coastal communities in New Jersey and New York when the storm turned west to make landfall. The cause for this unusual movement (most hurricanes continue to the north and east) also produced “the winter of the lapwing” on the East Coast.
A system of high pressure over Greenland, known as a “Greenland Block” or “Rex Block,” caused Sandy’s unusual westward turn, and it also set up strong easterly winds blowing across the North Atlantic. On the day that Sandy made landfall, bird watchers in eastern Massachusetts noticed the first unexpected avian visitors from this system: a Northern Lapwing flew past First Encounter Beach on Cape Cod and two more appeared in an open field on Nantucket Island. More than a dozen would follow in the next two weeks. (Read more on their arrival.) Over the course of the winter, lapwings were discovered in 13 states and provinces.
GBBC participants have never recorded this species in North America, but this year 7 Northern Lapwings were found in 3 states, reported by 55 participants. The two birds that appeared on Nantucket on October 30 were still present and counted for the GBBC, along with three birds in New Jersey that were first spotted together in November. Georgia’s first-ever record of the species came February 6, and dozens of birders went out to see it during the GBBC weekend!
As of this writing, three lapwings continue to linger in New Jersey and a third one has joined the two on Nantucket. If each flock contains at least one bird of each sex, could the first North American breeding attempts occur next month? Could Northern Lapwings colonize North America, as the Cattle Egret and Lesser Black-backed Gull have during the last century? With the army of birders reporting to eBird and the GBBC, the next colonization of a European species could be thoroughly documented from the day of its arrival to the first nesting!
Thanks to all who participated in the 2013 GBBC for your valuable observations! Please continue to record your checklists year-round at www.ebird.org.