By Rob Fergus, Senior Scientist, National Audubon Society

	Kilohana Scout Troop. Amara Milner Nguyen, HI, 2008 GBBC

In 2008, the Great Backyard Bird Count (GBBC) reached new heights. For the fourth year in a row, participants sent us record numbers of checklists. As of March 24, bird watchers submitted 85,725 checklists with observations of 635 species, representing 9,805,216 individual bird sightings during the four-day count.

The GBBC provides an invaluable real-time snapshot of bird distribution across North America. Each year we see changes in where the birds are located, based on factors that include climate change, weather patterns, food supplies, diseases, and breeding success. With all of the data online, anyone with an interest in birds may explore what could be the first indicators of real trends and changes in bird numbers and distribution. In-depth studies are necessary to confirm the GBBC trends and to further test the reasons for the changes we see.

Readying the bird buffet. Photo by Susan Spear, NY, 2008 GBBC

In past years, GBBC results have shown annual differences in migrations of some species such as Sandhill Cranes and Tree Swallows based on mild or harsh weather patterns.  Each year the GBBC also shows the extent of southern incursions of northern owls and finches like crossbills, redpolls, and grosbeaks based on regular fluctuations in voles and other owl prey species or seed crops in the boreal forests. Range expansions of Eurasian Collared-Doves and Red-bellied Woodpeckers also show up each year during the GBBC, as do the ups and downs of species hit by diseases like West Nile virus. The 2008 GBBC results continue to shed light on these changes, and reveal trends in other bird populations as well.

New Species for the GBBC

Each year, if we’re lucky, GBBC participants report some species never seen before during the count. Often these are rare birds from other parts of the world, but sometimes they are just secretive or scarce birds that are few in number or difficult to find. This year, GBBC participants reported 12 new species for the count: Masked Ducks in Texas, Arctic Loon in California, Scarlet Ibis in Florida, Northern Jacana in Arizona, Black-tailed Gull in Rhode Island, Ivory Gull in South Dakota, Great Skua on the ocean off North Carolina, Yellow-naped Parrot in Florida, Olive-sided Flycatcher in California, Fork-tailed Flycatcher in Louisiana, and Akohekohe and Chestnut Munia in Hawaii.  Each of these sightings represents a thrill for the observer, as well as a valuable bit of information on the movements of these bird.

Common Species in Decline

This past year Audubon produced a report on common birds that are declining across their range (http://stateofthebirds.audubon.org/cbid/). The report was based on declines in bird numbers seen on the Christmas Bird Count and the Breeding Bird Survey. According to the report, Northern Bobwhite have declined by 82 percent over the past 40 years.  Northern Pintail are down 77%, Greater Scaup are down 75%, and Eastern Meadowlarks are down 72% over the same time frame.

We see many of these same declines in the GBBC data. In 2008, participants reported only 1,060 Northern Bobwhite on 218 checklists (4.64 birds per report), down from 1,012 birds on only 130 checklists (7.78 birds per report) in 2004. Over the past five years, Eastern Meadowlark reports from the GBBC are down from an average 8.6 birds per report to 7.5 per report. Reports of Northern Pintail and Greater Scaup went up over the same time frame. Reports from two consecutive years don’t always reveal a trend, but the longer we do the GBBC, the better our chances of spotting significant long-term changes in the numbers of these birds.

Alien Exotic Species

Broad-billed Hummingbird. Photo by Lynne Marsho, AZ, 2008 GBBC

The primary goal of the GBBC is to document native birds, but we also encourage participants to report sightings of alien exotic birds they may encounter. Some of these are escaped pets that will not make a lasting impact on local environments, but others may be breeding and becoming firmly established.

This year, the GBBC recorded sightings of at least 21 species not on the official North American bird lists—but they may be added if they continue to flourish in the wild. These include Peach-faced Lovebirds, with 174 individuals reported from 7 communities in the Greater Phoenix area, and the 275 Black-hooded Parakeets reported in a dozen locations in Florida. In 2001, the GBBC received its first report of a single Purple Swamphen, a Eurasian relative of the coot now found in Florida. As an indication of how these birds may be colonizing marshes in that area, this year the GBBC received a record high of eight checklists listing a total of 54 of these birds. The GBBC can help us keep track of these birds so we can spot and avoid potential conflicts between our native species and these new additions to our bird communities. In coming years, we hope to do a better job of tracking these and other exotics, including the nearly unstudied population of Red-vented Bulbuls in Houston, Texas.

Early Migrating Species

Because the GBBC takes place in mid-February, it shows us where most birds have been able to survive the winter. However, some birds are already beginning their spring migration during the GBBC, which provides a window on how these early migrants are doing from year to year.

As usual, this year the GBBC found Sandhill Cranes migrating up the Pacific Coast as far north as southern British Columbia, through the Great Plains with a few as far north as Nebraska, and a chain of birds moving from Florida up to Illinois and Michigan. Other rather typical results include Purple Martins as far north as Tennessee and North Carolina, and Tree Swallows in 22 states, with the highest concentrations in Florida and California, and the northernmost birds found in temperate British Columbia.

Northern Owls and Finches

2008 was a poor year for northern owl sightings across most of southern Canada and the northern United States. Only 10 Great Gray Owls were reported this year, a far cry from the 672 reported in the banner invasion year of 2005. Snowy Owls were found in nine states, indicating average southbound movements for that arctic bird, with most reports coming in from farther north in Manitoba and Quebec.

House Finch. Photo by Maria Corcacas, NY, 2008 GBBC

Birders alerted earlier in the winter to a massive seed production failure of trees across northern Canada, were prepared for a huge southern flight of northern finches. True to the prediction, the GBBC shows record high numbers for Pine Grosbeaks, with 15,830 birds reported from 31 states and provinces, with highest numbers reported from Quebec, Ontario, and Manitoba, and much higher than average numbers in many states including Maine and New York. Because of annual fluctuations in seed crops, even-numbered years are traditionally better for finding Common Redpolls and other finches and grosbeaks south of Canada, and 2008 proved to be one of the best flights of these birds in the past decade, with 100,805 Common Redpolls reported on the count, including checklists from 29 of the lower 48 States. Evening Grosbeaks, declining for years in the eastern United States, had their best showing since 2000, with 14,472 birds reported from 43 states and provinces.

Continuing Range Expansions

Each year the GBBC charts the explosive expansion of Eurasian Collared-Doves across North America. This year the count recorded a record high of 10,542 birds in 39 states and provinces, up from 8,080 birds reported from 35 states and provinces last year, including the first GBBC records of this bird from British Columbia, Manitoba, and Oregon. Remarkably, only 1,078 of these doves were found in eight southeastern states during the 1999 GBBC.

Each year we anxiously anticipate reports of Red-bellied Woodpeckers, to see if they are continuing to expand their range in the Great Plains and in New England. This year we had a record 23 reports of these birds from 11 locations in South Dakota. In Maine, however, there was a huge drop in reports this year, with only three woodpeckers reported from two locations, down from 13 reports from 9 locations last year, and a record 39 reports from 18 sites in 2005. Perhaps the record-setting snowfalls there this year have taken their toll on these colonizers from the south. Bird populations fluctuate from year to year, so once again we’ll be watching these numbers in Maine again next year!

Attack of the Killer Mosquitoes

Turkey Vultures. Photo by Tyler Tretten, CO, 2008 GBBC

We know that crows, jays, and their relatives are hit especially hard when West Nile virus reaches a new area, so for the past few years we’ve been watching the population of Yellow-billed Magpies decline as the virus has spread to California. This year magpie numbers there were down again to a new low of 6.6 birds per report, as compared to 23.7 per report in 2004 before West Nile Virus arrived in the area. Nationwide, American Crow and Blue Jay numbers appear to have stabilized a bit but bear continued monitoring as the populations of these birds continue to adapt to the presence of this new disease.

One Person Can Make a Difference 

Since the GBBC is still growing in participants, sometimes the changes we see from year to year are based on who shows up to count and where they choose to count each year. Last year we had six checklists reporting 64,423 Ring-billed Gulls from Corpus Christi, Texas. This year, we received only three checklists reporting 53 of these gulls from that location. Rather than indicating fewer gulls on the Central Texas coast, this probably shows that nobody counted birds from the landfill there this year. This missed count is enough to explain over half of the difference between the 2007 count-wide total of 300,601 Ring-billed Gulls and the 195,703 reported this year.

Do Some Exploring on Your Own

Explore the GBBC data on your own by visiting our map room and comparing counts over the years for a particular species you may be interested in, or for specific parts of the continent. You can call up your own reports by using the new “My Observations” feature.

Thank you for taking part in the 2008 Great Backyard Bird Count! The dates for next year’s event are February 13-16, 2009. We’ll see you then!