The 16th annual Great Backyard Bird Count takes place Feb. 15-18, and it gets bigger and better every year. A joint project of the Cornell Lab of Ornithology, the National Audubon Society, and Bird Studies Canada, this popular citizen science project is an opportunity for all to discover the wonders of nature we call birds. And this year the GBBC is going global. Anyone from anywhere on Earth can participate by visiting www.birdcount.org. Begun in 1998, the GBBC enlists birders of all skill levels in an effort to keep common birds common. Last year GBBC citizen scientists turned in 104,285 checklists reporting a total of 623 species consisting of more than 17.4 million individual birds. "The GBBC is an ideal opportunity for young and old to connect with nature by discovering birds and to participate in a huge science project," said Gary Langham, Audubon's chief scientist. "This year, we hope people on seven continents, oceans, and islands will head out into their neighborhoods, rural areas, parks, and wilderness to further our understanding of birds across the hemispheres." The top five most frequently reported species last year were northern cardinal, mourning dove, dark-eyed junco, downy woodpecker and American crow. The most numerous birds nationwide were snow geese (3,259,470) and tree swallows (3,060,171). More than 3 million tree swallows roosted near Ruskin, Fla., during the count. (One local observer remarked about the swallows, "It's beyond description. There are so many birds that they look like little pixels on a computer screen.") Observations such as these demonstrate that the GBBC provides a valuable snapshot of where birds are in midwinter. Such data helps detect changes in birds' numbers and locations from year to year. This year I expect record counts for northern irruptive migrants. Reports of red-breasted nuthatches, pine siskins, evening grosbeaks, common redpolls, and red and white-winged crossbills have been widespread this winter. The GBBC also serves as an early warning system for worrisome declines in bird populations. Past GBBCs, for example, showed a drop in reports of American Crows since 2003, coincidentally with some of the first widespread outbreaks of West Nile virus in the U.S. This "signal" is consistent with data from more intensive Breeding Bird Surveys, as well as studies demonstrating declines of 50 percent to 75 percent in crow populations in some states after outbreaks of West Nile virus. Maps from the count also have recorded the dramatic range expansion of Eurasian collared-doves. Introduced to the Bahamas in the 1980, the collared-doves were reported in just eight states during the 1999 GBBC. By last year, collared-doves had colonized the Pacific Northwest, though they remain curiously absent from New England. Last year, New York ranked first (6,614) in the number of checklists submitted, followed by California (5,619), Pennsylvania (5,420), North Carolina (5,116) and Texas (4,577). States reporting the most species were California (333), Texas (327), Florida (280), Arizona (239) and Oregon (205). Anyone, from novice bird watchers to experts, can take part in the Great Backyard Bird Count. There's even a GBBC for kids. Participants count birds for as little as 15 minutes (or as long as they wish) on one or more days of the event and report their sightings online. It's easy, free, and fun. Results are updated hourly on animated maps and colorful graphs for all to view. This near-instant feedback allows participants to see almost immediately how their observations fit into the global perspective. Results from previous GBBCs also are available online. The lab also receives thousands of digital photos each year from all over the country. To see some of the best recent photos and the winners of GBBC photo contests, visit www.birdsource.org/gbbc/gallery. In addition to results, the GBBC website includes a variety of other useful birding information, such as vocabulary, photos, birdwatching and bird feeding tips and vocalizations. It's a valuable resource for all birders, especially students. The GBBC is a terrific way to contribute to a better understanding of birds. For information about the GBBC or the Lab of Ornithology, contact the lab at 159 Sapsucker Woods Road, Ithaca, NY 14850, www.birdcount.org, or call 800-843-2473. Send questions and comments to Dr. Scott Shalaway, 2222 Fish Ridge Road, Cameron, WV 26033 or email email@example.com.