Skip to main content

Great Backyard Bird Count Helps Birds and People

Jan 31, 2023 ● By Sheryl DeVore
Redpoll bird

Photo by Susan Szeszol

Simon Tolzman doesn’t get many rare birds in his yard near downtown Chicago, but each February, he counts what he sees there, which includes chickadees and cardinals and non-native house sparrows. He reports the species and numbers online to the Great Backyard Bird Count (GBBC). “When it comes to any bird data at all, it is really of equal importance,” says Tolzman. “The more we know about just how many birds are being seen, especially in urban areas, is increasingly important in a world where we’re losing so many birds.”

The bird count, which anyone can do either in their yard or a chosen spot, runs from February 17 to 20 this year. “It’s very simple,” says Becca Rodomsky-Bish, project leader for the GBBC. “You watch birds anywhere for 15 minutes on any or some or all of those days and tell us what you see and hear. Somebody who is brand-new to birds could sit at their window and tell us what they see.” Plus, a free bird app helps beginners identify birds by sight and sound.

“We know there will be some errors or misidentifications when birding, but our data analysis takes that into consideration, and the power of thousands of people submitting bird sightings outweighs this potential,” she notes. The minimum count time is for 15 minutes on one of the four days designated for the GBBC, giving even the youngest community scientists a chance to contribute. In February 2022, an estimated 384,631 counters from 192 counties reported 7,099, or roughly three-quarters, of the world’s known species, according to GBBC data.

Susan Szeszol photographed this rare Eurasian collared-dove in her Chicago yard during a recent Great Backyard Bird Count. Photo by Susan Szeszol.

The Cornell Lab and National Audubon Society launched the GBBC in 1998 in the United States as one of the first online community science projects to collect data on wild birds and record it online in real time. Anyone can see the data almost as soon as it’s entered. Birds Canada joined the project in 2009, and in 2013, it became a global project when the Cornell Lab launched eBird, an online database that provides birders, scientists and amateur naturalists with real-time data on abundance and distribution of bird species. eBird includes year-round sightings from birders. “The GBBC data was saved in a database and the database was growing. We knew the power of the data would be richer if we had it all go into the eBird database,” Rodomsky-Bish says.

“To see real-time data coming in annually showing the trends in how many birds are being seen on a year-to-year basis is incredible to watch as a birder, and also incredible to watch from a data analysis standpoint,” Tolzman says.

Every bird counts in the Great Backyard Bird Count, including the great black-backed gull, seen here in its winter plumage in Lake County, Illinois. Photo by Susan Szeszol.

“The GBBC has specific protocols, which is one of the reasons scientists use our data,” Rodomsky-Bish says. Most of the researchers that use eBird data, which includes GBBC data, are looking at longitudinal questions, climate change, regional changes, if birds are starting to migrate sooner and if they’re being seen earlier or later than normal. GBBC data is often a part of that. February is a good time for the GBBC. It’s right on the cusp of one of many birds’ annual migrations.

“The power of data increases over a longer period of time in multiple, consecutive years,” Rodomsky-Bish says. “For example, the annual Christmas Bird Count, held for more than 100 years, along with other community science projects, have revealed that numbers of birds are declining. Each year, dozens to hundreds of research papers are published based on eBird data. One of the reason birds are so powerful is because they’re everywhere. They alert us to environmental cues we should pay attention to. You don’t have to take a science course to contribute to a project like this. We’re all scientists. All of our observations matter, especially when we add them up.”

That is why reports from Tolzman and others on the number of house sparrows seen during the GBBC is important, she says. Native to Eurasia, the house sparrow was introduced in 1852 into North America and quickly invaded most of the North American continent except the Florida peninsula. The species is currently found throughout agricultural and urban landscapes of North America except the Yucatán peninsula. Researchers used eBird data to determine why. “We found that climate may represent an important driver in the North American invasion of house sparrows, probably delaying the Florida invasion and so far, preventing the Yucatán peninsula invasion,” the authors write. “Given the species’ plasticity and generalist life history traits, it is possible that the house sparrow may overcome present climatic restrictions and invade the Yucatán peninsula if proper management is not set in action.”

Susan Szeszol, left, and Marcia Suchy participate in the Great Backyard Bird Count in February 2022, in Winthrop Harbor. Photo courtesy of Susan Szeszol.

In addition to providing good data, the GBBC is just good fun. “It gets people outdoors in the coldest part of winter, and it can be done right in your own backyard,” Rodomsky-Bish says.

Chicago resident Susan Szeszol, who has been participating in the GBBC as well as Project Feeder Watch for more than a decade, agrees. “It’s a great way to get people outdoors,” she says. “One of my favorite GBBC group birding events is the IllinoisOrnithological Society’s Gull Frolic which takes place at Winthrop Harbor. In 2022, my friend Marcia Suchy and I enjoyed the birding camaraderie and incredible birds. We saw bald eagles, common goldeneyes, a white-winged scoter and a harlequin duck, along with several species of gulls.”

She also watches and counts birds in her yard for the GBBC and Project Feeder Watch. “In 2011, my very first Eurasian collared dove arrived in my yard. Each year, the number of doves increased until I had one of the largest and most consistent numbers of visiting Eurasian collared doves in Cook County. Through my recordkeeping and eBird reports, I’ve discovered that they tend to visit my yard less often from December through February, so it’s always exciting when one or two show up for the GBBC. Last winter was an amazing irruption for common redpolls. When they showed up in my yard on GBBC days, I was very happy.”

The northern cardinal is a common bird seen in the Chicago region during the Great Backyard Bird Count. U.S. Fish and Wildlife Service/Public Domain.

An irruption refers to the movement of bird species to other areas, generally outside of their normal range, when resources are scarce. “It could be that snow pack is intense, burying access to food, or that the amount of foods they need to eat, such as seeds and cones, is low one season,” Rodomsky-Bish says. “It’s fun to see surprise birds like redpolls, but it’s just as important to see and record the normal birds. We want them all.”

Sheryl DeVore has written six books on science, health and nature, as well as nature, health and environment stories for national and regional publications. Read more at