Dozens of local birds, including the rare Henslow’s sparrow, are doing surprisingly well in Chicagoland, according to an analysis of 22 years of data by the nonprofit Bird Conservation Network.
Of 104 key species tracked in the study, 56% had populations that were stable or increasing, likely due to the Chicago region’s many parks and nature preserves, which cover nearly 10% of land in the six-county area.
In contrast, only 37% of the tracked birds are increasing or holding steady in other areas of the state, according to the North American Breeding Bird Survey.
“I think that’s a fun finding for people given that you think of Chicagoland as being more developed,” said Bird Conservation Network President Eric Secker. “Forest preserves, park district lands — in Chicagoland there’s quite a mix of organizations that are protecting land for birds, and we’re seeing those who are really helping them survive.”
In other parts of the state, he said, agriculture has often consumed prime bird habitat.
The study, which began in 1999, drew on more than 29,700 surveys conducted by volunteer monitors at almost 2,500 locations in area parks and nature preserves.
Among the birds that appear to be benefiting from living in the region: the 3- to 4-foot tall sandhill crane, the dashing red-headed woodpecker — with a crimson head and crisp patches of black and white — and the elusive Henslow’s sparrow, which is considered endangered in Canada and seven US states.
Only about 410,000 breeding Henslow’s sparrows remain in the world, and the birds are declining nationally. However, the conservation network study found the birds were up an average of 3.4% per year in Chicagoland.
Henslow’s sparrows often benefit from habitat restoration efforts and the creation of tallgrass prairie.
Sandhills were hunted almost out of existence in Illinois by 1900, and were listed as endangered in the state as recently as the 1990s. But they were found breeding in Lake County around 1980, and are now increasingly common, with suburban sightings popping up in social media posts.
Sandhills saw an average annual increase of 7.4% in the study. The authors cautioned that the increase may be due in part to the loss of wetlands in other parts of the state, with the birds flocking to the wetlands that remain.
Previously in steep decline, red-headed woodpeckers seem to be responding to practices such as the clearing of invasive species and restoration of open oak woodlands, according to the study, which found a 3.3% average annual increase.
Red-headed woodpeckers are declining in other areas of Illinois, perhaps because of the loss of oak woodlands, which offer food in the form of acorns, the study said.
The stunning northern flicker, with its neatly polka-dot underbelly and wings lined in bright yellow, is increasing slightly in Chicagoland but declining elsewhere in Illinois.
The study released on volunteer monitors — experienced birders who went out to parks and preserves to conduct counts according to detailed instructions. The monitors used eBird, an online database with a free app for recording and sharing sightings.
“One of the things that’s really exciting about this study is not just the results, but also the approach that was taken, really involving people in the community, and having them be part of the process,” said Chris Wood, director of eBird and managing director of the Center for Avian Population Studies at the Cornell Lab of Ornithology.
Not all of the news from the study was good. Species showing declines included the ovenbird, which relies on heavy leaf litter, and the beloved bobolink, known for its distinctive coloring and song, as well as its impressive annual migration. The black-and-white bird with a straw-colored head patch can fly up to 12,500 miles to and from South America in a single year.
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Bobolinks were down 2.9% annually, with Secker offering several possible explanations. A lot of restored grasslands in the area tend to be dominated by tall grasses, and bobolinks may prefer a mix of grasses and flowering plants. It is also possible that an international decline in insects, which is of concern to scientists, may be reducing the birds’ food supply.
Lastly, the problem may not be limited to this region — or even this country. Bobolinks are poisoned by farmers in Central and South America, where the birds feed on crops.
Still, the big takeaway is that Chicagoland’s investment in preserving and restoring natural areas is working well, Secker said.
Now he wants to use the information from the study to help local birds.
“We’re really trying to take the next steps to really collaborate more with land managers and make change happen,” he said. “Not just to present this data but to start asking the follow-up questions: the species is declining, what can we do about it?”
That might include creating a score card to help determine priority birds for parks and preserves, Secker said, or offering a map of the places where high-priority birds are found.