Study: Chicago region's protected lands offer critical habitat for various bird species

Remember when dead bugs would plaster your car's windshield and front bumper during summer road trips? I also recall swarms of flying pests around our porch lights, and a lot more fireflies flashing in the yard. More butterflies, too.

Insect populations are crashing, another sign of our troubled ecological times. Birds need those bugs, of course, which is one of many reasons why their populations are falling as well. Other downward drivers include climate change, habitat loss, pollution, invasive species, and building collisions.

The journal "Annual Review of Environment and Resources," published in May, reported that 48% of bird species worldwide are known or suspected to be experiencing population declines. Only 6% are showing gains, and 39% are stable.

We all remember the bombshell dropped by the journal "Science" in 2019: 3 billion birds lost in the last 50 years, translating to 30% fewer birds overall. It's noticeable, in the field and in our backyards.

Birds are struggling, no doubt, but not all of them, and not in all places. Some good news emerged in June courtesy of the Bird Conservation Network (BCN), a coalition of 21 conservation organizations serving the Chicago region.

"Breeding Bird Trends in the Chicago Region 1999-2020" documents that some local nesters, previously in decline, are stabilizing or growing in numbers. Bellwether species such as Henslow's sparrow (up 3.4% per year) and red-headed woodpecker (3.3%), for example, are gaining ground.

The BCN report, based on 22 years of bird survey data, updates the status of species that raise families in natural areas within six counties: Cook, Lake, McHenry, DuPage, Kane and Will. Analysis was based on 30,000 bird census surveys conducted by volunteer birders under the BCN Survey monitoring program.

The surveys occur in target habitats (grassland, shrub land, wetland and woodland) during June and early July, prime nesting season in northeastern Illinois.

Data collected for 104 species reveal that 56% are steady or increasing in the region vs. 37% for the rest of Illinois.

"People in Chicagoland tend to forget how unique it is that we have so many green spaces concentrated in the area," said Eric Secker, BCN president. "We found that a lot of birds in Chicago are doing better than the rest of the state and elsewhere in the nation because we have so much land being actively managed and restored."

The protected lands - about 220,000 acres of county forest preserves, municipal nature preserves and state parks - in northeastern Illinois are critical to the health of our nesting birds.

In addition, these nonagricultural landscapes provide vital stopover habitat for migrating birds on their way to breeding grounds farther north.

Effective habitat management is complex business, and not a perfect science. Practices aimed at helping one species may be detrimental to another. Everything is connected.

Further, we don't always know why the population of a given species is up, down or holding steady. Trends for some birds, especially secretive ones, are poorly known.

BCN's survey work helps set priorities by identifying the species most in need of assistance. Private and public land managers use the information to guide their conservation efforts.

Grassland birds are high priority, which makes the upbeat news about Henslow's sparrow - and dickcissel, up 5.5% per year - a cause for celebration. These species benefit from open landscapes like Springbrook Prairie Forest Preserve in Naperville.

For the nondescript Henslow's, whose population is declining nationally, it's no stretch to say that northeastern Illinois is a region of global importance. Only an estimated 410,000 remain in the world, according to BCN.

BCN's analysis, however, shows that populations of other grassland specialists are falling, with bobolink, grasshopper sparrow and savannah sparrow each down about 3%.

Birders in search of northern mockingbird and pileated woodpecker - uncommon species in these parts - are facing slightly better odds. Both species are trending up. In the case of mockers, geographic range expansion is a factor.

You can see all the data for yourself, organized by habitat, at bcnbirds.org. The trends are eye-opening, and BCN rightly expects them to be a catalyst for action.

"Birds can be good indicators of the overall quality of the habitat in general," said Secker. "It's important to remember there are lots of areas that continue to be developed and under threat."

• Jeff Reiter's column appears regularly in Neighbor. You can reach him via his blog, Words on Birds.

Local bird populations

Field survey data from 1999-2020 reveal good and bad news for this sampling of our region's nesting birds.

<b>Trending up:</b>Blue jay

Chimney swift

Common yellowthroat

Cooper's hawk

Dickcissel

Eastern towhee

Henslow's sparrow

Red-headed woodpecker

Ruby-throated hummingbird

Sandhill crane

<b>Trending down:</b>American crow

Black-crowned night heron

Bobolink

Eastern meadowlark

Grasshopper sparrow

Ovenbird

Savannah sparrow

Sedge wren

Upland sandpiper

Willow flycatcher

Source: Bird Conservation Network