Dead bird patrol provides sobering lesson

Pittsburgh Post-Gazette

As dawn breaks over the city, the light reveals the dead and the stunned — warblers, creepers, ovenbirds and thrushes, a few each day — at the base of tall buildings.

Flying at night, hundreds of species of migrating birds are attracted to the city lights. Come morning, when they get active, feeding to fatten up for the next leg of their journey, they rise up from the city’s canyons and the unlucky ones slam into the deceptive reflections of a window.

On any given morning, Matt Webb or a member of his Bird Safe team of professionals and volunteers set out on dead bird patrols of 10 routes Downtown.

GPS notes the time and place of each bird photographed. The dead go into zip-lock bags, the live ones into cotton sacks with drawstring tops for delivery to the Humane Animal Rescue Wildlife Center in Verona.

Bird Safe is a program of the Carnegie Museum of Natural History, where Mr. Webb is the urban bird conservation coordinator.

The team’s data contribute to research being done at the museum’s Powdermill Avian Research Center in Rector, Westmoreland County. Powdermill tests the effectiveness of various treatments of window glass to give manufacturers guidelines on bird-safe design.

Downtown is the focus of the patrols because of its density. Two to four bird carcasses are found, on average, each day, Mr. Webb said.

One recent morning, he patrolled Gateway Center, Market Square and several blocks north and east.

Among the birds he found, all dead, were a Tennessee warbler, an ovenbird and a wood thrush. Ovenbirds outnumber 2-to-1 any other migratory species found Downtown, he said, “and I have no idea why. Cleveland and New York report that their No. 1 species found is a whitethroated sparrow.”

Bird advocates in many cities have embarked on efforts to reduce kill zones and reduce nighttime lighting. Dozens of cities have Lights Out programs in which building owners turn off lights in large, glass buildings at night. The Audubon Society has played a lead role in this effort.

Of the birds Mr. Webb found that day, the wood thrush in Gateway Center told a bleaker story. He crouched to pick it up and turned it over to expose its white belly feathers and dark splotches that resemble watermelon seeds covered by a translucent veil.

The wood thrush “is a species of concern,” he said. “It is an endangered species in Canada. This bird is an indicator of the health of interior forests, and its numbers are plummeting.”

Maintenance workers at several Downtown buildings report the birds they find to Mr. Webb. One recent morning, he handed his card to two custodians he had just met and explained Bird Safe’s mission.

He said he doesn’t want to single out particular buildings “because we eventually want to create relationships with [owners] to start talking about solutions.”

Property owners may not know birds are at risk, he said, or they may be becoming aware and interested in solving the problem.

John Wenzel, director of the Powdermill Nature Reserve, said the focus is on migratory birds, in spring and fall, because they are the out-of-towners, passing through, without the street smarts of local pigeons, doves and sparrows.

Bird Safe is reporting some surprising details about their finds, he said. One is that recessed windows appear to be more dangerous than those that are flush with a building’s cladding.

“We think it’s because the window is a little darker so the reflection is a little more perfect. But it could be the bird thinks it’s a hole, a passage. We don’t know why.”

He said there is no way to prevent bird kills in cities but that some limited solutions could have a big impact. Lowrise buildings and homes account for most collisions because the vegetation that tricks birds is usually within a few stories high.

“Because urban trees create part of the hazard and since urban trees are generally limited to 20 to 30 feet in height, that’s the risk factor you can reduce,” he said. “What if we can reduce the problem down to the first and second stories of a building?

That’s something significant, something we could do. We want to figure out that sweet spot.”