Creating habitats for the birds

Birds' numbers have plunged sharply over the last half-century.

Loss of habitat, damage from predators, and widespread use of aerial pesticides that kill their insect diet decimated the populations of common nighthawks and chimney swifts in New Jersey and across the birds' breeding range in the United States and Canada.

The numbers of both have dropped by about 2 percent a year since 1966, based on bird counts in designated tracts, according to the North American Breeding Bird Survey.

But efforts - planned in Camden County this fall and already underway in Essex and Warren Counties - promise to create new nesting areas that may become a model for reversing the decline.

New Jersey Audubon and Covanta, a company that produces energy from waste at 45 locations worldwide, have collaborated to create the new bird habitats.

"If they're using it, it should increase the numbers," said John Cecil, New Jersey Audubon's vice president for stewardship. "Our goal is to stabilize the populations."

Nine-by-nine-foot patches of natural-colored pea-stone gravel have been placed on the roofs of Covanta buildings in Newark and Oxford to provide a safe spot where the common nighthawk can nest, company officials said.

Another patch will be added in October to the roof of the company's six-story building in the 600 block of Morgan Street in South Camden, officials said.

The bird usually nests on the ground, where predators such as raccoons, possums, skunks, and feral cats often eat the eggs.

For the chimney swifts, chimneylike structures of wood also will be added at the three Covanta locations later this year. The faux chimneys will be built by an area Boy Scout troop and other community organizations.

"By utilizing wasted space on our rooftops, we can provide nesting habitat that will increase the survival for these birds," said Kenneth E. Armellino, Covanta's director of environmental science and community affairs.

"We look forward to the results of this project and hope it can be a model to be used across the region and the state," Armellino said.

The effort "is in line with our mission to protect the environment by reducing landfilling and encouraging a sustainable ecology," said James Regan, a Covanta spokesman.

"It's a simple thing," Regan said. "If we can help these animals, it's definitely something we want to do."

The company and New Jersey Audubon expect to see others copy their effort, officials said.

"The concept of creating breeding areas on rooftops for wildlife and 'green roofs' is important for the survival of species such as these, especially in a state like New Jersey where land use and habitat availability change so frequently," said John Parke, New Jersey Audubon's project stewardship director for the north region.

Nighthawks are medium-sized gray, black, and brown birds, known as "nightjars" because they jar the night with their calling. Their erratic flight is most often seen at dawn and dusk.

Chimney swifts are medium-sized, sooty-gray birds with long, slender wings and short legs. Bird enthusiasts call them "flying cigars" because they are the size of a stubby cigar.

Hundreds of common nighthawks - about 500 were estimated, based on two sampled 25-mile-long routes - and 40,000 chimney swifts - based on 27 sampled routes - are believed to remain in the state, according to the most recent survey, in 2013, by Partners in Flight, a nonprofit umbrella group for the conservation of land birds.

New Jersey Audubon said thousands of nighthawks would probably be found in the state if more surveys were conducted.

Across North America, there are about 16 million common nighthawks and 7.8 million chimney swifts, the Partners in Flight survey said.

The loss of flat gravel roofs in urban locations and of open woods in rural areas has reduced nesting areas for the nighthawks, which are also vulnerable to being hit by cars as they forage or roost on roadways at night.

At the same time, the chimney swifts, which used to nest in hollowed-out trees, shifted to chimneys in the 19th and 20th centuries, then found them closed off, said Cecil of New Jersey Audubon.

"The new chimneys have caps on them so animals can't get in anymore," Cecil said. "We have created chimneys at two of our offices and will be adding a third at another office.

"They're freestanding, about 16 to 20 feet tall, and are covered with vinyl," Cecil said. "We encourage people to build them."