A male peregrine falcon perches on the Bank of America building in downtown Providence. Peregrines are the fastest animals on earth, capable of attacking prey in a dive at 200 mph. The birds can often be seen soaring nearby.

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The Providence Journal / Scott Kingsley

PROVIDENCE

Three peregrine falcons have hatched from their eggs in an aerie on the Bank of America building, and their parents are incubating two more eggs.

Joe Zbyrowski built the falcons’ nesting box on the 30th floor of the building in 1996. Last week, he watched the adult female leave the nest for about two minutes. She returned with a downy young pigeon that she had snatched from its nest and killed. She shredded it to feed to her nestlings.

Peregrines are the fastest animals on earth, capable of attacking prey in a dive, or “stoop,” at 200 mph. They hunt smaller birds.

Falcons are also nesting on the Pell Bridge and the Mount Hope Bridge, Zbyrowski said. The adult female nesting on the Pell Bridge was born in Boston, and the male was hatched in Providence, according to the bands on their legs.

The adult female, or “falcon-gentle,” on the Bank of America building arrived here as a one-year-old in March 2000 without a leg band. The male, or “tercel,” arrived in March 2004 wearing a band, but no one has been close enough to read it, Zbyrowski said. It is the second male to mate with the female falcon in the city. The first male died.

It’s unusual for a falcon to lay five eggs, Zbyrowski said. A female generally lays two eggs when she is young, four eggs at her prime and two eggs when she is older. Nestlings hatch in 28 days, he said. He speculated that the two remaining eggs in the nest may be infertile.

Zbyrowski and a representative of the U.S. Fish and Wildlife Service will band the Providence birds when they are about 19 days old.

The adult female falcon has seen 20 of her offspring fledged since she laid the nest’s first clutch of eggs in 2000, according to Zbyrowski’s records.

Retired from teaching in Coventry, Zbyrowski lives in North Stonington, Conn. Zbyrowski has studied raptors for more than 30 years and installed the nesting box back during a national campaign to bring the birds back after use of chemical insecticides had wiped out their numbers .

He commutes to Providence to track the peregrines’ progress. “They’re like babies,” he said. “They eat, and they poop and they grow.

“And they become aware of their environment. They become attuned to the voice of the parents. Then they’ll begin to visually look for the parents to bring food. Then they’ll start to notice each other and things in and around the nest box. They’ll start looking at insects in the box, and then they’ll start looking out of the box, taking in their environment.

“Eventually, they get closer and closer to the edge of the nest box. Then they’ll perch on the edge of the box. It’s situated so they can go out to a platform or a ledge where they’ll exercise: It’s jump and flap the wings, jump and flap the wings.

“They’ll do that until they gain the strength to fly off, and when they do, the first flight is usually a spiral-down flight. On the [Bank of America] building, they have the possibility of going down to a lower floor, rather than down to the street.

“They may move around there, flying short distances — five or six feet — until they gain more strength. Then, they’ll fly around the building from one level to the next. After that, they will go to the nearest building, and then they will fly farther and farther away, eventually learning to hunt.”

Initially, the adult birds bring prey to the nest box, and tear it apart for the nestlings.

“Eventually, they’ll bring back whole birds and leave them for the young to pick apart,” Zbyrowski said. “When the young falcons are out on the building, the adults will bring them food out there.

“Then the parents will encourage the young birds to come to them for the food.

“Then, when they’re all out flying, the parents will drop the food in mid-air, and the young ones will have to catch and retrieve it. The young ones do a lot of chasing without catching anything for quite a while until they finally get the hang of it.

“That’s the time when a lot of accidents happen. Glass is a big problem. They’ll fly into what looks like an open area in the sky. They’ll hit wires and buildings, and other things, too, but glass is a big issue.”

Once the birds become full-fledged hunters, Zbyrowski said, they will leave their parent’s hunting territory, never to return.

There is no public access to the falcons’ nest, but the birds can often be seen soaring over Kennedy Plaza.

tmeade@projo.com