Peregrine falcon chicks hatch from downtown Boise nest

jsowell@idahostatesman.comMay 10, 2014 

Three Peregrine falcon chicks broke out of their shells between Monday and Wednesday in the nest box on a ledge of the 14th floor of the One Capital Center in downtown Boise.

A fourth egg isn't expected to hatch. The adult birds will eventually roll the egg out of the "scrape area" and off to the side of the nest box, according to The Peregrine Fund.

"The chicks are not yet capable of regulating their own body temperatures, so they will need their parents to keep them warm for about 10 days," The Peregrine Fund said.

The yolk inside the egg, which nourished the embryos during incubation, was absorbed into the body cavity of the chicks immediately prior to hatching, the group said.

Although the yolk keeps the chicks well-nourished for a few days, their begging instinct kicks in right away. The adults feed the chicks bits of food by tearing off small chunks of meat and delicately placing them in the chicks’ beaks.

The birds eat pigeons, mourning doves, starlings and other birds in Boise.

"From our experience of successfully raising thousands of falcons in captivity in the last 40 years, we know that a begging chick is not necessarily a hungry chick," according to the Peregrine Fund. "The adults know how much food each chick requires. As effective as The Peregrine Fund is at feeding chicks, we can’t do it as well as the natural parents."

Hatching is exhausting work for the chicks, who develop an egg tooth on the top of their beaks. The sharp tooth is used to pierce the inner membrane and the shell itself. The hole that is formed allows oxygen to pass into the egg and fill the chick's lungs.

There's even a name to the hatching process: pipping.

The bird parents know when a chick is about to emerge from the egg because it will start making noise. A large muscle on the back of the chick's neck allows it the strength to chip its way out of the egg.

It takes about 48 hours for hatching to begin after the pipping process begins. The chicks will punch a hole about the size of a dime in the shell and then use the eye tooth to cut the top off of the shell.

A few days later, the eye tooth falls off and the pipping muscle disappears.

The first egg was laid March 28, the earliest date since the webcam was installed in 2009. It was two weeks earlier than last year. Officials said wild birds keep their own schedules.

The Peregrine Fund was founded in 1970, during a time when Peregrine falcons were in danger of extinction in North America and in Europe. The falcons had disappeared from the eastern United States and were in serious decline in the the western half of the country.

The widespread use of DDT and other pesticides was blamed for the falcon's decline. Captive breeding began in 1971.

The Peregrine falcon was removed from the Endangered Species List in 1999.

Since 1984, The Peregrine Fund has been headquartered at the World Center for Birds of Prey, a 580-acre site outside Boise.

A live webcam can be viewed here. The camera has been operational since 2009.

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