Soaring above a large crowd gathered at the summit of Pack Monadnock on Saturday afternoon, a rehabilitated broad-winged hawk joined the thousands of other raptors that migrate past the mountain every fall.

Raptors are birds of prey sometimes referred to simply as hawks. They also include falcons, eagles, osprey, kites and harriers.

The hawk released Saturday was rehabilitated at Wings of the Dawn Bird Sanctuary in Henniker after it was found in a field injured and unable to fly. The bird was released from the Pack Monadnock Raptor Observatory in Miller State Park in Peterborough.

The observatory, which is staffed every day from Sept. 1-Oct. 1, is operated by the New Hampshire Audubon Society with the help of a large group of volunteers.

N.H. Audubon Society President Michael Bartlett said one of the main goals of the raptor release and the observatory is to teach the public about nature.

“One thing that the New Hampshire Audubon Society does really well is connecting people with wildlife and nature,” Bartlett said. “But this event sets the gold standard.”

While raptor releases are held only in the fall, visitors are invited to the observatory throughout the season to watch for and learn about the various species of migrating hawks that pass the mountain.

According to site coordinator Julie Tilden, this observatory is the best location in the state to see these migrating hawks, some of which travel from Canada as far as South America.

Hawks flying south for the winter tend to congregate along mountain ranges that run from north to south, as the ridges create updrafts of air that make the flight easier for the birds, Tilden said.

Every fall and spring, as the hawks migrate south and then back north, biologists and volunteers at the raptor observatory record the numbers and types of raptors that fly past the mountain in an attempt to track the birds’ populations.

Between 6,000 and 10,000 hawks, mainly broad-winged hawks like the one released Saturday, are counted every fall at the observatory. Data collected at the observatory is not only used by the state but is also entered into a national database administered by the Hawk Migration Association of North America, which is used to track raptor populations nationwide.

Tilden said studying the populations of hawks, and whether their numbers are increasing or declining, is important to protecting not only the birds, but also the state’s ecosystem in general.

“Raptors are the top predators of the food chain,” Tilden said. “So, if an ecosystem is healthy, they should be present. By learning about raptors in a certain landscape, we’ve learned a lot about the health of the ecosystem.”

While the population of broad-winged hawks in New Hampshire is stable, Bartlett said the populations of one-third of all breeding birds in the state are declining, making the research done at the raptor observatory important.

Tilden said if a species of bird is found to have a declining population, there are several ways to help promote population growth, including identifying and protecting nest sites and other bird habitats.

Tilden and Bartlett spoke about the importance of studying raptors to the large group of people, many of whom were equipped with binoculars, cameras and even large telescopes, gathered at the summit to watch the hawk be released Saturday.

After the crowd wished it safe travels, the bird was set free, swooping over its audience and disappearing around the other side of the mountain.

Many audience members stayed behind after the release, talking and watching for other hawks.

One such bird-watcher, Alan Bostick, of Groton, Mass., said that although he has been to a raptor release at the observatory before, he’s always impressed by the people who operate the site.

“The people from the Audubon have been great about teaching and helping to identify birds,” Bostick said. “It’s a great group of people. … Not being in the ecology or conservation career, it’s amazing to see so many young people so dedicated to what they are doing.”

Danielle Curtis can be reached at 594-5833 or dcurtis@nashuatelegraph.com.