Thursday, August 6, 2009

Anatomy of a Rescue

Juvenile Peregrine Falcon (Falco peregrinus). Photo by Doug Brown

The Peregrine Falcon, a highly visible and charismatic species, was proverbial “Canary in a Coal Mine” that alerted us to the dangers of pesticides. Its precipitous decline, discovered in the 1960s, lead to worldwide concern among ornithologists, researchers, and falconers, who convened conferences to assess the situation and implement plans to prevent the falcon from disappearing altogether. Efforts to breed and release falcons began in late 1960s by several different organizations, including the Peregrine Fund, which was founded at Cornell University in 1970 and lead by ornithology professor, Tom Cade.

The P Fund, as it is often referred to now, began breeding falcons in captivity for release to the wild in an attempt to prevent further declines. They successfully bred and released more than 4,000 falcons from 1974 to 1998, resulting in a minimum of 700 re-established breeding territories in North America. The non-profit organization is currently based at the World Center for Birds of Prey in Boise, Idaho.

Peregrines, like other falcons, do not build nests but use naturally occurring cavities (scrapes) on cliff edges, often near water, where the female (referred to as ‘falcon’) lays her eggs on sand or gravel. Generally, these nest sites, called eyries, have an expansive view of the surrounding habitat from which the female can watch for intruders and the male (tiercel) can scan for prey. Peregrines prey almost entirely on birds in New Mexico, including doves, swifts, flickers, jays, meadowlarks, and others. At one eyrie, the remains of 62 bird species were identified. I’ve also watched them hunt for bats emerging from a cave at dusk, and research shows that they are opportunistic, taking other animals on occasion. They can take birds up to the size of ducks and pheasants, hence the nickname, Duck Hawk.

It’s the unique hunting style of the peregrine that has earned the admiration and adoration of countless numbers of falcon fanatics worldwide for, indeed, this falcon has circumpolar distribution, except for Antarctica. The falcon climbs high into the sky, watching for aerial prey below with eyesight that is 8-10 times the distance and acuity of the human eye. Once prey is sighted, the bird tucks its body into the celebrated stoop at speeds of 200 miles per hour or more, and dives on often unsuspecting prey. At the last moment, the falcon swings her balled feet forward and strikes the victim, knocking it unconscious. The falcon then swoops to pick up the prey, and using her tomial tooth (an extra notch on the underside of the upper bill unique to falcons), breaks the prey’s neck. The falcon then descends to the ground with the prey to eat.

Because the peregrine had been extirpated (absent) east of the Mississippi River, but was still present in the West, initial reintroduction efforts focused on this region. Early release sites were located on bridges over rivers that simulated natural falcon habitat and also allowed easy human access, often near major metropolitan areas. The birds took well to these releases and a small population began to thrive. However, although humans thought that the bridges might be an ideal habitat, the peregrines had other ideas about preferred nesting sites. The falcons began to move into cities where they nested on ledges of skyscrapers, and dined on the ubiquitous urban avifauna, notably the Rock Pigeon. It seemed that, in the falcon’s eyes, the city had everything that they needed: suitable eyries and an unlimited food supply.

An additional benefit accrued to the peregrines that took up residence in urban centers, an adoring public. As people became aware of the plight of the peregrine and began to notice the rare falcons nesting outside their high rise, high rent offices, they became falcon watchers and peregrine protectors.

Today, the everyday activities of countless pairs of urban nesting peregrines are chronicled via webcams and falcon watches on the web and in local newspapers. My web search for peregrine falcon news results turned up 119 stories less than 30 days old. This includes last week’s exploits of “Early Bird” a 37-day-old peregrine falcon that leapt from his eyrie on the 12th floor of the Joseph Smith Memorial Building in Salt Lake City. Although the first flight went well, the second did not. He crashed into a flower bed and returned to his nest box by volunteers who keep an eye on the falcons. The volunteers, known as the Peregrine Falcon Watchpost Team, will be on hand from dawn to dusk for roughly the next 10 days in case "Early Bird" or his sibling decides to try again.

Closer to home, peregrines have been observed in downtown Albuquerque although no nesting has been known to occur. Certainly, the falcons are finding ideal hunting conditions in our southwestern city, complete with an abundant pigeon population. One falcon watcher called to excitedly share the intimate details of the recent kill outside her high rise office window.
Not all peregrines have migrated to urban centers, and New Mexico still has a population that eschews city life for the solitude of wilder country. However, getting to see one in the back country is uncommon, even in the appropriate habitat. They remain a state listed threatened species by the New Mexico Department of Game and Fish.
The plight of the peregrine was the impetus for increased research, monitoring and conservation of all bird species. After their success in reintroducing peregrines, the P Fund pioneered propagation and release techniques for numerous species worldwide. Other species released to restore wild populations include the Aplomado Falcon, Bald Eagle, Bat Falcon, California Condor, Harpy Eagle, Madagascar Fish Eagle, Mauritius Kestrel, Orange-breasted Falcon, and Prairie Falcon. However, bringing a species back from the brink of extinction is the least desirable and most expensive way to save a species. The annual costs for recovery of the Peregrine Falcon were placed at more than $5.4 million in the 1990s. Thus, the shared goal of “keeping common species common” is the mantra that drives most conservation efforts today.

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