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The Return of Portland's Peregrines

Many a traveler across Portland's Fremont Bridge has been distracted and delighted by the sight of a peregrine falcon perched atop a lamppost or slicing through the air at over 200 miles per hour, taking aim at an unsuspecting rock pigeon. For many it has become a part of their daily commute. However it is not a sight that any of us should take for granted.

Peregrine Female - Bob SallingerThe Audubon Society of Portland has developed a comprehensive program to help manage Portland's growing peregrine falcon population. Our current efforts include monitoring, educational outreach, and active protection of nest sites during the hazardous fledging period; in the past, Portland Audubon also conducted rehabilitation and captive rearing and release programs.

In 2001, the Oregon Department of Transportation contracted with Portland Audubon to conduct a six month-long study of anthropogenic impacts on urban peregrine nesting behavior. This report formed the basis for a proactive management plan that was developed by ODOT in 2003.

Introduction: Return of the Peregrine

Peregrine - Bob Sallinger
Peregrine - Bob Sallinger

Many a traveler across Portland's Fremont Bridge has been distracted and delighted by the sight of a peregrine falcon perched atop a lamppost or slicing through the air at over 200 miles per hour, taking aim at an unsuspecting rock pigeon. For many it has become a part of their daily commute. However it is not a sight that any of us should take for granted.

Widespread use of the pesticide DDT during the 1940s, 50s and 60s caused peregrines and other top-of-the-food-chain predators such as bald eagles and osprey to lay eggs with thin eggshells. The eggs would break during incubation, leading eventually to a crash in the population.

By 1970, the American peregrine falcon (Falco peregrinus anatum) was almost completely extirpated from the continental United States. There were no known nest sites east of the Mississippi River and only a handful in the western United States.

Peregrine populations in Oregon were destroyed; by 1970 there were no peregrine falcons known to be nesting anywhere in the state. The listing of the American peregrine falcon under the Federal Endangered Species Act in 1973 and the banning of DDT in 1972 were the first steps on the long road to recovery.

Natural restoration of populations was augmented by an intensive captive rearing and release program. Captive-raised peregrines were released on Mt. Hood and at several locations in the Columbia River Gorge.

In 1980, the restoration effort began to pay off: peregrines were discovered nesting at Crater Lake. Peregrines first began appearing on Portland's urban landscape in the late 1980s. A pair took up temporary residence on the Lloyd Center Towers.

Attempts were made to induce nesting by placing of nest boxes on the buildings. However, no nesting attempts were documented and the pair eventually disappeared.

In 1993 a new pair of falcons was sighted regularly on Portland's Fremont Bridge, but again no nesting occurred. The pair did remain near the bridge throughout the summer and the ensuing fall and winter.

In April of 1994, biologists finally observed the moment they had been awaiting. The peregrine pair was observed entering and departing a platform under the lower deck on the east end of the bridge, a clear indication that they were incubating eggs!

An Expanding Urban Peregrine Population

Today, peregrine falcons nest at 11 different locations within the city limits of Portland, and our urban peregrines comprise six percent of the known nesting peregrine population in the state of Oregon.

The adult male peregrines at two urban sites, Saint Johns and Abernethy Bridges, are birds that originally fledged off of the Fremont Bridge. In 2001, Portland nest sites fledged 15 youngsters in a single season!

However, the challenges continue. Peregrines across the Oregon landscape continue to face real challenges to their long-term recovery. DDT has an extremely long half-life and pesticides that were sprayed decades ago continue to linger in our environment to this day.

Although their numbers have increased, Forest Service Peregrine Specialist Joel Pagel reports that every nest site he has entered in the Pacific Northwest continues to show levels of eggshell thinning higher than that prior to the use of DDT.

On the local front we have at least one nest site that faces serious contamination issues. An addled egg from the Saint John's Bridge collected by Joel Pagel in 1996 contained very high levels of DDT, dieldrin and PCBs, the origin of which most likely is derived from a nearby superfund site.

The biggest challenge in the urban environment continues to be managing the potential for human disturbance.

Ongoing educational outreach has created a community with a high level of both awareness and appreciation for the falcons. Local businesses, agencies, and individuals have voluntary altered their practices to best accommodate their winged neighbors. They have provided additional eyes and ears to help sound the alarm when either deliberate or inadvertent disturbance occurs.

Today, residents of the Portland metro area can look skyward and see the silhouette of a peregrine falcon slicing through the clouds.

Visitors to the narrow strip of greenway that runs along the west bank of the Willamette River beneath the Fremont Bridge or to Cathedral Park beneath the east end of the Saint John's Bridge can observe peregrines going through their nesting cycle.

Although peregrine means "wanderer" and peregrines are known for migrating huge distances, our urban peregrines tend to be year-round residents and are likely to be spotted near the bridges at any time of the year. It is a vision that we came close to losing forever, and one that we should never take for granted.

For a personal account of Portland Audubon's peregrine work, read Ken Barron's 2003 "A Look Back: Memoirs of a Peregrine Hack Site Attendant."

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