The Return of Portland's Peregrines
The 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
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 completely decimated; 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 and the banning of DDT, both 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, the largest effort of its kind ever undertaken. 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 to induce nesting were undertaken by the placement 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 that they had been awaiting. The 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 PCB's, 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 more information on the peregrines of Portland or the Peregrine Watch Project, contact Bob Sallinger at the Audubon Society of Portland at email@example.com.
A Look Back: Memoirs of a Peregrine Hack Site Attendant, 2003
When Bob Sallinger first mentioned this project to me, I became quite enthused about it. My duties would be to feed and monitor the young peregrines throughout the six weeks it would take for them to learn to hunt on their own. I envisioned all of this taking place at a beautiful remote site in the mountains. The hack box would be on a ledge of a cliff and I would be camping out in the forest with volunteers bringing me supplies once in a while. Reality turned out to be somewhat different.
Unable to locate a suitable site in the mountains, Bob elected to go with a hacking tower. Ridgefield National Wildlife Refuge provided the site, Bachelor Island, a flat island on the Washington side of the Columbia River with few trees, a raised dike around the perimeter and numerous wetland areas in the midst of hay and corn fields. The tower, constructed by Clark Public Utilities, was some 30 feet tall and nine feet square. One of the poles was equipped with climbing spikes for access.
The big day finally came, June 14th, and we banded the peregrines with color-coded bands. Black and Red were males, while White and Orange were females. Blue, a female that fledged prematurely from the Astoria Megler Bridge and could not be reunited with her parents, was added later.
The birds were placed in the hack box during a pouring rain and my six-week vigil began. For the first week the peregrines were fed quail delivered to them through a chute in the roof of the hack box. For an hour each day I observed the falcons through a peephole in the roof to ensure that all were healthy and getting an adequate share of the food.
A week later, we opened the hack box and set the birds free. Once the box was open, Black immediately bolted for the horizon. The others explored the tower platform. Now my work really began. I not only provided food for the birds, but also monitored them from sunrise to sunset. My days started before 5am and ended after 9:30pm. The temperature varied from 50F to 98F, and the wind blew so hard at times I had to tie a 10 pound bag of rocks to my spotting scope.
Two days after the box was opened, Red began making short hop flights from the tower railing to the top of the hack box and finally flew off at high speed and spent the night in a cottonwood tree. Orange and White slept and ate, and ate and ate. Black returned on the fourth day. I watched him stoop on a harrier (he missed) and then make a perfect landing on the tower. He was pretty hungry, but each time he attempted to eat, White, the biggest and a bit of a bully, would attack him until he finally gave up. Eventually, Black grabbed a quail and headed for the trees. As he crossed an open field near the observation site, he was attacked by a mature Bald Eagle that, after a short tussle, stole the quail and headed for the river. Black chased and harassed the eagle, but finally gave up and returned to the tower where he grabbed part of a quail and left for the trees. On June 27th a Red Tailed Hawk tried to steal food from the tower and scared both White and Orange into their first flights.
Five days after that, a pair of immature Bald Eagles attempted to steal food off of the tower but were immediately attacked by Black who chased them both off to the trees! By now the peregrines knew how to handle the local eagles and they quit hanging around. On July 8th, I saw White and Black make kills!
At the time of this writing, July 30th, all five peregrines continue to be sighted hunting and practicing their flying skills in the fields surrounding the tower. They take great delight in harassing Great Blue Herons and egrets. They return to the tower less and less frequently as they roam farther from the hack siteÑa sign that my work here is almost complete! Perhaps next year I will be at a site in the cool forest. If not, I'll probably be out on Bachelor Island with another crop of birds.
By Ken Barron