Losing Biodiversity—chapter 6:
The Predatory Bird Research Group is located at the Long Marine Lab of the University of California, Santa Cruz in California.
This story combines mystery, high adventure, and camaraderie, all dedicated to a creature of sky and cliffs. In the 1970’s, a small team of California biologists set out to save the western peregrine falcon from what looked like certain extinction. There were only a few breeding pairs left in the state and the birds were almost gone from North America.
As I searched for the temporary portable office at the edge of the University of Santa Cruz campus in 1999, I felt excited about this opportunity to learn from scientists who have studied falcons for more than twenty years. Brian Walton, who coordinates the Predatory Bird Research Group (PBRG) described how he became hooked on peregrine falcons at an early age. “I went to Aviation High School near the Los Angeles Airport. Our mascot was the falcon...As fate would have it, I was assigned a term paper in the ninth grade that required research on falcons... When I graduated from high school there was only one pair of peregrines known to nest in California. The nest was on Morro Rock, so I moved there and enrolled in the local college.”
A chance meeting at Morro Rock in 1973, with ornithologist (person who studies birds) Tom Cade, encouraged Brian at age 22 to begin his career in falcon restoration research. Professor Cade had established a breeding colony of peregrines at Cornell University in New York and was working to increase peregrine research and restoration efforts. With the backing of the late Professor Kenneth Norris at UC Santa Cruz, and veterinarian James Roush, the Santa Cruz Predatory Bird Research Group was born.
Brian recalled the pressure in the early days to find answers to practical questions such as best hatching temperature and rearing conditions. At first, peregrine eggs were hatched at his home in hand crafted incubators set up in bureau drawers. So few birds remained in the wild that every egg was precious. A breeding program was also underway in Boise, Idaho, and the researchers shared information and birds as they developed methods of hatching, rearing, and releasing young peregrines back into the wild.
A message that Brian has shared whenever he has the opportunity to talk with young people is how a few people who are knowledgeable and persistent can really change the chances of a species’ survival. “Where there is a will there is a way,” he commented, while describing how teamwork brought the peregrine back from near extinction.
The research efforts that paved the way for the peregrine breeding programs began in the 1950’s when scientists like Tom Cade wondered why bird populations were in decline. Old newsreels from the 1940’s show tanker trucks traveling through neighborhoods and parks spraying DDT on lawns and ponds to wipe out mosquitoes. Health officials hailed DDT as an amazing new chemical that didn’t seem to harm large animals, but was very effective in killing insects. By the 1950’s DDT was being used throughout the tropical regions of the world in an attempt to wipe out malaria and other mosquito-born diseases.
Rachel Carson was among the first scientists to alert the public to the worldwide decline in bird species and other wildlife. Her careful reviews of field and laboratory research implicating DDT were presented in her book Silent Spring, published in 1962. At first she was belittled as a “nature nut,” and “bird watcher” by the chemical industry, food companies, and some government agencies, but soon her hypotheses were vindicated by the growing body of research evidence.
In following years, DDT and eleven other chemical pesticides Carson warned about were banned or tightly restricted. Extensive laboratory and field research revealed how DDT affects organisms, and how it is transported through the food web of ecosystems to cause declines in wildlife populations. Brian Walton read Silent Spring in high school and became a biologist so he could keep looking for peregrines.
Scientists documented that birds migrating to the southern US, Central and South America during the winter were feeding on grains and insects that had been sprayed with DDT. The DDT was converted to DDE, which binds readily with fatty tissue and remains in the body until the fat reserves are used by the animal. Birds that were stressed during migration often died when their bodies converted the fat, releasing the DDE.
Scientists also discovered that the low breeding success of many species of birds was due to DDT. The pesticide was found to cause eggshell thinning in peregrine falcons and many other predatory birds such as brown pelicans, bald eagles, and osprey. Bird predators that fed on contaminated wildlife were accumulating large doses of DDE. Accumulation of DDE in the fatty tissues disrupted calcium metabolism and caused thin-shelled eggs that often broke as the parent sat on the nest.
August 20, 1999, this champion sky diver was down listed from the Endangered Species List, to a threatened species, its numbers in California at more than 150 breeding pairs. Brian Walton pointed out that the success story was the result of the dedicated teamwork of hundreds of scientists and private citizens who performed a variety of tasks that ranged from rock climbing to analysis of egg shells and tissue samples.
Information and successes were generously shared between the three peregrine breeding centers located at New York, Idaho, and California. Captive birds were donated as breeders, and citizens who maintained guardian watches on wild nest sites contributed thousands of volunteer hours.
Janet Linthicum reminisced about her first year on the job with PBRG. She was a self-proclaimed science geek in high school, mainly interested in chemistry and physics. As a freshman at UC Santa Cruz, she especially liked her wildlife biology course by Professor Todd Newberry, and decided to apply to Brian Walton’s ad for a Peregrine Nest Site Assistant.
Her job description stipulated long hours, rigorous conditions, risk, and 11 months in the field each year, all for a tiny salary. She began work in 1983, in northern California as a nest guard, observing the birds, and protecting the nest from falconers. Camped alone in a tent, high on a bluff, she hauled water to her observation point. That spring, it rained constantly, and she read Fyodor Dostoyevsky's novel, Brothers Karamazov, three times!
Despite many years of strenuous field work and laboratory research involved with incubating eggs in the lab, including night shifts, 7 days a week for 4-5 months at a time, Janet has never gotten over her love of peregrines, nor tired of seeing them in the wild. She commented that “wildlife biology and the concept of evolution has provided endless room to think about origins and to speculate.”
Her exciting career has enabled her to work throughout the west on population recovery efforts for peregrines, bald eagles, and the California Condor. She has become a radio-telemetry specialist, and database specialist in the course of her work, and is co-author of the “Management Manual for Peregrine Falcons at the Eyrie”.
Janet is concerned that young people become interested in evolution and aware of the time involved for species and habitats to emerge. Often her free time is devoted to educating the public about the values of wildlife and habitat. “It seems wasteful to wipe out so many years of evolution for a temporary gain,” she points out.On-Going Research Questions
The Santa Cruz Predatory Bird Research Group continues to expand its research efforts. Here are some of the current questions the scientists are investigating:
What factors influence how local and migrating bald eagles use California habitats?
How effective are satellite telemetry transmitters in revealing the migratory patterns and habitat use of bald eagles?
How many burrowing owls nest in Santa Cruz and Santa Barbara counties and what are their habitat needs?
What factors influence golden eagle mortality from wind generators in the Altamont Pass Wind Resource area of California?
How can predation by peregrines on other endangered species like least terns, marbled murrelets, and snowy plovers be reduced?
How are environmental levels of DDT along the California coast affecting the breeding and survival of peregrines?New Research Facilities
The many successes of the Predatory Bird Research Group (PBRG) resulted in a grant from the state to build a permanent “state of the art” facility at the Long Marine Lab, University of California, Santa Cruz.