– by Mila Stroganoff
How did we go from a historical figure of 250 Peregrine Falcon (Falco peregrinus) pairs in California to 2 pairs in 1970? How did we take a much-revered bird and practically make it globally extinct within the span of twenty-five years? The answer comes with the further development of chemicals during WWII, especially DDT. After the war it was thought to be a miracle insecticide. It was used everywhere with no idea of its consequences. DDE, a breakdown product of DDT, negatively impacts the female reproductive system in birds and does not allow calcium to form in the body, creating thinner eggshells, much thinner, so that the eggs come out deformed, or the mother hen cannot incubate them because her weight destroys them. These are the consequences of DDE.
Dr. Doug Bell in “The Peregrine’s Saga” takes us on a most informative and fascinating story of the peregrine falcon from its healthy global distribution to almost complete extinction to full recovery. His lecture was a tour de force, but so was the battle to save Falco peregrinus.
According to Indigenous Californians and North American societies, we humans were created by “Wek-wek” (the Peregrine Falcon) and Coyote Man and Condor Man, and they then provided humans with the natural resources we would need to live and prosper. Perhaps it was only fitting, that as we owed the peregrine falcon our very existence, it was our responsibility to save it.
To save the peregrine falcon, scientists turned to the Art of Falconry practiced by the royal societies of Europe in the Middle Ages. They took the eggs laid by the hen, placed dummy eggs, and then two weeks later returned with two-week hatchlings. These little birds were accepted, fed, and cared for by the peregrine parents.
But it was not as simple as that. It took decades for scientists to realize what was happening to the population numbers of peregrine falcons, ospreys, and bald eagles and why. They needed scientific data and proof. However, before the advent of DDT, scientists were notified of the shooting sprees that were occurring on Hawk Mountain in Pennsylvania from 1932 – 1934 that killed thousands of peregrine falcons. A slaughter of unprecedented proportions was going on. Hawk Mountain was purchased and turned into a sanctuary and a warden hired.
Rachel Carson, a biologist, author of Silent Spring published in 1972, analyzed the peregrine count per hour every year from 1948 -1960. She read, studied, and assembled countless reports of the effects of numerous chemicals being used in agriculture and everyday life. She hypothesized that DDT prevented birds from breeding. Silent Spring was the bellwether that stated in no uncertain terms that widespread application of pesticides and their consequences would indeed result in there being no birds. She was vilified but stood her ground and against countless odds was proven right.
James J. Hickey at the University of Wisconsin held an international conference in Madison, Wisconsin in1965 regarding peregrine falcon populations. In 1967 British researchers verified that DDE does not allow for calcium to bind, creating thin eggshells inside the female raptors. Dr. Dan Anderson in the journal Science, wrote an article about chlorinated hydrocarbons and eggshell changes in raptors and fish-eating birds. He had measured egg thicknesses from 1700 eggs from 39 museum collections. In 1970, Derek Ratcliffe published peregrine eggshell data for Britain and stated that an 18 percent or higher reduction of eggshell thickness was the tipping point.
Finally, DDT was banned in the United States in 1972.
The captive breeding and release program took place from 1974 – 1992 in California. In 1990 there were approximately 100 nests. We are currently at over 300 pairs in California, but the carrying capacity is not yet known. Peregrines reside in the San Francisco Bay Area in both natural settings (20) as well as anthropogenic settings (27) for a total of 47 nest sites. Peregrines use a scrape with a ledge for a nest unless they take over another bird’s nest. However, the fledglings need help in urban settings, sometimes multiple times over, when they attempt to fly and end up somewhere unexpected and cannot make it back to their nest.
The peregrine falcon is the fastest bird, the fastest vertebrate clocking in at 242 miles per hour when diving in a stoop and showing off its prowess during the mating period. They also love to eat pigeons, so let us have kinder thoughts for pigeons. We have had success with reintroducing condors and peregrine falcons to the wild, but our successes are few compared to the many losses of biodiversity occurring in the world today. Let us hope that we have more successes in preserving our natural world.
Here are some websites that Dr. Doug Bell asked me to include in my article.
Check the following YouTube website to determine flying speed:
https://www.youtube.com/watch?v=5uy84N8CjR0 (National Geographic)
Research continues and check the following web site:
Check this website with camcorders at UC Berkeley: