Story and Photographs by John Ehrenfeld, John Ehrenfeld Photography
Historically, Bald Eagle populations in California were widespread and abundant with evidence of their presence dating back to pre-Columbian times. But due to the synthetic pesticide DDT, hunting and habitat loss, by the 1960's fewer than 30 nesting pairs remained in California, all in the northern third of the State.
DDT was the primary cause, it was dumped into the Pacific Ocean in Southern California as part of the manufacturing process, eaten by fish and then consumed by Eagles. The toxic poison caused their eggshells to become too weak to survive incubation and the Eagle population plummeted and almost disappeared entirely in Southern California; specifically in traditional nesting areas on Catalina and the Channel Islands. Extinction was a real possibility.
Typically Eagles reach sexual maturity after five years, marked by their heads and tail feathers turning white. Historically, young California Bald eagles wandered throughout the Pacific Northwest states and British Columbia, hunting and exploring. Research has shown that after they turned five, they return to within a hundred or so miles of their natal nests to find a territory on or near a suitable lake or river to find a mate and start reproducing.
This story was not going to end badly, thanks to the heroic actions and dedication of a small handful of scientists, biologists and wildlife experts. Starting in the 1980’s, the ‘Institute for Wildlife Studies’ led by Peter Sharpe started working to reintroduce the Bald Eagle into California
The initial effort involved transporting six Eagle chicks to Catalina Island from their nests in the Pacific Northwest, where they and raised them in artificial nesting sites called hacking towers.
This was moderately successful as they released more than thirty juvenile Bald Eagles on Catalina Island and some even found mates when they were of age and a few laid eggs. But, the presence of DDT again meant eggshells were too fragile and broke in the nest. Another dramatic effort was needed and what followed was an inspiring example of what can happen when science, creativity and dedication come together.
So, starting in early 1989, the fragile eggs that were laid were immediately taken from their nests and incubated, while replacing them with look-alike wooden eggs. Well, after a few curious prods and pokes, the Eagles sat on the eggs as if they were their own. While this “faux” incubation played itself out over the typical thirty-five day gestation period, the real eggs were being incubated at the ‘Santa Cruz Predatory Bird Research Group’ and at the ‘San Francisco Zoo.’
After they hatched. the Eagle chicks were flown back to Southern California and placed back in their nests when the adults were hunting, while removing the wooden ones. The adult Bald Eagles, seeing chicks, assumed their young had hatched, and began caring for them normally.
This was an incredible effort that required adequate funding, countless volunteer hours and dedicated wildlife biologists, namely Dr. Peter Sharpe, who was often seen hanging from a helicopter to access the nests.
After years of this effort which successfully fledged many chicks, in April of 2007, Drs. Sharpe and Steffani Jijon decided not to switch out the eggs in two Catalina nests as a test, to ascertain if DDT levels had dropped enough to allow the eggs to hatch naturally. They did and this signified an important milestone contributing to their reintroduction into the wild in California.
Incredibly, eggs were healthy and hatched and each year has resulted in more and more Bald Eagles being hatched throughout California and accordingly, the population has grown rapidly.
Every winter, migrating transient Bald Eagles join hundreds of permanent residents in California numbering more than a thousand birds. One can now see them soaring overhead throughout most of the state, primarily in coastal areas or near large inland lakes and rivers that have abundant fish which is their preferred meal. They are majestic glorious birds who can live to be twenty-five to thirty years in the wild, mate for life and are firmly ensconced at the top of the food chain. Aside from being one of the endearing symbols of our nation, they are critically important to the circle of life in the wild.
So there you have it, some wonderful information about Bald Eagles in California. Do you have Bald Eagles in your state?
The floor is open. Tell us what’s happening in your birdy world!