By Frank Hein
Conservancy Director of Education
Bald eagles aren’t newcomers to Catalina Island. They’ve been documented to have been on the Island since pre-Columbian times, when the only humans on Catalina were the Tongva Native Americans. But, by the mid-1950s, bald eagles disappeared from Catalina and Southern California as victims of pollution from the synthetic pesticide DDT.
By Frank Hein
Conservancy Director of Education
Bald eagles aren’t newcomers to Catalina Island. They’ve been documented to have been on the Island since pre-Columbian times, when the only humans on Catalina were the Tongva Native Americans. But, by the mid-1950s, bald eagles disappeared from Catalina and Southern California as victims of pollution from the synthetic pesticide DDT.
Fortunately, the story didn’t end there. Since 1980, the Institute for Wildlife Studies (IWS) worked tirelessly to bring this species back. The Catalina Island Conservancy supported the work by providing funding in the eagle project’s early years, land for an eagle enclosure, full access to Catalina’s wildlands and logistical support.
The first step in the eagle’s comeback was to bring six chicks to Catalina from wild nests in the Pacific Northwest. The IWS recovery team raised the chicks in artificial nesting sites called “hacking towers,” which protected them from other birds, and kept the chicks from bonding with their human surrogate parents. Between 1980 and 1986, the team released 33 bald eagles on Catalina. And, happily, some found Island partners and became breeding pairs. By 1987, a few of the pairs had laid eggs, but the eggs were too fragile and broke in the nests. Weakened eggshells are a typical result when DDT is prevalent in the environment. Studies showed that DDE, a “metabolite” of DDT, was found in the eggs at elevated levels.
Beginning in 1989, to keep fragile eggs from breaking, the recovery team began removing them from the nests and incubating them in a controlled environment. To keep the birds in nesting mode, the team replaced the real eggs with replica eggs. You can see one in the Nature Center at Avalon Canyon. Much of this was accomplished by dangling a team member from a helicopter by a rope! Dr. Peter Sharpe, the lead biologist for the project, took significant risks to help this species recover. If hovering from a rope under a helicopter and swapping eggs – and potentially incurring the wrath of sharp-taloned parents – aren’t the riskiest thing a person can do, they’re certainly among a wildlife biologist’s the top ten!
While adult eagles incubated the replicas, the real eggs were being hatched in incubators at the Santa Cruz Predatory Bird Research Group at the University of California, Santa Cruz, and at the San Francisco Zoo. After hatching, the chicks were placed back in their nests and the replica eggs were removed by Sharpe. The adults, seeing chicks, simply assumed their young had hatched, and began caring for them.
In April 2007, Sharpe and Steffani Jijon (also with IWS), made a bold move, deciding not to replace the eggs in two Catalina nests. They wanted to see if DDE levels had dropped sufficiently to allow the eggs to hatch without human intervention. The results marked a significant milestone in Catalina’s natural history.
For the first time in more than 40 years, most of the eggs were healthy. They hatched! This “Easter Miracle,” as it was dubbed (occurring Easter weekend, March, 2007), marked the turning point at which Catalina’s bald eagles became a self-sustaining population. Eaglets have been hatching naturally on the Island every spring ever since!
