Dive Dry with Dr. Bill

#196: Bald Eagle... Almost a Turkey!

When I first came to Catalina to teach at the old Catalina Island School for Boys, the school had a dormitory named Bald Eagle (which some of the students referred to as "Bald Ego"). There was a beautiful custom Catalina tile plaque to identify the dorm (as there were for the other dorms like Flying Fish and Torqua). In the days before World War II, students like Packy Offield's father Wrigley Offield, Hank O'Melveny and others frequently reported sightings of these beautiful birds soaring over the island. The eagles disappeared by the 1950's and 1960's due to the contamination of waters near Los Angeles with DDT and DDE. Although DDT was banned in the U.S., American corporations still sell it in Central and South America. I guess we also export our pollutants... a strange way to treat our fellow Earthlings and critters.

I did see one bald eagle above China Wall in 1976, probably a stray here to celebrate our country's bison-tenial... er, bicentennial. Other than that sighting, the only eagles present on the island were a few golden eagles which took over after the bald eagles disappeared. As far as I can tell, golden eagles disappeared once the the Institute for Wildlife Studies' (IWS) bald eagle reintroduction program began in 1980. These two species appear to exclude one another, perhaps due to competition for nesting space or possibly some type of food.

When I became Vice President of the Conservancy in charge of its conservation, education and scientific research programs, I had some good talks with Dave Garcelon, President of the IWS. I had serious doubts about the value in continuing the bald eagle reintroduction program. DDT and DDE continue to linger in the food chain long after it was banned. The IWS discovered that the eagles were eating higher on the food chain than presumed (seagulls instead of fish), so the toxins were biomagnified, present in concentrations much higher than expected. This pollutant interfered with the production of egg shells strong enough to survive incubation by the adults. To ensure the young eagles survived required a very labor and money intensive program to remove the eggs, incubate them in hatching facilities and return the newly-hatched chicks to the nest. Given that this seemed a program doomed to only partial success, at least at this time, I questioned its value.

Dave convinced me that the IWS carried the brunt of the funding, and that the Conservancy provided largely logistical support. It also provided scientists with some important information about the effects of DDT and DDT on bald eagle reproduction. When federal agencies decided to shift funding from the Catalina project to other programs on the more northern Channel Islands, also conducted by the IWS (a very reputable conservation organization), I was one of the few who thought the move appropriate.

In late May a pair of young eaglets successfully hatched on Santa Cruz Island off Santa Barbara. The last successful hatching in the entire Channel Islands region was in 1949 as far as I can tell. The fact that the reintroduction program up north has already achieved some success suggests that the assumptions the federal agencies and I made were correct. DDT and DDE concentrations in the food chains there apparently are lower than those off our waters... or perhaps the eagles there are being more industrious and tackling more challenging prey than the seagulls with their higher loads of the pollutants.

The bird was declared our national emblem by the Second Continental Congress in 1782 because it was considered unique to our country. They were wrong in considering it a national endemic since they are also found in Mexico, and Alaska which was in Russian hands at the time. Founding father Benjamin Franklin considered bald eagles a "Bird of bad moral Character" as he wrote to his daughter two years later. Modern students of animal behavior would consider this a bit too anthropomorphic a description. However, Franklin considered them lazy thieves, preferring to rob other more diligent hunters like the osprey of their catch. He also considered them cowards since smaller birds would often mob them and drive them away. The "discoverer" of electricity felt the turkey should be our national symbol instead. I must admit that I think turkeys are a much tastier choice, since bald eagle tastes remarkably like spotted owl or giant sea bass from what others have "reported."

We didn't treat our national emblem very well. In the early 1700's the population was estimated at 300,-500,000 birds, but dropped to less than 10,000 nesting pairs by the 1950's. Even in the mid-1800's they were seen fishing off Manhattan and eating their kill in Central Park. But early settlers saw them as competitors for their fish and fowl food, and predators on their livestock, so they killed them for sport. Of course the original "Native" Americans also hunted them for their feathers for ceremonial headdresses and their talons (just ask Richard Harris!). Early residents of, and visitors to, the island treated them the same way. They were hunted, along with our unique island foxes, and a carcass was often displayed on the outside of the old Hotel Metropole on the Fourth of July. A strange way to treat our country's symbol, don't you think?

Bald eagles are commonly associated with bodies of water including rivers, lakes and oceans. I have observed them fish in the waters of the Gulf of Mexico from my grandparent's home in Florida, and while camped on the northern tip of Vancouver Island, British Columbia. Although I don't expect to see one underwater, their association with it makes them an appropriate species for this column. After all, they do feed primarily on fish but will also take birds, turtles, muskrats, rabbits and snakes. Bald eagles need an "eagle eye" since they may fly as high as 10,000 feet. They may dive at speeds of 75-100 mph, but prefer to swoop down and catch fish with their talons.

Golden eagles are more land-based. Both will feed on carrion, including dead island foxes. However the golden eagle is known to kill and feed on living foxes, including the threatened populations on the northern islands. With our own island fox still recovering from the decimation caused by the outbreak of canine distemper in 1998-1999, we must be careful to ensure that golden eagles do not once again replace bald eagles on Catalina. Therefore it may be necessary to maintain adults of breeding age here to keep their relatives away. That to me offers a very valid reason for at least maintaining the species here until it is able to breed successfully as DDT and DDE levels in our food chains decline. Oh, and the loss of a few thousand seagulls wouldn't upset the patrons of some of our open air restaurants, would it?

© 2006 Dr. Bill Bushing. Watch the "Dive Dry with Dr. Bill" underwater videos on Catalina Cable TV channel 49, 10:00 AM and 5:00 PM weekdays. Please help me climb out of self-imposed poverty... buy my "Munching and Mating in the Macrocystis," "Great White Sharks of Guadalupe," "Calimari Concupiscence: Mating Squid, " "Playful Pinnipeds: California Sea Lions," "Belize It or Not: Western Caribbean Invertebrates, Fish and Turtles" or "Gentle Giants: Giant Sea Bass" DVD's. Yes, take Dr. Bill home with you... we'll both be glad you did!

Catalina bald eagle... a lazy thief but our national symbol.

This document maintained by Dr. Bill Bushing.
Material and images © 2006 Star Thrower Educational Multimedia