On the Fly – The National Bird Comes to Martinez

Here’s some nearly unbelievable local bird news: bald eagles have been spotted in Alhambra Valley. I’ve gone out looking for them a few times with no success, but a very reliable person with excellent vision tells me she’s seen them several times near the “T” of Alhambra Valley Road and Reliez Valley Road, the same location where there were last year. 

I never would have believed there were bald eagles (Haliaeetus leucocephalus) around here, but then one day on BART, of all places, I spotted one flying through Lafayette. It was probably flying home to the Lafayette Reservoir, and the Alhambra Valley birds may have been taking a break before heading home to the Briones or San Pablo Reservoir. Maybe they like to stop in at the lagoons up in the hills near the Alhambra Creek headwaters.

These huge birds can weigh as much as seventeen pounds, with a wingspan of eight feet or so. They will spend weeks or even months building a nest, working several hours a day. Then they use the same nest year after year, adding new sticks every breeding season and creating a structure as wide as nine feet that weighs as much as a ton. At about a month old, the chicks start jumping back and forth, in and out of the nest, increasing the distance until they are making short flights. While they are perfecting their flying, landing, and diving skills, their parents continue to bring food to them at the nest. Then they leave, and for the first four years of their lives, the immature birds are nomads, sometimes flying hundreds of miles in a day. In their fifth year they become sexually mature and reduce their range, once they’ve found a lifelong mate and started building a nest. Yes, I know, it sounds familiar.

In the 1700s there may well have been a hundred thousand breeding pairs of bald eagles in the lower forty-eight states, but even before we started using pesticides that destroyed their eggs, they had to contend with hordes of settlers crowding into their once spacious habitats, shooting and poisoning them for fear of what they might do to livestock. Actually, bald eagles prefer fish, but they will also eat gulls, waterfowl, carrion, and small mammals. They can lift about four pounds.

Although legislation was passed in 1940 to ban hunting, injuring, or capturing them, widespread use of the pesticide DDT pushed eagles even closer to extinction. By 1963 there were only about four hundred breeding pairs in the lower forty-eight—a decline of more than 99 percent in two centuries; now, thanks to the ban on DDT, the protections offered by the Endangered Species Act, and the efforts of restoration programs, there are more than nine thousand pairs. (In Alaska, where they are considered about as interesting as pigeons, the bald eagle population is about thirty-five thousand.) In 1995 the government moved the species from “endangered” status to “threatened”; in 2007 bald eagles were taken off the list entirely. They are still protected, however, and they are also still threatened, by such things as collisions with cars, lead ammunition in their prey, and wind farms.

An important element in the eagles’ recovery is their comfortable adaptation to a relatively new ecological niche, the freshwater reservoir. This year a pair on the San Francisco Peninsula—the first in almost a hundred years—drew plenty of attention at Crystal Springs Reservoir, and bald eagles have been nesting at the Del Valle, Lafayette, Briones, and San Pablo reservoirs for several years. They’ve also been seen at Lake Herman, near Benicia.

If you think you’re seeing a bald eagle, there’s a very good chance that you are. The contrast between their snowy white heads and tails and their dark bodies and wing feathers is unique, as are their huge yellow beaks. Don’t expect any shrieking or screaming, though; the bald eagle’s call is more like a chirping whistle. Females and males have the same plumage, but females are about 25 percent larger than males. Immature bald eagles are more difficult to identify, being dark all over with white speckles. They don’t get their full plumage till their fifth year and can be mistaken for golden eagles.

The bald eagle lives only on the North American continent, year-round in a few places (including the San Francisco Bay Area) and migrating between others—from the Gulf Stream waters and the redwood forests, as it were, to the far north. Its “fierce beauty and proud independence,” John F. Kennedy noted, “aptly symbolizes the strength and freedom of America.” Given the success of the species and our own recent history, maybe we should be looking to its resilience and resourcefulness for inspiration as well.

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You can see a live, rescued but non-releasable bald eagle at Walnut Creek’s Lindsay Wildlife Museum. And here’s a nice article, with photos, of two nesting eagles named Patriot and Liberty feeding their chicks at Redding’s Turtle Bay Exploration Park.