• 
• 
• 
• 
• 
• 

		Nature Conservancy Magazine: Winter 2006 Nature Conservancy Magazine Restoration Takes Flight Up Close Minding the Gap Potomac BioBlitz Nature Stories Podcast Nature Landmarks Nature Books Nature Travel Nature Preserves Subscribe Previous Issues

Restoration Takes Flight

Page 2

Digital photo essay: Santa Cruz Island Fox (new window, Flash plug-in required) Photo © Miguel Fairbanks   •  Santa Cruz Island, California • The Island Fox Recovery Program • Channel Islands National Park   • Institute for Wildlife Studies: Eagle video - Banding Day, June 2006 (Quicktime movie, 5.5 MB)     • Institute for Wildlife Studies: Eagle video - Chick being fed a fish (Quicktime movie, 467 kb)   • The Nature Conservancy's Invasive Species Initiative

The Conservancy launched an aggressive plan to save the island. Working with the National Park Service, which manages four of the Channel Islands and owns 24 percent of Santa Cruz Island, the Conservancy adopted recovery programs that include reintroducing bald eagles, eradicating feral pigs, breeding island foxes in captivity and, to protect the foxes, relocating the golden eagles. Each project addresses a distinct threat, yet each success builds on the last, helping to restore the whole island.

On this late spring day, when whales are spouting in the glassy waters that surround the island, it is the eagles that are commanding the most excitement.

The chick suddenly stirs and begins flopping about the nest. “It’s in the stage where its body is too big for its mind,” says Chris Little, a field technician monitoring the nest for the Institute for Wildlife Studies, a nonprofit contractor doing much of the fieldwork. Within a few weeks, the chick will be hopping to lower branches on the bishop pine that supports its nest. By midsummer, it will be flying.

Like many of the threats to ecosystems worldwide, the problems that plague Santa Cruz began innocently enough. DDT was developed during World War II to combat disease-spreading mosquitoes. It was effective. But by the 1960s, DDT was the focus of public outrage after Rachel Carson’s Silent Spring documented its impact on bird reproduction. The bald eagle, America’s national symbol, was among the species hardest hit.

The United States banned most DDT use in 1972, but that was too late for the population of bald eagles that had nested on Santa Cruz Island for millennia. Seventy miles across Santa Monica Bay in Torrance, the Montrose Chemical Corp. was one of several companies that had been manufacturing DDT and other chemicals since the late 1940s.

The company dumped toxic wastewater into the Los Angeles County sewer system and the Pacific Ocean. Two decades after the ban, scientific surveys found more than 100 tons of DDT in ocean-bottom sediments off Palos Verdes Peninsula.

Sunset along Santa Cruz Island’s Pelican Trail © Miguel Fairbanks

The effects on the Southern California marine ecosystem were devastating. The poisons passed from the soil to aquatic plants and on to crustaceans, fish and birds. Each step up the food chain increased the level of DDT in an insidious process called bioconcentration. On Santa Cruz, the bald eagles, which depend on fish as their primary food source, were at the top of the food chain.

DDT didn’t kill the eagles outright but rather altered their calcium metabolism in a way that weakened their eggshells. Some eggs were crushed in the nest. Others failed because they were too thin to hold enough moisture for the developing chick. By the 1960s, bald eagles had vanished from Santa Cruz Island. 

<<   1  |  2  |  3  |  4  |  5   >>