DDT and the Recovery of the Bald Eagle on the Channel Islands, CA
So whatever happened to the infamous pesticide DDT after it was banned for use (though ironically not production) in the US in 1972? Unfortunately it is still with us, though we are seeing vast improvements in the recovery of many populations that were once crippled by this toxic chemical. This pervasive pesticide has been known for decades to cause weak eggshells in avian populations, which crippled reproduction in many species, and threatened with near-extinction to the national bird of the United States in the contiguous 48 states, had it not been banned.
Fortunately, the bald eagle has made a remarkable recovery across the United States since the 1970s. In one such case, during the 1950s and early 1960s, millions of pounds of DDT and PCBs were dumped off the coast of Los Angeles, CA causing the decimation of a number of marine-based feeders, including the brown pelican, peregrine falcon, and, of course, bald eagle, among others. A legal settlement with Montrose Chemical Corporation and other industrial sources generated the funding to reestablish the bald eagle population on the Channel Islands off the coast of southern California.
during the 1950s and early 1960s, millions of pounds of DDT and PCBs were dumped off the coast of Los Angeles, CA
To this end, the Institute for Wildlife Studies (IWS) was contracted to begin a reintroduction project, first on Catalina Island in 1980, to which there have been significant challenges in reproduction. Catalina reached its greatest milestone since the birds went extinct on the island in 2007 when it saw the first of its own wild-born chicks. before which eggs were artificially incubated to prevent the breaking of tender eggshells.
In 2002, this reintroduction effort was extended to Santa Cruz Island, which is located further from the spill source with the hopes of greater breeding success. On Santa Cruz, 61 eagles were released as fledglings over 5 years as part of a feasibility study. In 2006, Santa Cruz successfully hatched its first two chicks in over 50 years. After fledging just four chicks over four years including more nesting failures than successes, 2010 showed its first significant promising recovery of the bald eagle population with six chicks successfully fledged and just one nest failure.
For more information on the Channel Islands and the recovery effort, please check out: