In the coastal redwoods of central California, scientists trying to unravel the mystery surrounding the reproductive problems of dozens of endangered condors think they have uncovered the culprit: the long-banned pesticide DDT.

Kelly Sorenson, executive director of Ventana Wildlife Society and a co-author of a new study on Big Sur-area condors, says researchers who spent six years studying their reproductive problems have "established a strong link" to DDT in the birds' food: dead sea lions.

The peer-reviewed paper is being published this month in the University of California journal The Condor.

The soaring scavengers were reintroduced to Big Sur in 1997 after a century-long absence and quickly started eating dead marine mammals, whose blubber often has high levels of DDT, a pesticide banned in 1972.