Golden eagle
Golden eagle predation, discovered when foxes were radio-collared and monitored, proved to be the cause of the high mortality rates. The golden eagle was an uncommon visitor to the Channel Islands before the 1990s according to data gathered by Dr. Lyndal Laughrin of the University of California Santa Cruz Island Reserve, and the first golden eagle nest was recorded on Santa Cruz Island in 1999. Biologists propose that the eagle may have been attracted to the islands in the 1960s after the decline of the bald eagle. The golden eagle replaced the bald eagle and began to feed on feral pigs following the devastation of the local bald eagle population due to DDT exposure in the 1950s—the bald eagle would have deterred the golden eagle from settling on the islands while it subsisted on fish.