History:
In the 1960s and 1970s the park's colonies of California brown pelicans faced extinction. In 1970 on West Anacapa Island, only 552 nesting attempts were made and only chick survived. Scientists pinpointed the pesticide DDT flowing from mainland sewers into the sea as the cause. When the pelicans ate contaminated fish, DDT disrupted their reproductive systems. DDT altered the birds' calcium metabolism, resulting in egg-shell thinning. The egg shells were so thin that they broke under the parent's weight resulting in reproductive failure.
The federal government listed the brown pelican as an endangered species in 1970, the state of California listed it as endangered in 1971, and DDT was eventually banned in 1972. The fight to save these birds led to a remarkable recovery. The park's breeding populations have steadily increased since 1980 and this subpopulation is now believed to be fairly stable. On Anacapa Island from 1969-1984, average colony size was 900 nest attempts per year.Strong increases in both productivity and nest attempts were observed in the mid 1980s, and the Anacapa colony has produced a mean of 4,600 nests per year during 1985-2006.
@4rky I was 16 at this time and this was my first awareness of human killing off an animal causing it to be extinct it made me so sad,that's way I am now so happy
February 22nd, 2024
Leave a Comment
Sign up for a free account or Sign in to post a comment.
Ian
Interesting history and great that they were able to be saved from being lost altogether