Date: August 8, 2016
Source: University of California
- San Diego
Biologists have discovered high
levels of pesticides and other contaminants from marine mammals in the tissues
of endangered California condors living near the coast that they say could
complicate recovery efforts for the largest land bird in North America.
"Even though marine mammals
are a potentially abundant food source for condors, they might not be that safe
to eat," said Carolyn Kurle, an assistant professor of biology at UC San
Diego and one of the senior authors of a study published this week in the
journal Environmental Science and Technology that found high levels
of persistent contaminants in California condors inhabiting the Central
California coast when compared to inland condors.
California condors, vultures that
feed on the carcasses of dead animals, were driven to near extinction in the
1980s, but their population has grown to over 400 birds today due in large part
to the California Condor Recovery Program's efforts. However, condors are not
out of the woods yet. Research has demonstrated that lead poisoning from
feeding on carcasses contaminated with lead-based ammunition is the principal
threat preventing condor recovery.
Some California condors that were
re-introduced into the wild in recent decades as part of recovery efforts
supplement their diet with carcasses of marine mammals, which are less likely
than land-based animals to contain lead in their tissues.
Because marine mammal carcasses
can be an abundant food source for coastal scavengers and are thought to have
helped prevent the extinction of California condors at the end of the last ice
age, 11,700 years ago, biologists welcomed this type of ocean-front dining as a
likely boon to the condors' recovery efforts.
