VENTURA COUNTY, Calif. - A rare species of seabird known as the Brown Booby has been discovered nesting on the Channel Islands off the coast of Ventura County for the first time.
This discovery signifies a significant northward expansion of the Brown Booby's breeding range, which was previously believed to be confined to tropical or subtropical areas.
Biologists discovered four nests and 102 individual birds on Sutil Island off the southwest end of Santa Barbara Island during a survey on Nov. 3, 2017, according to a news release by Channel Islands National Park.
Adult birds appeared to be either incubating eggs or tending to young in the nests, according to the news release.
"This discovery, once again, demonstrates the importance of the Channel Islands as critical seabird habitat," said Channel Islands National Park Superintendent Russell Galipeau. "This makes for a total of 14 species of breeding seabirds, birds that rely upon the rich marine resources and the isolation of these offshore islands to provide food and undisturbed nesting grounds safe from predators."
Brown Boobies are known for making spectacular plunge dives from up to 50 feet high to feed on surface fish.
They typically nest on islands, laying their eggs on the bare ground and making nests with sticks, rocks, bones, and vegetation for protection. Brown Boobies usually winter far out to sea, which is why this discovery is such an important find for biologists.
The seabird species appear to be extending their range northward since the 1990's when they first migrated to the Coronado Islands of Baja California from the Gulf of California and Pacific coast of Mexico.
"This expansion of their range coincides with shifts in oceanic conditions with warmer waters and changes in prey availability associated with recent El Nino events," read the Channel Islands National Park news release.
Biologists are in agreement that Brown Booby populations have declined over the years due to habitat degradation on islands where introduced predators have wreaked havoc during the birds' nesting period.