CHANNEL ISLANDS NATIONAL PARK — A seabird known as the brown booby that is usually tropical or subtropical has nested for the first time in Channel Islands National Park off the coast of Southern California.
The discovery announced by the park Tuesday means the bird appears to have extended its range farther north than previously seen. The Channel Islands lie west and south of Los Angeles.
Biologists last week discovered four nests and 102 individual brown boobies on Sutil Island, a tiny island just off Santa Barbara Island, a park statement said.
Adult birds appeared to be either incubating eggs, tending to young in the nests or fending off attacks by western gulls.
The discovery means 14 species of breeding seabirds now rely on the park, showing the importance of the Channel Islands as critical seabird habitat, Superintendent Russell Galipeau said.
The birds rely on marine resources for food and the offshore isolation helps keep them safe from predators, he said.
Brown booby populations have declined elsewhere in the world on islands where predators have been introduced, the park said.
The bird is known for making spectacular dives for surface fish from heights of up to 50 feet. They lay their eggs on bare ground on islands and then make nests with sticks, rocks and vegetation.
Expansion of the brown boobies' range has been noted since the 1990s, when the birds moved northward from the Gulf of California and the Pacific coast of Mexico to the Coronado Islands in the ocean off northern Baja California.
According to the park, this movement coincides with changes in ocean conditions associated with the El Nino ocean-warming events.