A tropical bird known for its webbed feet and plunging dives has been found nesting for the first time in Channel Islands National Park.

Late last week, biologists spotted 102 brown boobies and four of their nests on a small, rocky islet off Santa Barbara Island.

About 54 miles off Ventura, Santa Barbara is the smallest of five islands in the park and its southernmost point.

“It's a pretty neat occurrence,” said David Mazurkiewicz, a seabird biologist with National Park Service.

He and other biologists plan to keep tabs on the new residents, checking to see if nesting numbers increase or when they might be able to spot larger chicks, he said.

At this point, it’s too soon to say how long they’ll stick around.

This could be just a small number of the birds deciding to try nesting up this way.

Or, Mazurkiewicz said, the sightings could mean conditions have pushed the species to move north.

Typically, a change in seabird patterns is resource-driven, he said.

“If they're able to set up and breed, there is probably enough resources around,” he said.

That means the brown boobies have found enough food to eat and places to roost for them to nest here.

The birds first were spotted in this area a few years ago as weather patterns brought much warmer waters offshore and prey to eat.

Researchers have been on the lookout for possible breeding pairs, but last week was the first documented sighting of the birds nesting here.

Adults appeared to be incubating eggs or possibly caring for young chicks on the small island called Sutil.

They were hunkered down in the nests, Mazurkiewicz said. Some used their bills to poke around a bit.

One pair swapped nest duties as the biologists watched, and another of the brown boobies chased off some gulls getting too close, he said.

The nests appeared to be dry vegetation cobbled together near the cliff face.

Brown boobies, which eat squid and other fish, lay their eggs on the ground and then pull sticks, rocks, bones and vegetation around them.

They can dive from 30 to 50 feet up in the air, heading straight down like a bullet into the water.

They generally winter far out at sea.

In the late 1990s, the birds also migrated north, a move that seemed to coincide with warmer waters, the National Park Service said.

Back then, they extended their range north to the Coronado Islands off Baja California.

With last week’s discovery, the remote, offshore Channel Islands National Park now has 14 species of breeding seabirds.

"This discovery, once again, demonstrates the importance of the Channel Islands as critical seabird habitat," said Russell Galipeau, superintendent of the national park.