

RICHMOND — A pair of big sea hawks called ospreys make their debut Wednesday as internet stars on video cams that web cast their nesting and highlight the comeback of the species around San Francisco Bay.

Taking advantage of unusually good view points from high up on a historic World War II maritime crane along the Richmond shoreline, two high-definition cameras will live stream the adult ospreys courting, laying and hatching eggs. Once the chicks hatch, their feeding and learning to fly will be streamed live, too.

Ospreys are fearsome fish hunters whose wing spans can reach five or six feet. They are very chatty and social around the nest with calls and coos.

“We are using the most advanced technology to make this majestic wild bird accessible in a way that no photographer could from the ground,” said Cindy Margulis, executive director of Golden Gate Audubon, organizer of the project. “We believe witnessing the life of an osprey family along our urban shoreline can inspire the whole community to protect ospreys and other Bay area wildlife.”

The live streaming is available as of Wednesday and can be viewed at http://sfbayospreys.org/. Viewers can see the birds at night, too, because the cameras use infrared photography.

Over the past 10 to 15 years, web cams of raptors such as eagles and falcons or other wild creatures have revolutionized how people watch wildlife. A webcam of a peregrine falcon nest on a ledge at San Jose City Hall attracted half a million views in its first week in 2007. No current figures are available.

A webcam of a bald eagles nest in the National Arboretum in Washington D.C. attracted 63 million views last year.

Until the web cams became available, scientists trying to learn of raptor habits had to do it the hard way perched with binoculars in hard-to-reach spots.

“We would spend long hours in the middle of nowhere. Now anyone can do it at their desk on their computer,” said Glenn Stewart, director of the Santa Cruz Predatory Research Bird Group, the organization behind the webcam at San Jose City Hall.

Margulis said the Richmond osprey webcam has an additional advantage: killer views of San Francisco Bay in the background.

Ospreys, to be sure, are the stars of the cam stage. Their dramatic dives to snatch fish out of bays, rivers and lakes are a prize catch for wildlife photographers.

Before the nesting season, crews placed two high definition cameras on a big stick nest ospreys had built on a Whirley crane near the Rosie the Riveter/World War II Home Front National Historical Park.

As expected, a male, since named Richmond, and a female, since named Rosie, showed up this February at the nest, paired off, and recently starting courting. Naturalists expect to see eggs laid within a couple of weeks, followed by a 36- to 42-day incubation. The chicks take about 50 to 55 days to learn to fly.

Marguiles said she hopes the attention from the osprey cams will motivate more people to help osprey by protecting or constructing nesting platforms, cleaning the Bay shoreline of litter and junk, and picking up fishing line osprey can get caught in.

In July 2013, an osprey chick hatched at the Whirley crane nest had to be removed so a wildlife hospital could cut it loose from fishing line wrapped around a branch in the nest. The chick recovered.

Osprey are making a big comeback along the Bay Area shoreline possibly due to improvements in water quality and shoreline habitat over the past 30 years. Bird experts also suspect eagles, another species on the rise, are driving osprey out of lake nests and forcing them to look toward the Bay.

The Bay shoreline had only one known osprey nest the early 1990s.

In 2012, there were 15 nests producing 30 chicks that learned to fly. In 2016, there were 26 nests that produced 51 chicks, said Tony Brake, a volunteer researcher with the Golden Gate Raptor Observatory.

Most of the nests are along the East Bay and Vallejo shoreline, where cranes, poles and other industrial equipment offer nesting platforms.

“It’s about a doubling in four years,” said Brake, a Richmond resident. “It’s a good sign. I think the cams are going to make people more aware of them.”

Osprey facts

Osprey: A large raptor that is the only North American hawk that feeds almost exclusively on fish.

Wing span: 59 to 70 inches.

Adult weight: 50 to 71 ounces.

Fishing skills: Ospreys catch fish on one of every four dives, making a catch about once every 12 minutes of fishing.

Frequent flier: An osprey may log 160,000 air miles in migrations over its lifetime of 15 to 20 years.

Nests: Contains two to three eggs on average. Stick nests can be 10- to 13-feet deep and three- to six-feet in diameter — easily big enough for a human to sit in.

Risks: Ospreys build their nests with sticks and other scooped-up materials, including fishing line. Unfortunately, the line can wrap around and injure the chicks.