Come see herons, egrets nesting at Google’s Mountain View campus

Every year, dozens of egrets and herons come back to nest in one of the largest rookeries in the South Bay, smack in the middle of Google’s Mountain View campus on Shorebird Way.

The breeding ground has long been a sanctuary for great egrets, snowy egrets and black-crowned night herons. This year a great blue heron has joined the lively scene, adding to the colorful sights and sounds of birds nesting high in the sycamore trees that line the narrow street.

The rookery is distinct for its size and for its unusual location, said Matthew Dodder, executive director of the Santa Clara Valley Audubon Society.

Egrets and herons usually nest near large bodies of water and not in urban centers. But about 10 years ago, in the midst of its office expansion plans, Google started noticing a large number of birds occupying the trees along Shorebird Way, Dodder said.

It was the height of the breeding season, which typically runs from March until August, and conservationists were worried about the fate of the nestlings. At the urging of the Audubon Society, the city of Mountain View and Google agreed to close off the street to protect the colony during this critical time.

The arrangement continues today; the street is closed to traffic when the chicks hatch and reopens when the breeding season ends, Dodder said. He said it’s an important site, noting that the rookery has about 100 nests and represents more than 20% of the monitored egret population in the South Bay.

May also is a particularly opportune time to see the wildlife, Dodder said. The chicks have hatched and the rookery is now a cacophony of bird calls and responses. The nestlings are making a hissing sound while the adults are gurgling and croaking. “You really have to hear it to believe it. It sounds like an alien creature,” Dodder laughed.

The lone great blue heron that arrived this year was likely attracted by the noise, and then settled down after realizing that the open canopy was suitable for its large size, Dodder said. The blue heron stands about 4 feet tall, making it the largest of the lot.

The other birds also are striking to see, as mature great egrets stand about 3 feet tall and have black feet, while snowy egrets are 2 feet tall and have yellow feet. Both grow long plumes on their backs. The black-crowned night heron is smaller and stockier and marked with black on its back and head, Dodder said.

While a lot of activity is happening in the trees, much is occurring on the ground too, as the birds are constantly building and rebuilding nests. They are picking up sticks around the rookery and sometimes even stealing them from other nests to incorporate in their own, Dodder said.

For these reasons, visitors should be cautious when walking under trees, as sticks and twigs might fall on them. “Whitewashing” also is a hazard, Dodder said, noting that visitors should avoid standing directly under nests and be wary of bird droppings.

When not nesting, the egrets also can be seen by nearby water sources, like the retention basin and Stevens Creek, where they forage for fish and crawdads during the day to bring back to their young. The Black-crowned night heron is a nocturnal species and more active during dusk and dawn.

“It’s a real opportunity to see wildlife in action. And it’s right here in Mountain View,” Dodder said, encouraging the public to come out to the rookery.

Once the breeding season ends, the birds will disperse to other parts of the South Bay and return the following year to start the cycle anew. 

To help the public learn more about egrets and herons, the Audubon Society is holding “office hours” at the rookery on Wednesday, May 29 and Wednesday June 12 from 11 a.m. to 1 p.m. at Shorebird Way. Volunteers will be available to answer questions and offer resources for visitors to use, like telescopes and binoculars.

More information about the rookery also is available on the Santa Clara Valley Audubon Society website.