Getting close to our winter guests

By Paul Belz

A group of about thirty curious birders stood at the edge of Lake Merritt, mere feet away from dozens of water birds. “This is the great thing about Lake Merritt,” said Marissa Ortega-Welch, coordinator for the Golden Gate Audubon Society’s Ecological Education Program. We didn’t even need binoculars to see the intricate black and white patterns on the backs of the scaups paddling near our feet.

Scaup on left, close-up of black and white pattern on its back on the right. Photos: Constance Taylor

Scaup on left, close-up of black and white pattern on its back on the right. Photos: Constance Taylor

 

Eared grebes and American coots swam quietly then abruptly dove beak first towards the water’s depths. Egrets and a great blue heron waded on long stick-like legs, and held their slender necks still as they watched the water for passing meals. White pelicans rested on nearby islands while double-crested cormorants sat on buoys, spreading their wings to dry them. Some of these birds live here year round but many are only here during the winter, using Lake Merritt as a rest stop during their migration along the Pacific Flyway

Lake Merritt is an estuary, a former salt marsh wetland that still connects to the San Francisco Bay. It’s influenced by the tides, but a flood gate at 7th Street opens and closes to control the water level. Fresh water from many of Oakland’s streams floats on top of the Bay’s denser salt water, making the water brackish (a combination of fresh and salt water). Mayor Samuel Merritt worked hard to have the Lake proclaimed the nation’s first wildlife refuge in the 1880s, but the legislation may have been less about protecting wildlife and more about protecting humans. The legend goes that Mayor Merritt, who had a house by the Lake, pushed through the no-hunting laws after a bullet shattered his bedroom window! Regardless of why the legislation was passed, ornithologists have since been able to take advantage of this policy to band birds and study their migration routes. For many years, Lake Merritt was the site of the largest bird banding operation on the Pacific Flyway.

“This is my down and dirty method for learning how to identify the Lake’s birds,” Marissa said as she held up a printed silhouettes of bird bodies. She cautioned against using color as the most important clue in identifying ducks and other species, since males and females of the same species can be very different colors. Males are often brightly colored to attract females during mating season, while the drabber females are camouflaged so they can sit on nests without being spotted by predators. Marissa pointed out that the shape of the head, beak, feet, and body are a stronger indication of the species. The observer should notice the animal’s size next; color and patterns can be useful at this point. Marissa said that a bird’s behavior was important, and she recommended the use range maps (found in most field guides) to confirm that a particular bird would likely be in an area.

Cormorant, duck, grebe, egret/heron, gull (photos: 123rf.com, naturemappingfoundation.org, gograph,com, johnrakestraw.net)

Cormorant, duck, grebe, egret/heron, gull (photos: 123rf.com, naturemappingfoundation.org, gograph,com, johnrakestraw.net)

 

Lobed feet of a coot. Photo: Constance Taylor

Lobed feet of a coot. Photo: Constance Taylor

“There’s one bird here that might fool you with its shape,” Marissa said. The body of an American coot resembles that of a duck, but a close look at their white, pincer-like beaks and their long-toed feet shows that they are members of the rail family. These black birds dive to the Lake’s bottom to grab plants, while ducks often use their flatter beaks to strain the water and filter out their food. Coots’ feet aren’t webbed- their long, lobed toes make them good swimmers and help them walk on mud, where ducks might get stuck.

Canvasbacks swam among the crowd of scaups and coots. Canvasbacks have bills that connect to their heads like slides, and their reddish heads and white backs also make them stand out. “Some people say their backs look like a blank, white canvas,” Marissa said, “but I’ve heard that when hunters went out to get ducks, they’d bring a canvas sack with them to carry back the dead birds. They were told to ‘bring the canvas back’… full of ducks, that is!”

Canvasback swimming with the American coots. Photo: Constance Taylor

Canvasback swimming with the American coots. Photo: Constance Taylor

 

Grebes make up another family of bird that visits Lake Merritt during the winter. Up to 5 species have been spotted on the water at once- the small eared grebe, horned grebe, Western grebe, Clark’s grebe, and pied-billed grebe.

Some birders call grebes “hell divers” since they abruptly slide head first into the water to catch food, and vanish for long minutes. Grebes can be recognized by their broad beaks and relatively long necks. These birds have legs that are positioned so far back on their bodies that they can’t easily walk on land! However, the position of their legs makes them excellent divers and swimmers. They build floating nests to lay eggs and raise their chicks, and spend most of their life on the water. They don’t breed at Lake Merritt, so you probably won’t see a floating nest there… but let us know if you do!

Western and Clark’s grebes are famous for the synchronized dancing of males and females when they prepare to mate. They run across the water together, and bow their heads in a graceful greeting. Marissa mentioned that while these birds sometimes mate in other parts of the Bay Area, they usually wait until they’ve left for their northern range in March or April. Grebes who dance on Lake Merritt are probably practicing their moves for the real thing later on. Click here to see the dance! 

Great and snowy egrets sometimes confuse birders who rely mostly on size. Both species’ bodies are covered with bright white feathers, and both wade on long legs whose similarity to sticks may confuse fish. They stand quietly, and quickly snap snake-like necks forward to grab their prey in long beaks.

Marissa commented that most birds reach their lifelong sizes when they leave their nests; ducks and geese are one exception. Small snowy egrets are not baby great egrets. Snowies grow feather tufts on the backs of their heads, distinguishing it from the great egret’s smoother head. The snowies’ yellow feet and black beaks distinguish them from the larger great egrets, with their black feet and yellow beaks. “Spanish settlers called snowy egrets ‘golden foot’,” Marissa said. “That’s a beautiful name.”

Hank the white pelican lives at Lake Merritt year round because his injured wing prevents him from migrating. We saw him resting on one of the Lake’s islands, along with other white pelicans who join him for part of the year. These huge birds resemble brown pelicans, except for their larger size and white feathers. They swim together, gathering and driving fish in front of them until they dive and catch their prey. This behavior is very different from brown pelicans’, which fly above schools of fish and plunge downward, making big splashes.

Humans built the islands to give birds sheltered places where they can nest and find some peace and quiet. A raptor that Marissa said was probably a red shouldered hawk perched on a tree trunk. A green heron hid in the shadows at an island’s edge while a belted kingfisher sat in another tree. Blue billed ruddy ducks, whose upward pointing tails resemble Dennis the Menace’s distinctive cowlick, joined the throngs of swimming birds. Marissa proved that Lake Merritt is a great place for Oaklanders who want to get to know our water birds. It’s a spot where our world and theirs connect!

For a downloadable PDF of a basic guide to the birds at Lake Merritt, Grow Your Oakland has a great one here.

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