A wide variety of shorebirds winter in the San Francisco Bay waters, and in Berkeley in particular. A few, like the whimbrel (a type of curlew), migrate from as far away as the Arctic. Elaine Miller Bond, whose work on local wildlife we have been delighted to publish before, recently spent time photographing shorebirds at the Berkeley and Emeryville tidal zones and mudflats in the company of Rusty Scalf, a teacher and trip leader for the Audubon Society.
According to Scalf, these shorebirds have “high odometer readings.” Yet, for foraging, they rely heavily on the fragile, narrow, often muddy habitat between dry land and water — a zone that is increasingly imperiled by global climate change.
Here, we publish a selection of Miller Bond’s gorgeous photos with extended captions written by her describing the birds and their habits.
Top photograph: Berkeley’s shoreline — with its combination of rich mudflats and rocky coastline — provides a comfortable winter home for 20 types of shorebird, also known as “waders” for their long legs. For some of these birds, San Francisco Bay is a winter destination. Other birds stopover here during longer migrations from the high Arctic, Alaskan mountaintops, or other northern nesting grounds. Roosting (resting) on this rock are four different shorebird species: willets (large, grey), a sanderling (small, white), black turnstones (medium, black), and a black-bellied plover (medium, mottled).
Above: When high tide inundates the mudflats and sandy zones, shorebirds rest on higher ground, like coastal rocks. These sanderlings (small members of the sandpiper family) migrated here from the far Arctic tundra, areas fit for polar bears and Arctic foxes. At low tide, sanderlings rush ahead of incoming waves and chase after outgoing ones, picking up crustaceans and mollusks left at the tide line. They also probe the sand for small worms and other food.
Above: The whimbrel — identified, in part, by its down-curved bill — undertakes one of the longest migrations among shorebirds, from the Arctic to the southern tip of South America. “On any given outing, we’re lucky to see just one whimbrel,” says Rusty Scalf, teacher and trip leader for the Audubon Society. But in this “truly exceptional” year, birdwatchers have spotted as many as 22 whimbrels roosting at high tide in Emeryville, which is both a mystery and a thrill.
Above: Low tide exposes the mudflats, where shorebirds can forage in relative safety. (These soupy silts act like quicksand for predators like coyotes.) In the distance, a long-billed curlew — North America’s largest shorebird — probes the mud for burrowing crabs and shrimp. A flock of least sandpipers — North America’s smallest shorebirds — hunts the same area for smaller prey.
Above: A shorebird’s bill is shaped as a specialized tool for plucking small creatures between coastal rocks, pecking them from the kelp wrack, or probing muds and sands. This willet is considered a “generalist” whose lance-like beak allows it to feed on a variety of worms, insects, and shellfish found all around the aquatic zone. It can even swallow mollusks whole, with the help of its gizzard and hydrochloric acid in its stomach, which, as Scalf jokingly says, “makes shell go off like an Alka-Seltzer.”
Above: Over half of the shorebird species that winter in Berkeley depend on coastal mudflats (or “tidal flats”) and the life that oozes from them. And, since the days of the Gold Rush, these vital habitats have lost much ground. According to a report provided by the San Francisco Estuary Institute, the greater San Francisco Bay has lost 42% of its historic tidal flats, largely due to bay infilling, erosion, and evolution of tidal marshes. Non-native plants growing in mudflats (particularly Spartina alterniflora, a type of cordgrass) and the long-term effects of global warming pose further threats.
Above: This is the mouth of Schoolhouse Creek, a natural stream that feeds coastal mudflats. At its headwaters, the stream collects rainwater from the Berkeley hills. Near the foot of Virginia St. the stream pours out of a culvert, depositing nutrient-rich silt onto the shoreline. And here, among the cool, rippling tides and long-toed prints of shorebirds, life really does rise from the mud.
Above: Whimbrels are members of the curlew family, which earned their scientific name, Numenius, from the “new moon” crescent shape of their bills.
Above: Thousands of marbled godwits spend their winters in San Francisco Bay, having migrated here from their nesting grounds in northern interior prairies. Notice the marbled godwit’s slightly upturned bill.
Above: This willet may look all grey, but it actually boasts flashy black-and-white wings, visible when flapping or flying. Equally bright is the male willet’s springtime call: pill-will-willet. It sounds like he’s calling his name!
Above: The black-bellied plover is a shorebird that does not probe the sand or mud. Instead, it feeds visually, much like a robin, scanning the mudflats for slender worms and other prey that rise to the surface at night.
Above: Sanderlings can roost in large flocks, giving a soft, fleecy look to the shoreline rocks.
Above: During a winter sunset, a willet (large) and two least sandpipers (small) forage together in the mudflats.
Above: Given the proper care, mudflats can thrive near the city.
Checklist for shorebirds in Berkeley:
- Black-bellied Plover (Pluvialis squatarola)
- Semipalmated Plover (Charadrius semipalmatus)
- Killdeer (Charadrius vociferous)
- Black Oystercatcher (Haematopus bachmani)
- American Avocet (Recurvirostra americana)
- Black-necked Stilt (Himantopus mexicanus)
- Greater Yellowlegs (Tringa melanoleuca)
- Willet (Tringa semipalmata)
- Spotted Sandpiper (Actitis macularius)
- Whimbrel (Numenius phaeopus)
- Long-billed Curlew (Numenius americanus)
- Marbled Godwit (Limosa fedoa)
- Ruddy Turnstone (Arenaria interpres)
- Black Turnstone (Arenaria melanocephala)
- Surfbird (Aphriza virgata)
- Sanderling (Calidris alba)
- Dunlin (Calidris alpina)
- Western Sandpiper (Calidris mauri)
- Least Sandpiper (Calidris minutilla)
- Long-billed Dowitcher (Limnodromus scolopaceus)
Where to find mudflats and shorebirds in Berkeley:
- César Chavez Park and the Berkeley Marina Complex
- Aquatic Park (particularly the southern end)
- Mouth of Strawberry Creek (behind the Sea Breeze Market & Deli, 598 University Avenue)
- Mouth of Schoolhouse Creek (near the foot of Virginia Street)
- Dotted along the shoreline between the larger mudflats in Albany and Emeryville
Special thanks to April Robinson at the San Francisco Estuary Institute and Rusty Scalf, who praises the Golden Gate Audubon Society for its support of wetlands.
Elaine Miller Bond is the author/illustrator of “Affimals: Affirmations + Animals” and the upcoming sequel, “Dream Affimals,” from Sunstone Press. She is also the photographer for “The Utah Prairie Dog” (University of Utah Press), projected for publication in 2014.
Sitting on the dock of the bay: birds throng Berkeley pier [02.28.13]
Rare bluebird sightings bring happiness in a Berkeley park [08.07/12]
In Tilden Park’s Jewel Lake: Spotting a rare river otter [04.05.12]
Up close with Berkeley’s wildlife at Tilden Regional Park [03.06.12]
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