A guide to Marin’s summer shorebirds
Summer is generally not thought of as the season for shorebirds in the North Bay. While some waterbirds are here abundantly all year round — herons, egrets, mallards and Canada geese — the great majority of our shorebird species head north or inland to nest, leaving our wetlands and mudflats largely depopulated of the long-legged, long-beaked probers and pickers like yellowlegs, willets, godwits, curlews and dowitchers. But “largely depopulated” is very different than “completely barren,” and July presents some special opportunities for shorebird watching: cute babies for our handful of local nesters and early migrants while the autumn songbirds are still months away from arriving.
Let’s start with the few shorebirds that do nest here. Black-necked stilts and American avocets are two common Bay Area shorebirds that share a family lineage indicated by their extremely long legs, long bills and vivid black and white plumage. To these shared elements of appearance, stilts add red color to their legs, while avocets are easily identified by their reddish heads — when in their summer breeding plumage — and by their unique upcurved bills — those of stilts, and most other shorebirds, are straight. Both of these birds are extremely common from fall through spring.
Both stilts and avocets, however, also breed in the North Bay in small numbers. Typically, they look for small islands or other small, safe patches of land in wetlands and marshes where they construct simple nests directly upon the ground. Like other shorebirds, stilts and avocets have precocial young, which can toddle about cutely and clumsily in the shallow water soon after hatching. Local nesting populations are small and somewhat erratic depending on water levels and food availability from year to year, but some sites where these distinctive birds have nested include Shollenberger Park in Petaluma and Rush Creek Open Space Preserve and the Hamilton Wetlands in Novato.
Our most widespread nesting shorebird is the killdeer, a plover named onomatopoeically for the sound of their loud, piercing calls. Plovers also have a distinctive shape, being relatively round and plump, with comparatively short legs and quite short and stubby bills. Killdeer are easily distinguished by the two black bands across their breast. Unlike our other local breeding shorebirds, killdeers do not necessarily nest near water at all, instead seeking out gravelly patches in a wide variety of open habitats, including pastures, agricultural areas, suburban roadsides and even flat gravel rooftops. This makes finding baby killdeers even less predictable, but they do often still forage on wetland edges: I’ve seen them at Hamilton and Novato’s Stafford Lake, for instance.
Another of Marin’s plovers, the diminutive snowy plover, has an even more precarious nesting status and is in fact listed as a threatened species in California. These tiny, sparrow-sized plovers have nested at Point Reyes National Seashore’s Limantour Beach and Abbotts Lagoon, and you may see areas marked off for their protection at these and other coastal beaches. Increased corvid populations and the use of beaches by humans and dogs are among the dangers contributing to their threatened status. A final uncommon breeding shorebird of Marin is the black oystercatcher, which searches for nest sites along the immediate rocky ocean coastline.
By July, however, our first migratory shorebirds are already returning from the north and Great Plains. Least and western sandpipers — known familiarly as “peeps” — godwits, curlews and willets are among the species already making their presence felt in local wetlands, but these and other shorebirds will continue to arrive over the coming months. Many will continue on southward, while a large population of many different species will remain present throughout the winter.
One particularly unique group of passing migrants deserve special attention now: the phalaropes. Ecologically, these birds are highly unusual in practicing “serial polyandry,” in which the more colorful females may mate with multiple different males over the course of the breeding season. Observationally, they perform a unique feeding technique in which they spin in tight little circles in the water to stir up invertebrates from the substrate. And distributionally, phalaropes are passing and unpredictable visitors: Wilson’s phalaropes are mostly likely to be seen moving south in July and August, while red-necked phalaropes continue to appear in September and October. Keep your eyes open!
Jack Gedney’s On the Wing runs every other Monday. He is a co-owner of Wild Birds Unlimited in Novato and author of “The Private Lives of Public Birds.” You can reach him at jack@natureinnovato.com.