Guest blog post by Kerry Wilcox, Sanctuary Manager, Richardson Bay Audubon Center & Sanctuary

The term waterbird gets used a lot by biologists and naturalists, but it can seem a bit vague and too general. Clearly all birds (let alone life on this planet) depend on water, but even if we just look at the variety of birds that use water for nesting, foraging and resting, the list is pretty impressive.

The North American Waterbird Conservation Plan (2002) lists twenty-three families of birds that are dependent on water bodies for part or all of their life history. They include, among others, the following: loons, grebes, albatrosses, shearwaters, pelicans, cormorants, herons, rails, cranes, gulls & terns, and alcids. These are all easily associated with life on or near the water. Noticeably absent from the list are waterfowl and shorebirds, which have their own specific conservation plans, but this speaks to the sometimes mushy nature of the term waterbird.

Waterbirds at Richardson Bay means birds that use the open San Francisco Bay waters for forage and rest during the winter. Most of the birds are migratory diving ducks such as Greater Scaup, Lesser Scaup, Ruddy Duck and Bufflehead, but we also see large numbers of Double-crested Cormorant, Western Grebe and Clark’s Grebe, American Coot and occasionally Surf Scoter.

From October 1 through March 31 of each winter, the Richardson Bay Audubon Center & Sanctuary closes the approximately 900 acres of San Francisco Bay waters under its management to all boating in order to protect all these visiting birds from disturbance. It is during this time that the Center organizes twice-monthly surveys of the Sanctuary to determine species use of the area. The 2012-13 season will be our seventh year of collecting this data. Numbers of birds in the Sanctuary tend to peak during the annual herring spawn which attracts thousands of fish- and roe-eating ducks, gulls and cormorants. Our latest count, on January 31st, tallied well over 10,000 birds in the Sanctuary alone, and estimates of birds earlier in the spawn were even higher. The period during which the herring spawn is an especially exciting time of year for any birder; it’s a time when you can refine your identification skills and witness a true wildlife spectacle.

With the mandate to protect birds and conserve habitat, Audubon California and the Richardson Bay Audubon Center & Sanctuary are uniquely positioned to provide an eye on the bay and to advocate for changes in human behavior and legislation that can help these amazing wild creatures survive for future generations. Only by knowing how the birds are using the bay now, can we determine if future use has changed for the better or for the worse!

To learn more about Richardson Bay Audubon Center & Sanctuary's work with San Francisco Bay's waterbirds, click here.