Birding and biking through Oakland's Arrowhead Marsh

At this time of year, many birds are migrating through the Bay Area from colder climates, looking for more abundant food. Year-round residents are eating whatever they can to make it through the winter. On our bike ride at Oakland’s Arrowhead Marsh, we observed birds engaged in different kinds of feeding activities. Naturalists Luanne and Jorge explained what we were seeing.

Dabbling: Many aquatic birds are dabblers. Keeping their heads down, they scoop up vegetation and small creatures at the surface of the water. Some well-known dabblers are mallard ducks, greater scaups, and Canada geese.

Drying off: Most aquatic birds have waterproof feathers. The cormorant is a notable exception, with feathers that absorb water, helping them stay submerged while hunting. Cormorants can dive 8-20 feet, and stay under for 30 seconds. When a cormorant finishes hunting, it’s too wet and heavy to fly. Look for cormorants spreading their wings to dry in sunny spots like docks, logs, or exposed trees. 

Sallying: Some birds catch insects in midair. It’s common to see a bird land on a perch, fly off to catch a bug, and then return to the very same perch. This back and forth flying is called sallying. Look for black phoebes sallying from a branch or fencepost, especially in places where bugs are abundant.

Sitting on a snag: a snag is a piece of the landscape that sticks out, like a tree limb, or a dock piling. Most raptors have fantastic eyesight and use snags as a vantage point to survey the area. We observed a red-tailed hawk on a snag before it flew off to hunt. We also saw a turkey vulture use the same snag. Turkey vultures aren’t predators: they’re scavengers that only eat already-decaying carrion. Turkey vultures rely more on their sense of smell than eyesight to find meals, so we suspect the vulture may have been using the snag as a place to rest.