Double-crested Cormorants

By Luke Matthews

The Cormorant is a large, fish-eating waterbird and California has three district species: Brandt’s, Double-crested and Pelagic. All three of these species are very similar in size, appearance and unique attributes. But, only the Double-crested Cormorant can be found in the Sacramento Valley. Both the Brandt’s and Pelagic Cormorants are found on the coast and out in the Pacific Ocean.

The Double-crested Cormorant is a large, mostly black bird with a yellow bill and blue eyes. Both sexes look the same and during the breeding season the black feather on adult birds becomes iridescent. Additionally, they develop two tufts of white feathers above their eyes (their crests). These cormorants can be seen throughout the Sacramento Valley year-round in most areas that have regular water and fish. While these birds do not use rice fields specifically, they are regularly seen in and around irrigation infrastructure, such as ditches and sloughs.

The diet of Double-crested Cormorants is made up almost entirely of fish, although they will also eat crayfish, frogs, snakes and many other aquatic vertebrates. These birds swim underwater in pursuit of their prey and primarily use their large, webbed feet for propulsion. Unlike the feathers on most other waterbirds, such as ducks and geese, cormorant feathers are not highly waterproof and get soaked while they are in the water. Due to this, cormorants can often be seen perched on trees, logs or rocks holding their wings open to dry out in the sun. Although it is not completely understood, some researchers believe that allowing their feathers to get saturated with water may actually help them while swimming underwater.

Cormorants are ubiquitous in the Sacramento Valley but are often overlooked as being large, somewhat ugly birds. Nevertheless, the next time you see these birds perched on a rock with their wings held wide, consider how unique the cormorant actually is. These are some of the only birds that can fly, walk on land, swim on the surface and swim underwater! Quite a feat for such a large, clumsy bird.

Luke Matthews is the Wildlife Programs Manager for the California Rice Commission