It took many years of birding before I saw a double-crested cormorant with crests. For years I had seen these birds in various locales—in rafts on the bay, in bodies of freshwater, and further inland, at the Central Valley refuges. I wondered why they weren’t called yellow-throated cormorants, as crests did not seem to be present or obvious. On occasion, I would see some flattened feathers alongside the head that could be crests. And then I visited a breeding colony in Alameda and wow! The crests were standouts, prominent, noteworthy, and extremely obvious. Its scientific name Phalacrocorax auritus translates as bald crow and eared.
Check out a non-breeding bird and then look at one in full breeding plumage and the difference is outstanding. These drab birds suddenly appear otherworldly and incredibly entertaining.
There are 38 cormorant species worldwide and six in North America, and the double-crested are the most numerous and widespread. They are members of the order Pelecaniformes and are fish-eating waterbirds. They are often seen standing with their wings spread out, as if sunbathing, to facilitate drying. Their feathers are not as “water-proofed” as other birds, which allows them to dive deeper with less drag while swimming underwater. They can dive down to 30 feet to catch fish—more than 250 fish species have been reported as prey for the cormorant. These cormorants can stay underwater for 70 seconds, all the while swimming vigorously in pursuit of a meal. Try holding your breath that long, even while you are simply quiet and sitting still in front of your computer.
They are colonial nesters with colonies ranging from a few pairs to over 3,000 pairs. The site I’ve been watching in Alameda has 16 nests. You might be hard put to identify some of the “nests,” as they are little more than a few skinny twigs criss-crossed to form a scanty aerial catch. Of course, this is partially due to the fact that the nest tree has been denuded over the years from the bird’s guano. Eventually the tree will succumb, forcing the cormorants to move on and find another suitable tree.
The excessive whitewash on the tree and surrounding ground is seen as an eyesore by some, and some people find their presence troublesome. One individual was quite expressive in his disdain and took some time to describe the negative impacts on vegetation and the loud noise from the colony. Other passersby said they find the birds exotic, beautiful, and entertaining. One even commented that their presence is an indication of a healthy environment and certainly suggests a thriving fishery.
On average, double-crested cormorants live 10 to 15 years in the wild, although one banded bird lived to a ripe 23 years. They are monogamous, begin breeding between two and five years old, lay an average clutch of three or four eggs, and chicks fledge at five to six weeks old.
Their diet is mostly fish but can include other aquatic prey such as crab, shrimp, amphibians, and sometimes insects. They are born altricial but when they are old enough to stand and move about and the adult returns to the nest, the young chick energetically begs for food. The feeding is a full-throttled, invasive procedure in which the snake-looking young bird sometimes inserts its entire head into the open mouth of the adult, which regurgitates its partially-digested catch.
DCCO is the accepted four-letter abbreviation that birders use to refer to double crested cormorants. These birds are protected under the Migratory Bird Treaty Act (MBTA) and are listed by the International Union of Conservation of Nature (IUCN) Red List as LC or least concern.
These birds with striking aquamarine eyes, long necks, and orange-yellow throat pouches are very common in the Bay Area. Watch for them swimming low in the water in large rafts or singly as they dive and hunt for prey. When onshore observers see a feeding frenzy in the distance, with many blackish birds flying, splashing, and diving, many of these energetic birds are most likely double-crested cormorants.
Rick Lewis is a long-time member of Golden Gate Bird Alliance and other environmental organizations. He contributes often to Bay Area and Central Valley birding groups that promote wildlife and habitat conservation.
This is part of a series of articles coordinated by the Friends of the Alameda Wildlife Reserve (FAWR), a Conservation Committee of Golden Gate Bird Alliance.
