The double-crested cormorant (Phalacrocorax auritus) is a slender black water bird that can be found in both fresh and salt water habitats. These habitats range from the North American coastal waters to the inland lakes and rivers of Middle America. The Bahamas and Mexico are also home to this cormorant species. During winter months, these cormorants will migrate to warmer temperatures and they can often be seen flying together in a v-shaped formation.
When fully grown, this large water bird measures 30-36 inches (75-90 cm) and has a wingspan of about four feet (122 cm). Young double-crested cormorants have white breast feathers that disappear as the bird matures. An orange yellow pouch on the throat and two feathered crests on the head distinguish this cormorant from other cormorant species. These feathered crests, which can be either black or white, are present as the cormorant matures and is ready for breeding.
Adult males and females look similar and they each have a thin bill with a downward facing hook at the tip. They are also almost completely black with a curved neck and a long tail. This long tail acts as a rudder as the double-crested cormorant swims and dives under water. Webbed feet on the cormorant propel it rapidly through the water.
This cormorant swims with only its head above water and it can dive down to 25 feet (762 cm) in search of prey. This bird lacks the oil glands that would normally make its feathers waterproof. Because its feathers absorb water rather than repel it, the cormorant is more capable of diving to greater depths in search of food. Once the bird exits the water, it must stand upright and spread its wings to allow them to dry.
The diet of the double-crested cormorant consists mainly of fish from either fresh water or salt water habitats. It also feeds on shrimp, small amphibians, and invertebrates. When feeding on a large fish, the cormorant will surface with the fish in its beak and position it so that the fish can then be swallowed whole.
Breeding season for the double-crested cormorant is from mid-April to mid-June. The male and female of the breeding pair each gather sticks and twigs to build a nest high up in a tree or on a cliff. Cormorants living in coastal waters may use seaweed to build their nests.
The female cormorant will usually lay three to four blue chalky eggs and these will be incubated in the nest for about a month. Once the eggs hatch, both the male and female cormorant will care for the chicks. The chicks should be ready to leave the nest in 35 to 40 days. Double-crested cormorants are very versatile and have been able to adapt and survive in a variety of habitats.