Species Spotlight February 2018

Double-crested Cormorant

Phalacrocorax auritus
The Double-crested Cormorant is gawky, prehistoric-looking bird with a long, dark body and yellowish face. They’re a relative of frigatebirds and boobies, and are the most widespread cormorant in North America, and most often seen in or near water. They’re commonly spotted while perched on docks, rocks and channel markers after fishing, spreading out their wings to dry. Their main activities are fishing and resting (lucky them!), with resting taking up more than half of their day.

Cormorants often travel in V-shaped flocks that shift and fluctuate as the birds alternate bursts of flapping and short glides. They have less preen oil than other birds, so their feathers can get water-soaked, instead of shedding the water, like a duck. This adaptation is thought to help cormorants hunt more effectively underwater.

Before a cormorant takes flight, it tends to stretch its neck in the direction it intends to fly. When it comes in for a landing, a cormorant will puff out the orange skin on its neck, and after landing gives a ritualistic little hop. But, if one lands too close to another, especially when competing over a nest site, the cormorants will face off, stretching their necks and mouths wide open to show the other the bright blue color inside their mouths while hissing and shaking their heads at one another.

Their diet is mostly all fish, with the occasional insect, crustacean or amphibian. They eat a wide variety of fish (reportedly, more than 250 different species!), and have an impressive fishing technique: diving and chasing fish underwater with their powerful webbed feet. In addition, the tip of its upper bill is shaped like a hook, which can help them in catching prey. They can forage by themselves or in groups.

To attract a mate for the season, a male cormorant will choose a site and greet a female by standing confidently to display the crests on his head and bright colors of his neck and his eyes, all the while grunting and waving his outstretched wings at his chosen mate. These birds breed on the coast, and on large inland lakes. They form colonies of stick nests built high in island trees or in patches of flooded logs.

Both the male and female work to build the nest – the male provides most of the materials, and the female constructs the nest. The nest materials consist of sticks and debris, and lined with finer materials. They’ve even been known to incorporate trash or debris items such as rope, balloons, fishing nets and plastic to incorporate into the nest, even parts of dead birds! The nest will be between 1 ½ – 3 feet in diameter and between 4-17 inches high, with ground nests being wider, and tree nests being deeper.

Double-breasted Cormorants usually lay 3-4 eggs, but can lay as many as 7. Incubation is done by both male and female and typically lasts 28-30 days, and both parents will feed their young. After 3-4 weeks, nestlings may wander through the colony but will return to their nest for feeding. They typically start to fly at about 5-6 weeks old, and are mostly independent at 9-10 weeks.

Population numbers for these beautiful birds has had its ups and downs throughout the years. After DDT was banned in 1972, populations were on the rise, and are still increasing and expanding to this day.

Cool Facts: From a distance, Double-crested Cormorants are dark birds, but up close they have some magnificent coloring – orange-yellow skin on their face and throat, compelling aquamarine eyes that sparkle like jewels, and a mouth that is bright blue on the inside.

The double-crest of the Double-crested Cormorant is only visible on adults during breeding season. The crests are white in cormorants from Alaska, and black in other regions.

Photo Credit: https://commons.wikimedia.org/wiki/File:Double-crested_Cormorant_at_Ding_Darling_NWR.jpg