Double-crested Cormorant
The Double-crested Cormorant (Nannopterum auritum) is a curious creature. Often confused with ducks, Anhingas, small geese, and loons, these large awkward waterbirds are year-round residents of Florida. Naturally, I see a lot of them in and around the Florida Everglades and wetlands during my bird watching escapades. At a distance Double-crested Cormorants appear pretty unremarkable and opaque, but as they say, don’t judge a book by its cover! A closer look reveals their colorful features, including beautiful turquoise eyes that glimmer like diamonds in the sunlight and bright blue mouths when they open their beaks. Mother Nature never ceases to amaze us, does she?
If anything, one could make the case that the Double-crested Cormorant is more remarkable than other common wetland birds, standing out largely because of their spirited fishing capabilities and unique wing spreading displays. These aviators get their name from the two white or black stripes they dawn on their crowns during breeding season, giving them their distinctive “double crest”. Now, if you know anything about my bird blogs, then you know I simply couldn’t pass up the opportunity to dive into the Double-crested Cormorant—pun 100% intended.
Some Basic Information About the Double-crested Cormorant
- Scientific Name: Nannopterum auritum
- Order: Suliformes
- Family: Phalacrocoracidae (cormorants)
- Conservation Status: Stable; Low concern
- Size & Wingspan: Approximately 27 inches tall; 50-inch wingspan
- Lifespan: 6 to 22 years
Identification
Double-crested Cormorants are the most widespread Cormorant in their family, commonly found perched vertically near salt or freshwater while their waterlogged wing feathers dry. Similarly to Anhingas, they have an undeniable prehistoric look about them, like they could be a species right out of Jurassic Park. Their large bodies are almost entirely veiled in matte blackish-brown plumage; their heads are particularly small—attached to a slender, curled neck. Double-crested Cormorant faces are an apricot orangey-yellow color, as are their chins and lores. Their mouths are a vibrant blue on the inside, joined to a slim bill that’s roughly the size of their heads, with a distinctive hook shape you can’t miss. During breeding and nesting season, their eyes are the most stunning shade of bright teal. Their legs are short and black, fastened to black webbed feet, an adaptation that makes it easier for them to navigate the water. And if there’s one thing this waterbird excels at, it’s swimming.
A Double-crested Cormorant’s feathers aren’t waterproof like duck feathers, which helps them tremendously when searching for food. The fact that their feathers absorb water, means they can more easily sink and dive to catch prey. When swimming, like the Anhinga, they can be seen with their small heads and kinked necks floating low above the surface, their feet propelling them along. In flight, they hover over the water with slow, arduous wingbeats, beak pointed slightly up, belly hanging low, often leaving their rookeries in an organized, single-file-line. In flocks, they tend to fly in a disorderly ‘V’ formation, alternating between laborious flaps and short strides.
As for their exact size, the Double-crested Cormorant measures at about 27 inches tall with a wingspan of around 50 inches—that’s just over four feet! That’s larger than a Snowy Egret, but smaller than a Wood Stork or Great Blue Heron.
Breeding Plumage of the Double-crested Cormorant
During mating season, an adult Double-crested Cormorant dawns modest tufts of breeding feathers on the sides of their heads that can be tough to see at a distance. Their eyes go from pale aquamarine to bright aquamarine and their signature double crest markings become visible on their head. Depending on where they’re located in North America, some Double-crested Cormorants get white stripes, others get black. Typically, the ones found in South Florida have black crests, as opposed to those found in Alaska that have white.
Juvenile Double-crested Cormorant Plumage
Young Double-crested Cormorants are large like their adult counterparts and share many of the same features. They both have a slender hooked beak and orange facial skin, however, rather than dark blackish-brown necks and breasts, juveniles are a lighter cream color in those areas and generally more brown than black throughout the rest of their plumage.
Double-crested Cormorant Calls
The Double-crusted Cormorant is a certainly a social bird, but they don’t typically make a whole lot of noise. The sounds they do make are low, belly growls, almost like a pig when it oinks. They’re generally made when flying from their perch, landing, warding off intruders, and courting a mate.
Habitat
As I touched upon in my opening, the Double-crested Cormorant is yet another bird that’s native to Florida. I’ve got to say that one of the favorite things about living here is that there are so many different species that also call this state home. I’m incredibly fortunate to be just a hop, skip, and a jump away from some of the most miraculous creatures in the world.
Being the most widely distributed cormorant in their feathered family, the Double-crested Cormorant touches every state in the United States at some point, depending on the season. Their reach extends beyond the states to North America as a whole, also inhabiting parts of Canada and Mexico during periods of migration and mating.
These gregarious water fiends are highly adaptable to their surroundings and are the only cormorant to regularly travel inland to freshwater habitats. They are most commonly seen around the coast, lakes, rivers, mangroves, Cypress swamps, ponds, reservoirs, bays, and lagoons.
Where Can I See a Double-crested Cormorant in Florida?
Everywhere! Double-crested Cormorants can be spotted easily all year long in Florida, as long as you know what you’re looking for. Head to the Florida Everglades for a day trip or to Lake Okeechobee and bring your binoculars. Pay attention to the coastlines for a black bird, perched upright with a crooked ‘S’ shaped neck and stubby legs.
You may also see them with their wings spread soaking up the sun to dry their soggy feathers after a dive or sitting low on the water with their heads and beaks upright. Finally, look up and see if you can spot a flock of sloppily flying birds, the chances are good that they’re Double-crested Cormorants.
Behavior and Feeding
Supreme fishers, Double-crested Cormorants excel at swimming and diving. Before taking off, they usually extend their necks in the direction they aim to fly. When landing, they poof out their orange necks and do a little touchdown bounce. To move through the water, they use their feet—and sometimes their wings—as propellors. They methodically float close to the surface of water, often with just their heads poking out and body submerged, then quickly lunge toward prey beneath. Once they’ve captured a fish in their beak, they begin to swallow it whole, stopping periodically to reposition it for easier movement down their throat. They’ve also been known to smack their prey on the water, like crabs for example. When trying to eat this crustacean, hitting them on the surface helps to remove their legs for more effortless ingestion.
Interestingly, Double-crested Cormorants lack the developed preen oil gland that gives most waterbirds their buoyancy, but it’s not a handicap. In fact, it actually gives them an upper hand when swimming underwater and diving because they can sink more efficiently than their peers. The only real downside is having to repeatedly dry their feathers after a dip.
Post-dive, Double-crested Cormorants perch on rocks, branches, and docks fanning their flight feathers using a technique known as ‘wing-spreading’. They tilt their heads toward the sky, striking a pose that looks like a salute to the sun.
Double-crested Cormorants are gregarious and often forage in small and large groups with other wetland birds, sometimes in the thousands. That said, it’s not uncommon to see them fishing alone either, these birds adapt to whatever situation they find themselves in.
Are Double-crested Cormorants Territorial?
Even though these waterbirds are exceptionally social in terms of crowds, they’re also territorial when they need to be. In the event that another Double-crested Cormorant invades his or her space, they face-off with the intruder by stretching their neck, and shaking their head while simultaneously opening their blue mouths and hissing at one another. The first to back down loses the duel. En garde!
What Do Double-crested Cormorants Eat?
Double-crested Cormorants share the same carnivorous diet of most waterbirds—a heavy intake of fish (about a pound a day), shrimp, mollusks, clams, crayfish, frogs, small eels, lizards, salamanders, prawns, snakes, aquatic insects, and even some foliage.
Nesting and Displays
In Florida, breeding season for Double-crested Cormorants begins in April and continues through August. They’re monogamous, so once a male and female have met, they’ll continue to mate together for life. Rookeries are perpetually bustling, as they tend to nest in colonies of 3,000 pairs—or more—and often with several different bird species. Talk about a full house!
Double-crested Cormorant Nests
Nests belonging to the Double-crested Cormorant can be found on the ground, on cliffs near water, or up in trees and measure at around 4 to 17 inches in height and 1.5 feet. to 3 feet in diameter—depending on their location. Elevated nests are usually deeper, but nests on the ground tend to be wider. Additionally, their colonies start inward and gradually flow outward.
As for nesting materials, these waders aren’t picky. The base is made from thick twigs, foliage, seaweed, garbage, and even parts from dead birds, while the insides are padded with grass and any other fine material they find. Also, it’s not uncommon for Double-crested Cormorants to steal nesting materials from other nests that are left unguarded.
And here’s another fun fact for you! Because cormorant rookeries are so heavily populated, there’s often a build-up of fecal matter underneath the nests that can actually kill the tree they’re living in. This doesn’t faze the Double-crested Cormorant though, they just move their nesting area to the ground or another tree close by.
Nesting and Courting Displays
The male cormorant finds the perfect spot for his new home and then the advertising begins! First, he crouches, standing chest down, tail and beak up to ensure he can adequately show-off his nuptial crests, apricot neck, and bright teal eyes. He then breaks into shows of wing waving and low belly calls that sound like little grunts.
When a female has noticed all his effort, he gives her a big “how do you do?” with his mouth open wide to boast its brilliant blue color. Displays aren’t exclusive to the nest site, either. Male Double-crested Cormorants also woo potential mates in the water. They swim back and forth, splash, dive, and bring up plant matter as “gifts” for the lucky lady.
Once the pair forms, the female does most of the nest construction herself, with materials gathered by the male.
Eggs and Parenting
Both the male and female Double-crested Cormorant help with taking care of their younglings. On average mom lays one to seven eggs a brood, which can happen up to two times a season. The eggs are a light shade of blue and have no visible markings. They’re about the size on a jumbo chicken egg, measuring at between 2.2 inches and 2.8 inches long and about 1.5 inches wide. Both parents incubate the eggs for a period of 25 to 28 days until the hatchlings start breaking out of their shells.
Another fun fact? Sometimes you’ll find a stray rock or two in a Double-crested Cormorant nest, likely brought in from their ventures gathering building materials. What’s cute is that they don’t toss it out, rather they treat it like it’s one of their eggs.
Both mom and dad help feed their nestlings by regurgitation in which they press on the adult’s neck, almost like a vending machine dispensing a cup of coffee. Parents also keep their babies hydrated by bringing them water to the nest in their beaks and dumping it into their mouths.
Double-crested Cormorant Maturation
Nestlings start to venture out of the nest around three to four weeks after birth. In breeding rookeries where nests are on the ground, young Double-crested Cormorants will gather with other juveniles, coming back home when it’s feeding time. At about six weeks old, they’re able to fly and dive. At 10 weeks, they’re completely independent of mom and dad. In about two to three years, they’ll start breeding and making a family of their own.
Life Cycle
The Double-crested Cormorant has quite the range when it comes to lifespan, living anywhere from six to 22 years old. The average tends to land closer to six years old, especially in the wild.
There are several predators that the Double-crested Cormorant needs to be leery of in the wild, including but not limited to raccoons, alligators, foxes, crows, gulls, coyotes, blue jays, and grackles—they all prey on the eggs, chicks, juveniles, or even adult Double-crested Cormorants.
Population Trends Over the Years
Over the years, Double-crested Cormorant populations have seen their share of ebbs and flows. In the 1920s, numbers declined mostly at the hands of hunters. The 1950s, began a steady uptick in their population, but by the 1960s agricultural pesticides had started to impact colonies all over the U.S. It wasn’t until 1972 when the use of Dichlorodiphenyltrichloroethane (DDT)—say that three times fast—was banned that Double-crested Cormorants started to thrive again. Flash forward to 2022, there’s an estimated two million of them living in North America.
Double-crested Cormorant & Wildlife Photography
By now, it’s no secret how passionate I am about capturing Mother Nature in her rawest form. Taking pictures of animals not only engages my creative mind, but it also presents unique challenges like being able to get the perfect shot at the perfect moment or being able to predict what’s going to happen based on my previous experiences. For me, it’s calming and invigorating at the same time. And even on the rare occasion I don’t shoot an image, I’m always grateful for the experience and opportunity to connect and be one with my surroundings in that moment. My adventures never fail to leave me with great stories and information that I’m honored to be able to share with you here.
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