Double-Crested Cormorant
Double-Crested Cormorant
Nannopterum auritum
Quick Identification guide
Quick Identification guide
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Identifiable by its slender, elongated body and long neck, giving it a streamlined appearance
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Features a hooked, slender beak and a distinct orange-yellow gular pouch at the base of the bill
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Typically has double crests of black feathers on its head, more prominent during the breeding season
Description
The Double-Crested Cormorant is a large, black waterbird with a long neck and a hooked beak. It dives underwater to catch fish and often spreads its wings to dry in the sun. During the breeding season, it grows two small feather tufts on its head, which give the bird its name. It lives near lakes, rivers, and coasts across North America.
The double-crested cormorant can weigh between 1200to2500grams and be from70to120centimeters tall.
The Double-crested Cormorant typically lives up to 6 to 10 years in the wild, although some individuals may reach 20 years. Compared to related species, the Great Cormorant can live up to 25 years, while the Brandt's Cormorant has a similar lifespan of around 10 years. Environmental factors, predation, and human activities influence these lifespans. Cormorants generally exhibit varying lifespans based on species and habitat conditions, reflecting adaptability and resilience among these waterbirds.
Did you know?
Most popular questions about double-crested cormorant
How to recognise a double-crested cormorant?
General appearance
The Double-crested Cormorant is a large water bird with a long neck and a distinctive hooked beak. Its plumage is generally dark, with an iridescent blue-black sheen. During breeding season, adults exhibit striking orange skin around the base of the beak and a distinctive pair of white tufted crests.
Male vs female
Males and females are similar in appearance, both having dark plumage and orange facial skin, though males tend to be slightly larger in size. During the breeding season, the white crests are more prominent in both sexes.
Juvenile
Juvenile Double-crested Cormorants have brownish plumage rather than the dark iridescence seen in adults. Their underparts are paler, and they lack the distinctive orange facial skin and crests until they mature. This coloration can make them appear somewhat mottled.
Breeding and nesting habits of the double-crested cormorant
Mating behaviors
Double-crested Cormorants engage in elaborate courtship displays, including head bobbing and wing spreading. Males often present small fish to females as part of the courtship ritual.
Nesting details
These birds typically build nests in colonies near water, often on trees or cliffs. Nests are constructed from sticks, seaweed, and other available materials. They do not nest in gardens, eliminating the need for habitat creation.
Eggs and chick-rearing
Females lay 3-4 eggs per clutch. Both parents incubate the eggs for about 25-28 days. After hatching, chicks are fed regurgitated food by both parents and fledge approximately 5-6 weeks later.
What does a double-crested cormorant like to eat?
Aquatic animals
Small animals
Natural diet
The Double-crested Cormorant primarily feeds on fish, making up the bulk of its diet. It hunts by diving underwater, using its powerful legs to propel itself and its sharp eyes to spot prey. Common fish consumed include perch, catfish, and alewives. Aside from fish, the cormorant may also eat amphibians, crustaceans, and insects, depending on availability.
Bird feeders
Double-crested Cormorants are unlikely to visit bird feeders as their diet is primarily aquatic and they do not rely on seeds or similar food commonly found at feeders. They are more adapted to catching live prey in aquatic environments.
Create a water oasis
Double-crested Cormorants love water, so a small pond or water feature can be a major draw. Make sure it's clean and stocked with small fish to really capture their interest.
Serve up their favorite snacks
These birds aren't typical feeder visitors as they primarily enjoy fish. However, adding small fish or fish-flavored treats near your water feature may encourage a visit. While traditional bird seeds won't usually work, having a supply of Bird Buddy fish treats, specially chosen by experts for the season, could yield the best results.
Provide a comfortable perch
Set up tall poles or dead trees near your water feature where cormorants can perch and dry their wings. This creates an ideal resting spot where they might stay longer.
Add some tall structures
Cormorants like to nest in high places, so consider adding tall, sturdy structures to attract them. These could be artificial platforms or tall trees.
Play the right sounds
While a sing-along might be a bit ambitious, playing recordings of cormorant calls could pique their curiosity and encourage them to check out your yard.
Where can you find double-crested cormorants?
Primary habitat
Double-crested Cormorants prefer coastal areas, lakes, rivers, and reservoirs with abundant fish. They thrive in temperate and subtropical climates.
Additional range
They may also inhabit urban environments and inland water bodies, adapting to unexpected habitats like golf course ponds and city harbors.
Do they migrate?
The Double-crested Cormorant (Phalacrocorax auritus) exhibits both migratory and resident behaviors, depending on its geographic location. Northern populations, particularly those breeding in Canada and the northern United States, typically migrate southward for the winter. Migration generally begins in late August through October, with birds traveling to warmer areas, including the southeastern United States, Gulf Coast, and parts of Mexico. During spring, they return north from February to April for breeding. The migratory routes largely follow major water bodies, leveraging river systems and coastlines for navigation and foraging. Key staging areas often include the Great Lakes, Mississippi River, and coastal regions, providing abundant food resources. Meanwhile, populations in the southern and coastal areas, such as Florida and southern California, are often non-migratory, residing in these milder climates year-round. The adaptability of the Double-crested Cormorant to various habitats, from inland lakes and rivers to coastal bays, helps explain its widespread distribution and varied migratory behavior. These birds can travel in flocks, sometimes forming large groups during migration, which helps conserve energy and enhance navigational efficiency.
What is the role of double-crested cormorants in nature and how to protect them?
Conservation status
The Double-crested Cormorant is generally considered common, with a conservation status of "Least Concern" according to the IUCN Red List. Key conservation efforts focus on habitat protection and monitoring population levels. Significant threats include habitat destruction, human disturbances, and conflicts with fisheries leading to culling in some areas. Efforts to balance conservation and human-economic interests are ongoing, ensuring that populations remain stable while addressing issues related to fishery impacts and wetland preservation.
Ecological role of double-crested cormorants
Its role in the ecosystem
The Double-crested Cormorant, Phalacrocorax auritus, plays a significant ecological role. These birds are excellent fishers, helping maintain balance within aquatic ecosystems by preying on various fish species. This predation pressure can help control populations of invasive or overly abundant fish species that threaten native biodiversity. By consuming large numbers of fish, cormorants contribute to the nutrient cycle, as their waste products fertilize surrounding habitats, promoting plant growth and thereby supporting primary productivity. While primarily piscivorous, these birds also occasionally disperse seeds from consumed fruits, aiding vegetation spread. Additionally, cormorants serve as bio-indicators, their presence indicating healthy, fish-rich waters. They also help control some pest species by feeding on invertebrates and small amphibians, though this is not their primary role. Lastly, their nesting activities enrich soil with organic matter, enhancing the nutrient quality of their environment, which benefits the entire ecosystem.
How to help protect double-crested cormorants
Preservation tips
Enhance wetland habitats
Prioritize the conservation and restoration of wetland habitats crucial for Double-crested Cormorants. Support initiatives that remove invasive species, improve water quality, and restore native vegetation to ensure the health and sustainability of these ecosystems.
Promote sustainable fisheries
Advocate for sustainable fishing practices to maintain fish populations that the cormorants depend on. Work with local agencies to monitor fish stocks and implement limits if necessary to prevent overfishing.
Community science programs
Engage the public through community science projects such as annual bird counts and monitoring programs. Encourage local communities to collect data on cormorant populations and behaviors, aiding conservation efforts with valuable insights.
Education and outreach
Organize workshops and educational programs to raise awareness about the importance of cormorants and the threats they face. Empower communities with knowledge and tools to actively participate in local conservation efforts.