Download White Breasted Cormorant Fact Sheet

White-Breasted Cormorant
Phalacrocorax carbo
Description:
• Size:
o Length: 35 in (90 cm)
o Wingspan: 35 in (90 cm)
• Weight: 7.2 lb (3.5 kg)
• Sexual dimorphism: Males are slightly longer and up to 20% heavier than females.
• Physical Description: A large water bird with a long neck and extremely sharp, hooked
bill. Feet are webbed, and tail is fan-shaped. Has a gular pouch immediately below the
beak.
• Coloration: Overall dark gray or black plumage with a bluish or greenish sheen. Upper
mandible is gray, brown, or black, while lower mandible is typically lighter-colored.
Yellow patch of skin at the base of the lower mandible. White on the underparts varies
between individuals, and ranges from a small white patch on the throat to completely
white undersides. During breeding season, a white patch may appear at the thigh.
In the Wild
Habitat and Range:
• Geographic range: A very widespread species, occurring on every continent except
South America and Antarctica.
• Preferred Habitat: Inland waterways such as rivers, reservoirs, and lakes and sea coasts
are the typical habitat for this animal.
Diet:
• Carnivore
o Diet predominantly features fish, but also includes crustaceans, amphibians,
mollusks, and even nesting birds.
Adaptations:
• Unlike many birds, cormorant feathers are designed to allow moisture to penetrate. This
makes the feathers denser, less buoyant, and more adapted to diving. After diving,
however, the cormorant must spend time preening and drying out its feathers.
• Wing morphology is well adapted to flying quickly for short distances. Therefore,
cormorants do not forage over long distances, but instead build their nest adjacent to
their food source. They use their high speed to dive quickly underwater and grab fish, or
other food.
• Possess salt glands that are used to extract salt from any water that they drink.
• The throat, or gular pouch, is also used as a signaling device and as a means for cooling
the body. By panting and fluttering the gular pouch, blood passing through the rich
concentration of capillaries is rapidly cooled.
11/3/2015
White-Breasted Cormorant
The Maryland Zoo in Baltimore
Lifespan:
• Unknown
o The oldest recorded wild cormorant lived to be 22, but 15 years is a more likely
lifespan
Ecosystem relationships:
• Predators: Adults are rarely victims to predation, but eggs and juveniles are eaten by a
wide variety of animals including bald eagles, white-tailed eagles, red foxes, gulls, and
crows.
• Interspecies competitors: May compete with other seabirds including gulls, other
cormorant species, and kittiwakes. However, they frequently form mixed colonies with
these same species for the sake of protection, so the relationship may be mutualistic, or
beneficial to both species.
• Parasites: Commonly play host to parasitic nematodes (parasitic roundworms) and
trematodes (parasitic flatworms).
• Role/ Niche: The cormorant helps control fish populations and distributes nutrients from
the fish on land. They also sometimes serve as prey for larger animals.
Reproduction:
• Breeding season: Varies widely depending upon region and subspecies.
• Behavior: Pairs are seasonally monogamous. Mating season begins with the male
cormorant choosing and defending a nest site, usually on the ground or in a tree. Nests
typically consist of sticks and seaweed lined with grass and feathers. Males attract
females with a wing-waving motion, alternately showing and hiding the white patches
on their thighs with the outstretched wings. Once a pair has been formed, they
reinforce the bond with gargling displays, preening, entwining their necks, and other
reinforcement displays. Once eggs are laid, both parents incubate and feed their young.
Successful mated pairs may return to the same nest site for several years.
• Incubation: 28-31 days
• Clutch size: 3-6 eggs
• Maturation: Chicks are altricial, or helpless, after birth, being both blind and naked.
Develop a coat of down after 6 days. Both parents care for the chicks for about 10 days,
and at least one parent will remain to brood until the chicks are 2 weeks old. At this
point, parents primarily visit the nest to feed and cool the chicks. Feeding is done by
regurgitation, and competition develops among clutches for food. The smallest chick in
a clutch typically dies because it cannot compete for food, but the other chicks
frequently survive. Chicks fledge at 45-55 days, and form crèches, or groups of young, to
defend themselves. Adults continue to feed the chicks for 2-3 months, and are able to
recognize their offspring within the crèches. Sexual maturity is reached at 2-4 years of
age.
Activity:
• Diurnal
o Active during the day
11/3/2015
White-Breasted Cormorant
The Maryland Zoo in Baltimore
•
Social behavior:
o Highly social birds that are typically encountered in groups of 20-200 nesting
birds, though groups of several thousand birds do occur. These animals are only
territorial in the immediate proximity of their nests.
Other “fun facts”:
• The species’ scientific name is Greek. Phalacrocorax translates to “bald raven” and
carbo is “charcoal,” referencing the overall color of the bird.
• Cormorants have historically been trained to catch fish and bring them back to their
handlers, either for sport or food. This typically involves fastening a ring about the neck
of the cormorant to prevent swallowing, but some cormorants are reportedly trained to
bring fish back without the use of an inhibitor. These birds eat only every 8th fish that
they catch, implying the ability to “count.” Cormorants with clipped wings have been
used to drive fish into nets in the Baltic states.
Conservation Status and Threats:
• Listed on the IUCN Red List as Least Concern. The species’ range is so large and their
numbers so high that they cannot be classified under any other category. The most
common threat to these animals is persecution from fishermen who believe that the
cormorants steal or interfere with their catch. Other threats include disturbance of their
habitat and a susceptibility to avian influenza.
• No special listing on CITES.
• Conservation efforts:
o The IUCN suggests that it may be possible to alleviate tension between
fishermen and cormorants by disturbing local cormorants so that they move
elsewhere, or otherwise discouraging nesting in popular fishing areas.
At the Zoo
•
The Zoo houses five white-breasted cormorants
o
o
One male that hatched in 1999
Four birds that hatched in 2008, two males and two females
What We Can Do
•
•
Make environmentally responsible lifestyle decisions to help conserve habitat –
conserve energy and resources, reduce litter and pollution.
Support the conservation efforts of local organizations like The Maryland Zoo as well as
organizations working in the field to protect wildlife and conserve habitat.
References:
• Animal Diversity Web:
http://animaldiversity.ummz.umich.edu/accounts/Phalacrocorax_carbo/
• ARKive: http://www.arkive.org/cormorant/phalacrocorax-carbo/
• IUCN Red List: http://www.iucnredlist.org/details/22696792/0
11/3/2015
White-Breasted Cormorant
The Maryland Zoo in Baltimore