Double Crested Cormorant
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The double-crested cormorant (''Nannopterum auritum'') is a member of the
cormorant Phalacrocoracidae is a family of approximately 40 species of aquatic birds commonly known as cormorants and shags. Several different classifications of the family have been proposed, but in 2021 the IOC adopted a consensus taxonomy of seven ge ...
family of
water bird A water bird, alternatively waterbird or aquatic bird, is a bird that lives on or around water. In some definitions, the term ''water bird'' is especially applied to birds in freshwater ecosystems, although others make no distinction from seabi ...
s. It is found near rivers and lakes, and in coastal areas, and is widely distributed across
North America North America is a continent in the Northern Hemisphere and almost entirely within the Western Hemisphere. It is bordered to the north by the Arctic Ocean, to the east by the Atlantic Ocean, to the southeast by South America and the Car ...
, from the
Aleutian Islands The Aleutian Islands (; ; ale, Unangam Tanangin,”Land of the Aleuts", possibly from Chukchi language, Chukchi ''aliat'', "island"), also called the Aleut Islands or Aleutic Islands and known before 1867 as the Catherine Archipelago, are a cha ...
in
Alaska Alaska ( ; russian: Аляска, Alyaska; ale, Alax̂sxax̂; ; ems, Alas'kaaq; Yup'ik: ''Alaskaq''; tli, Anáaski) is a state located in the Western United States on the northwest extremity of North America. A semi-exclave of the U.S., ...
down to
Florida Florida is a state located in the Southeastern region of the United States. Florida is bordered to the west by the Gulf of Mexico, to the northwest by Alabama, to the north by Georgia, to the east by the Bahamas and Atlantic Ocean, and to ...
and
Mexico Mexico (Spanish: México), officially the United Mexican States, is a country in the southern portion of North America. It is bordered to the north by the United States; to the south and west by the Pacific Ocean; to the southeast by Guatema ...
. Measuring in length, it is entirely black except for a bare patch of orange-yellow facial skin and some extra plumage that it exhibits in the breeding season, when it grows a double crest in which black feathers are mingled with white. Five subspecies are recognized. It mainly eats
fish Fish are aquatic, craniate, gill-bearing animals that lack limbs with digits. Included in this definition are the living hagfish, lampreys, and cartilaginous and bony fish as well as various extinct related groups. Approximately 95% of li ...
and hunts by swimming and diving. Its feathers, like those of all cormorants, are not waterproof and it must spend time drying them out after spending time in the water. Once threatened by the use of
DDT Dichlorodiphenyltrichloroethane, commonly known as DDT, is a colorless, tasteless, and almost odorless crystalline chemical compound, an organochloride. Originally developed as an insecticide, it became infamous for its environmental impacts. ...
, the numbers of this bird have increased markedly in recent years.


Taxonomy

The double-crested cormorant was described by
René Primevère Lesson René (''born again'' or ''reborn'' in French) is a common first name in French-speaking, Spanish-speaking, and German-speaking countries. It derives from the Latin name Renatus. René is the masculine form of the name (Renée being the feminine ...
in 1831. It was formerly classified in the genus ''
Phalacrocorax ''Phalacrocorax'' is a genus of fish-eating birds in the cormorant family Phalacrocoracidae. Members of this genus are also known as the Old World cormorants. Taxonomy The genus ''Phalacrocorax'' was introduced by the French zoologist Mathurin ...
'', but a 2014 study supported reclassifying it and several other American cormorant species into the genus ''
Nannopterum ''Nannopterum'' is a genus of cormorant comprising three species. They are found throughout the Americas, hence the common name American cormorants. These species were formerly classified in the genus '' Phalacrocorax''. A molecular phylogenet ...
''. The
IOC The International Olympic Committee (IOC; french: link=no, Comité international olympique, ''CIO'') is a non-governmental sports organisation based in Lausanne, Switzerland. It is constituted in the form of an association under the Swiss ...
followed this classification in 2021. Its scientific genus name is derived from the
Greek Greek may refer to: Greece Anything of, from, or related to Greece, a country in Southern Europe: *Greeks, an ethnic group. *Greek language, a branch of the Indo-European language family. **Proto-Greek language, the assumed last common ancestor ...
words : ''nános'', "small" and : ''pterón'', "wing". This genus name was originally coined for the
flightless cormorant The flightless cormorant (''Nannopterum harrisi''), also known as the Galapagos cormorant, is a cormorant endemic to the Galapagos Islands, and an example of the highly unusual fauna there. It is unique in that it is the only known cormorant th ...
(''N. harrisi''), which does have very small wings; although the double-crested cormorant has normal-sized wings, it (along with the
neotropic cormorant The neotropic cormorant or olivaceous cormorant (''Nannopterum brasilianum'') is a medium-sized cormorant found throughout the American tropics and subtropics, from the middle Rio Grande and the Gulf and Californian coasts of the United States so ...
, ''N. brasilianum'') was still reclassified into the genus ''Nannopterum'' when the relationship between it and the flightless cormorant became apparent. The species name is from the
Latin Latin (, or , ) is a classical language belonging to the Italic branch of the Indo-European languages. Latin was originally a dialect spoken in the lower Tiber area (then known as Latium) around present-day Rome, but through the power of the ...
', "eared", referring to its nuptial crests. Its common name refers to the same nuptial crests. Five subspecies are recognized: *''N. a. albociliatum'' ( Ridgway 1884), Farallon cormorant, breeds along the
Pacific The Pacific Ocean is the largest and deepest of Earth's five oceanic divisions. It extends from the Arctic Ocean in the north to the Southern Ocean (or, depending on definition, to Antarctica) in the south, and is bounded by the continen ...
coast of North America from
British Columbia British Columbia (commonly abbreviated as BC) is the westernmost province of Canada, situated between the Pacific Ocean and the Rocky Mountains. It has a diverse geography, with rugged landscapes that include rocky coastlines, sandy beaches, ...
to Bird Island in the state of
Sinaloa Sinaloa (), officially the Estado Libre y Soberano de Sinaloa ( en, Free and Sovereign State of Sinaloa), is one of the 31 states which, along with Mexico City, comprise the Administrative divisions of Mexico, Federal Entities of Mexico. It is d ...
,
Mexico Mexico (Spanish: México), officially the United Mexican States, is a country in the southern portion of North America. It is bordered to the north by the United States; to the south and west by the Pacific Ocean; to the southeast by Guatema ...
and possibly even further south. Significant colonies of these birds may also be found further inland including areas around the
Salton Sea The Salton Sea is a shallow, landlocked, highly saline body of water in Riverside and Imperial counties at the southern end of the U.S. state of California. It lies on the San Andreas Fault within the Salton Trough that stretches to the Gulf o ...
. According to currently available information, this subspecies is the third largest among the subspecies of the double-crested cormorant. Historical records indicate that this species was far more abundant in the past, but due to human persecution and development in their breeding range, the population of this subspecies has declined. The largest colony of cormorants in North America consisted of members of this subspecies at San Martin Island,
Baja California Territory Baja California Territory (Territorio de Baja California) was a Mexican territory from 1824 to 1931, that encompassed the Baja California Peninsula of present-day northwestern Mexico. It replaced the Baja California Province (1773–1824) of ...
, Mexico, and was recorded in 1913. Physically, this subspecies is fairly large and has white to partially white nuptial crests. *''N. a. auritum'' (Lesson, 1831), the nominate subspecies, has the largest and most widespread breeding population. It ranges from the
Great Basin The Great Basin is the largest area of contiguous endorheic basin, endorheic watersheds, those with no outlets, in North America. It spans nearly all of Nevada, much of Utah, and portions of California, Idaho, Oregon, Wyoming, and Baja California ...
and
Rocky Mountains The Rocky Mountains, also known as the Rockies, are a major mountain range and the largest mountain system in North America. The Rocky Mountains stretch in straight-line distance from the northernmost part of western Canada, to New Mexico in ...
east into central and eastern North America. This region includes the
Canadian prairies The Canadian Prairies (usually referred to as simply the Prairies in Canada) is a region in Western Canada. It includes the Canadian portion of the Great Plains and the Prairie Provinces, namely Alberta, Saskatchewan, and Manitoba. These provin ...
and the
Great Lakes The Great Lakes, also called the Great Lakes of North America, are a series of large interconnected freshwater lakes in the mid-east region of North America that connect to the Atlantic Ocean via the Saint Lawrence River. There are five lakes ...
. Historically, this subspecies has bred in abundance across most of this region, though there are questions as to whether this bird has always bred in the Great Lakes region. Some evidence indicates that the bird has only begun breeding in the region since the early 20th century while other evidence suggests that it has been breeding in the region much longer. Physically, this subspecies is moderately large and has black nuptial crests. *''N. a. cincinnatum'' ( Brandt 1837), white-crested cormorant, currently this is the most geographically restricted subspecies with the smallest population. It is found along the southern coast of
Alaska Alaska ( ; russian: Аляска, Alyaska; ale, Alax̂sxax̂; ; ems, Alas'kaaq; Yup'ik: ''Alaskaq''; tli, Anáaski) is a state located in the Western United States on the northwest extremity of North America. A semi-exclave of the U.S., ...
and on the
Aleutian Islands The Aleutian Islands (; ; ale, Unangam Tanangin,”Land of the Aleuts", possibly from Chukchi language, Chukchi ''aliat'', "island"), also called the Aleut Islands or Aleutic Islands and known before 1867 as the Catherine Archipelago, are a cha ...
, ranging west from
Kodiak Kodiak may refer to: Places *Kodiak, Alaska, a city located on Kodiak island * Kodiak, Missouri, an unincorporated community *Kodiak Archipelago, in southern Alaska *Kodiak Island, the largest island of the Kodiak archipelago ** Kodiak Launch Com ...
to Chuginidak in the Aleutians. Historically, the range extended west to the
Near Islands The Near Islands or Sasignan Islands ( ale, Sasignan tanangin, russian: Ближние острова) are a group of American islands in the Aleutian Islands in southwestern Alaska, between the Russian Commander Islands to the west and the Rat ...
, but possibly due to nest predation by introduced
fox Foxes are small to medium-sized, omnivorous mammals belonging to several genera of the family Canidae. They have a flattened skull, upright, triangular ears, a pointed, slightly upturned snout, and a long bushy tail (or ''brush''). Twelve sp ...
es, the birds were no longer breeding in the area by the mid-1930s. Physically, this subspecies is the largest and it bears straight, white nuptial crests. *''N. a. floridanum'' (
Audubon The National Audubon Society (Audubon; ) is an American non-profit environmental organization dedicated to conservation of birds and their habitats. Located in the United States and incorporated in 1905, Audubon is one of the oldest of such org ...
1835), Florida cormorant, the smallest of the five subspecies, it is found from southern and central
Texas Texas (, ; Spanish language, Spanish: ''Texas'', ''Tejas'') is a state in the South Central United States, South Central region of the United States. At 268,596 square miles (695,662 km2), and with more than 29.1 million residents in 2 ...
east to the Atlantic and from
North Carolina North Carolina () is a state in the Southeastern region of the United States. The state is the 28th largest and 9th-most populous of the United States. It is bordered by Virginia to the north, the Atlantic Ocean to the east, Georgia and So ...
south to
Florida Florida is a state located in the Southeastern region of the United States. Florida is bordered to the west by the Gulf of Mexico, to the northwest by Alabama, to the north by Georgia, to the east by the Bahamas and Atlantic Ocean, and to ...
. Records indicate that this subspecies was abundant throughout its range before the 20th century, but now is only abundant in Florida. This bird has dark nuptial crests. *''N. a. heuretum'' This subspecies bears straight, white nuptial crests. Physically, it is the smallest. It has bare lores and a greenish gloss on the head and neck. It breeds only in the mangroves surrounding interior lakes of San Salvador in the Bahamas. It may also be resident on other Bahamian islands.


Description

The double-crested cormorant is a large waterbird with a stocky body, long neck, medium-sized tail, webbed feet, and a medium-sized hooked bill. It has a body length of between long, with a wingspan of between . Double-crested cormorants weigh between . Males and females do not display
sexual dimorphism Sexual dimorphism is the condition where the sexes of the same animal and/or plant species exhibit different morphological characteristics, particularly characteristics not directly involved in reproduction. The condition occurs in most ani ...
. This species has dark-colored plumage with bare supra-loreal skin and
gular skin Gular skin (throat skin), in ornithology, is an area of featherless skin on birds that joins the lower mandible of the beak (or ''bill'') to the bird's neck. Other vertebrate taxa may have a comparable anatomical structure that is referred to as e ...
that is yellow or orange. An adult in breeding plumage will be mostly black with the back and
coverts A covert feather or tectrix on a bird is one of a set of feathers, called coverts (or ''tectrices''), which, as the name implies, cover other feathers. The coverts help to smooth airflow over the wings and tail. Ear coverts The ear coverts are s ...
being a dark grayish towards the center. Nuptial crests, for which the species is named, are either white, black or a mix of the two. These are located just above the eyes with the bare skin on the face of a breeding adult being orange. A non-breeding adult will lack the crests and have more yellowish skin around the face. The bill of the adult is dark-colored. The double-crested cormorant is very similar in appearance to the larger
great cormorant The great cormorant (''Phalacrocorax carbo''), known as the black shag in New Zealand and formerly also known as the great black cormorant across the Northern Hemisphere, the black cormorant in Australia, and the large cormorant in India, is a w ...
, which has a more restricted distribution in North America, mainly on the
Canadian maritime provinces The Maritimes, also called the Maritime provinces, is a region of Eastern Canada consisting of three provinces: New Brunswick, Nova Scotia, and Prince Edward Island. The Maritimes had a population of 1,899,324 in 2021, which makes up 5.1% of Ca ...
; it can, however, be separated by having more yellow on the throat and the bill. The
neotropic cormorant The neotropic cormorant or olivaceous cormorant (''Nannopterum brasilianum'') is a medium-sized cormorant found throughout the American tropics and subtropics, from the middle Rio Grande and the Gulf and Californian coasts of the United States so ...
also looks very similar, and the two species can sometimes be found together where their ranges meet. The plumage of juvenile double-crested cormorants is more dark gray or brownish. The underparts of a juvenile are lighter than the back with a pale throat and breast that darkens towards the belly. As a bird ages, its plumage will grow darker. The bill of a juvenile will be mostly orange or yellowish.


Distribution and habitat

A very common and widespread species, it winters anywhere that is ice-free along both coasts, as far north as southern
Alaska Alaska ( ; russian: Аляска, Alyaska; ale, Alax̂sxax̂; ; ems, Alas'kaaq; Yup'ik: ''Alaskaq''; tli, Anáaski) is a state located in the Western United States on the northwest extremity of North America. A semi-exclave of the U.S., ...
(on the west coast) and southern
New England New England is a region comprising six states in the Northeastern United States: Connecticut, Maine, Massachusetts, New Hampshire, Rhode Island, and Vermont. It is bordered by the state of New York to the west and by the Canadian provinces ...
(on the east coast). It can be found as far south as
Mexico Mexico (Spanish: México), officially the United Mexican States, is a country in the southern portion of North America. It is bordered to the north by the United States; to the south and west by the Pacific Ocean; to the southeast by Guatema ...
and the
Bahamas The Bahamas (), officially the Commonwealth of The Bahamas, is an island country within the Lucayan Archipelago of the West Indies in the Atlantic Ocean, North Atlantic. It takes up 97% of the Lucayan Archipelago's land area and is home to ...
. It migrates from the coldest parts of its breeding range, such as eastern
Canada Canada is a country in North America. Its ten provinces and three territories extend from the Atlantic Ocean to the Pacific Ocean and northward into the Arctic Ocean, covering over , making it the world's second-largest country by tot ...
, and has occurred in
Europe Europe is a large peninsula conventionally considered a continent in its own right because of its great physical size and the weight of its history and traditions. Europe is also considered a Continent#Subcontinents, subcontinent of Eurasia ...
as a very rare
vagrant Vagrancy is the condition of homelessness without regular employment or income. Vagrants (also known as bums, vagabonds, rogues, tramps or drifters) usually live in poverty and support themselves by begging, scavenging, petty theft, temporar ...
, for example in Great Britain,
Ireland Ireland ( ; ga, Éire ; Ulster Scots dialect, Ulster-Scots: ) is an island in the Atlantic Ocean, North Atlantic Ocean, in Northwestern Europe, north-western Europe. It is separated from Great Britain to its east by the North Channel (Grea ...
, and the
Azores ) , motto =( en, "Rather die free than subjected in peace") , anthem= ( en, "Anthem of the Azores") , image_map=Locator_map_of_Azores_in_EU.svg , map_alt=Location of the Azores within the European Union , map_caption=Location of the Azores wi ...
. It is resident on
Pacific Coast Pacific coast may be used to reference any coastline that borders the Pacific Ocean. Geography Americas Countries on the western side of the Americas have a Pacific coast as their western or southwestern border, except for Panama, where the Pac ...
from
Aleutian Islands The Aleutian Islands (; ; ale, Unangam Tanangin,”Land of the Aleuts", possibly from Chukchi language, Chukchi ''aliat'', "island"), also called the Aleut Islands or Aleutic Islands and known before 1867 as the Catherine Archipelago, are a cha ...
south to
Nayarit Nayarit (), officially the Free and Sovereign State of Nayarit ( es, Estado Libre y Soberano de Nayarit), is one of the 31 states that, along with Mexico City, comprise the Federal Entities of Mexico. It is divided in 20 municipalities and its ...
, Mexico (but excluding parts of
British Columbia British Columbia (commonly abbreviated as BC) is the westernmost province of Canada, situated between the Pacific Ocean and the Rocky Mountains. It has a diverse geography, with rugged landscapes that include rocky coastlines, sandy beaches, ...
and the
Southern California Bight The Southern California Bight is a 692-kilometer-long (430 mi) stretch of curved coastline that runs along the west coast of the United States and Mexico, from Point Conception in California to Punta Colonet in Baja California, plus the area of t ...
) and inland to the
Colorado River The Colorado River ( es, Río Colorado) is one of the principal rivers (along with the Rio Grande) in the Southwestern United States and northern Mexico. The river drains an expansive, arid drainage basin, watershed that encompasses parts of ...
, resident on Atlantic Coast in
Long Island Long Island is a densely populated island in the southeastern region of the U.S. state of New York (state), New York, part of the New York metropolitan area. With over 8 million people, Long Island is the most populous island in the United Sta ...
and surrounding areas, southern
New England New England is a region comprising six states in the Northeastern United States: Connecticut, Maine, Massachusetts, New Hampshire, Rhode Island, and Vermont. It is bordered by the state of New York to the west and by the Canadian provinces ...
,
Florida Florida is a state located in the Southeastern region of the United States. Florida is bordered to the west by the Gulf of Mexico, to the northwest by Alabama, to the north by Georgia, to the east by the Bahamas and Atlantic Ocean, and to ...
,
Cuba Cuba ( , ), officially the Republic of Cuba ( es, República de Cuba, links=no ), is an island country comprising the island of Cuba, as well as Isla de la Juventud and several minor archipelagos. Cuba is located where the northern Caribbea ...
, and
Yucatán Peninsula The Yucatán Peninsula (, also , ; es, Península de Yucatán ) is a large peninsula in southeastern Mexico and adjacent portions of Belize and Guatemala. The peninsula extends towards the northeast, separating the Gulf of Mexico to the north ...
Its breeding range extends north throughout most of north-central North America, from
Utah Utah ( , ) is a state in the Mountain West subregion of the Western United States. Utah is a landlocked U.S. state bordered to its east by Colorado, to its northeast by Wyoming, to its north by Idaho, to its south by Arizona, and to it ...
north to
Alberta Alberta ( ) is one of the thirteen provinces and territories of Canada. It is part of Western Canada and is one of the three prairie provinces. Alberta is bordered by British Columbia to the west, Saskatchewan to the east, the Northwest Ter ...
east through the Great Lakes states to
Nova Scotia Nova Scotia ( ; ; ) is one of the thirteen provinces and territories of Canada. It is one of the three Maritime provinces and one of the four Atlantic provinces. Nova Scotia is Latin for "New Scotland". Most of the population are native Eng ...
, and south to northern
Massachusetts Massachusetts (Massachusett language, Massachusett: ''Muhsachuweesut assachusett writing systems, məhswatʃəwiːsət'' English: , ), officially the Commonwealth of Massachusetts, is the most populous U.S. state, state in the New England ...
, along with parts of Alaska adjoining
Bristol Bristol () is a city, ceremonial county and unitary authority in England. Situated on the River Avon, it is bordered by the ceremonial counties of Gloucestershire to the north and Somerset to the south. Bristol is the most populous city in ...
and Kuskowim Bays. Its nonbreeding range extends throughout all coastal plains in the US, including the
Atlantic The Atlantic Ocean is the second-largest of the world's five oceans, with an area of about . It covers approximately 20% of Earth's surface and about 29% of its water surface area. It is known to separate the " Old World" of Africa, Europe an ...
and
Gulf Coastal Plain The Gulf Coastal Plain extends around the Gulf of Mexico in the Southern United States and eastern Mexico. This coastal plain reaches from the Florida Panhandle, southwest Georgia, the southern two-thirds of Alabama, over most of Mississippi, wes ...
s south to
Campeche Campeche (; yua, Kaampech ), officially the Free and Sovereign State of Campeche ( es, Estado Libre y Soberano de Campeche), is one of the 31 states which make up the 32 Federal Entities of Mexico. Located in southeast Mexico, it is bordered by ...
, as well as the
Bahamas The Bahamas (), officially the Commonwealth of The Bahamas, is an island country within the Lucayan Archipelago of the West Indies in the Atlantic Ocean, North Atlantic. It takes up 97% of the Lucayan Archipelago's land area and is home to ...
,
Turks and Caicos The Turks and Caicos Islands (abbreviated TCI; and ) are a British Overseas Territory consisting of the larger Caicos Islands and smaller Turks Islands, two groups of tropical islands in the Lucayan Archipelago of the Atlantic Ocean and n ...
, and
Cayman Islands The Cayman Islands () is a self-governing British Overseas Territory—the largest by population in the western Caribbean Sea. The territory comprises the three islands of Grand Cayman, Cayman Brac and Little Cayman, which are located to the ...
, along with all areas previously stated to be resident. On the Pacific Coast, range includes all areas previously mentioned to be resident, along with British Columbia and the Southern California Bight.


Behavior

The double-crested cormorant swims low in the water, often with just its neck and head visible, and dives from the surface. It uses its feet for propulsion and is able to dive to a depth of for 30–70 seconds. After diving, it spends long periods standing with its wings outstretched to allow them to dry, since they are not fully waterproofed. This species flies low over the water, with its bill tilted slightly upward, sometimes leaving the colony in long, single-file lines.


Diet

Food can be found in the sea, freshwater lakes, and rivers. Like all cormorants, the double-crested dives to find its prey. It mainly eats
fish Fish are aquatic, craniate, gill-bearing animals that lack limbs with digits. Included in this definition are the living hagfish, lampreys, and cartilaginous and bony fish as well as various extinct related groups. Approximately 95% of li ...
, but will sometimes also eat
amphibian Amphibians are tetrapod, four-limbed and ectothermic vertebrates of the Class (biology), class Amphibia. All living amphibians belong to the group Lissamphibia. They inhabit a wide variety of habitats, with most species living within terres ...
s and
crustacean Crustaceans (Crustacea, ) form a large, diverse arthropod taxon which includes such animals as decapods, seed shrimp, branchiopods, fish lice, krill, remipedes, isopods, barnacles, copepods, amphipods and mantis shrimp. The crustacean group ...
s. Fish are caught by diving under water. Smaller fish may be eaten while the bird is still beneath the surface but bigger prey is often brought to the surface before it is eaten. Double-crested cormorants are also considered pests to aquaculturists because of their intense predation on fish ponds which can cause thousands of dollars in losses to farmers. Cormorants regurgitate pellets containing undigested parts of their meals such as bones. These pellets can be dissected by biologists in order to discover what the birds ate.


Breeding

Breeding occurs in coastal areas as well as near inland rivers and lakes. They build stick nests in trees, on cliff edges, or on the ground on suitable islands. They are gregarious birds usually found in colonies, often with other aquatic birds, and have a deep, guttural grunt call.


Recovery

The double-crested cormorant's numbers decreased in the 1960s due to the effects of
DDT Dichlorodiphenyltrichloroethane, commonly known as DDT, is a colorless, tasteless, and almost odorless crystalline chemical compound, an organochloride. Originally developed as an insecticide, it became infamous for its environmental impacts. ...
. Colonies have also been persecuted from time to time in areas where they are thought to compete with human fishing. Recently the population of double-crested cormorants has increased. Some studies have concluded that the recovery was allowed by the decrease of contaminants, particularly the discontinued use of DDT. The population may have also increased because of aquaculture ponds in its southern wintering grounds. The ponds favor good over-winter survival and growth. In 1894, Thomas McIlwraith in his book, ''Birds of Ontario'', concludes his section on double-crested cormorants by saying: "When the young are sufficiently grown, they gather into immense flocks in unfrequented sections, and remain until the ice-lid has closed over their food supply, when they go away, not to return till the cover is lifted up in the spring." For populations nesting in the
Great Lakes The Great Lakes, also called the Great Lakes of North America, are a series of large interconnected freshwater lakes in the mid-east region of North America that connect to the Atlantic Ocean via the Saint Lawrence River. There are five lakes ...
region, it is believed that the colonization of the lakes by the non-native alewife (a small
prey fish Forage fish, also called prey fish or bait fish, are small pelagic fish which are preyed on by larger predators for food. Predators include other larger fish, seabirds and marine mammals. Typical ocean forage fish feed near the base of the food ...
) has provided optimal feeding conditions and hence good breeding success. Double-crested cormorants eat other species of fish besides alewives and have been implicated in the decline of some sport-fish populations in the Great Lakes and other areas. Some anglers and commercial fishing outfits believe that double-crested cormorants may be a factor for some populations and in some locations. In light of this belief, and because of calls for action by the public, the
United States Fish and Wildlife Service The United States Fish and Wildlife Service (USFWS or FWS) is an agency within the United States Department of the Interior dedicated to the management of fish, wildlife, and natural habitats. The mission of the agency is "working with othe ...
(the U.S. federal government agency charged with their protection) has recently extended control options to some other government entities. This includes
culling In biology, culling is the process of segregating organisms from a group according to desired or undesired characteristics. In animal breeding, it is the process of removing or segregating animals from a breeding stock based on a specific tr ...
of populations and measures to thwart reproduction, in an effort to control their growing numbers. The U.S. Fish and Wildlife Service retains oversight and the control measures are not extended to the general public (no hunting season). In May 2008, the Canadian government reduced significantly the number of nests of the birds on Middle Island, a small island in
Lake Erie Lake Erie ( "eerie") is the fourth largest lake by surface area of the five Great Lakes in North America and the eleventh-largest globally. It is the southernmost, shallowest, and smallest by volume of the Great Lakes and therefore also has t ...
and part of
Point Pelee Point Pelee National Park (; french: Parc national de la Pointe-Pelée) is a national park in Essex County in southwestern Ontario, Canada where it extends into Lake Erie. The word is French for 'bald'. Point Pelee consists of a peninsula of la ...
National Park. This is an attempt to keep the small island in balance and preserve its vegetation but opponents to the plan have argued that it is based on faulty information, provided in part by anglers who view cormorants as competitors.


Gallery

File:Phalacrocorax auritusZZ.jpg, Mounted skeleton of ''Nannopterum auritum'' at Smithsonian Museum of Natural History File:Double-crested Cormorants Nesting.jpg, Nesting,
Alaska Maritime National Wildlife Refuge The Alaska Maritime National Wildlife Refuge (often shortened to Alaska Maritime or AMNWR) is a United States National Wildlife Refuge comprising 2,400 islands, headlands, rocks, islets, spires and reefs in Alaska, with a total area of , of whic ...
File:Cormorant, Double-crested LOa.jpg, In flight File:Double-crested Cormorant, juvenile.jpg, Juvenile File:Phalacrocorax auritus.jpg, alt=Double-crested cormorant (Phalacrocorax auritus), Ballard (Hiram M. Chittenden) Locks, (Seattle, Washington)
Ballard (Hiram M. Chittenden) Locks
(
Seattle, Washington Seattle ( ) is a port, seaport city on the West Coast of the United States. It is the county seat, seat of King County, Washington, King County, Washington (state), Washington. With a 2020 population of 737,015, it is the largest city in bo ...
).


References


Further reading

*Alsop, Fred J. III; ''Birds of Texas''. Smithsonian Handbooks: DK Publishing, Inc., New York, NY (2002). *
US Fish & Wildlife Service
*McIlwraith, Thomas; ''The Birds of Ontario: Being a Concise Account of Every Species of Bird Known to Have Been Found''. W. Briggs, Toronto, ON (1894) *Wires, Linda A., and Francesca J. Cuthbert; "Historic Populations of the Double-crested Cormorant (Phalacrocorax auritus): Implications for Conservation and Management in the 21st Century" ''Waterbirds'' 29(1): 9–37, 2006.


External links


Double-crested cormorant
– Cornell Lab of Ornithology

– USGS Patuxent Bird Identification InfoCenter * * * {{Taxonbar, from=Q725289
double-crested cormorant The double-crested cormorant (''Nannopterum auritum'') is a member of the cormorant family of water birds. It is found near rivers and lakes, and in coastal areas, and is widely distributed across North America, from the Aleutian Islands in Alas ...
Birds of North America Fauna of the San Francisco Bay Area
double-crested cormorant The double-crested cormorant (''Nannopterum auritum'') is a member of the cormorant family of water birds. It is found near rivers and lakes, and in coastal areas, and is widely distributed across North America, from the Aleutian Islands in Alas ...
Taxa named by René Lesson Extant Pleistocene first appearances Taxobox binomials not recognized by IUCN