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Cormorants. corvus marinus - sea crow. Systematics. Order - Pelecaniformes Suborder - Pelecani Family - Phalacrocoracidae Subfamilies Phalacrocoracinae - Cormorants robust bills stocky bodies breed in colonies near lakes or rivers Leucocarboninae - Shags
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Cormorants corvus marinus - sea crow
Systematics • Order - Pelecaniformes • Suborder - Pelecani • Family - Phalacrocoracidae • Subfamilies • Phalacrocoracinae - Cormorants • robust bills • stocky bodies • breed in colonies near lakes or rivers • Leucocarboninae - Shags • longer, slender bills, heads and bodies • never far from marine habitats and rocky shores
General Characteristics • Large, blackish water birds • long, hooked bill • long tail and long, thin neck • colorful gular pouches and face skin • usually have green eyes • sexes alike • Common sight: Wings stretched to dry them while standing erect
General Characteristics cont. • Swim low in the water - like loons, but with bill tilted up at an angle • Eyes adapted for water as well as air • Flocks fly in lines or wedges - like geese • Silent, except for low grunts occasionally in nesting colonies. • Food - fish, crustaceans • Range - Nearly cosmopolitan
General Characteristics cont. • Number of species • Worldwide - 39 • North America - 6 • Great Cormorant • Double-crested Cormorant • Neotropic Cormorant • Brandt’s Cormorant • Pelagic Cormorant • Red-faced Cormorant
Neotropic Cormorant Phalacrocorax brasilianus
Identification • Length: 22 in. • Wingspan: 40 in. • Formerly Olivaceous Cormorant • Dull yellow, pointed gular region with thin pale border Neotropic Cormorant
Preferred Breeding Open water wetlands Preferred nesting Low lying trees over water Islands (Telfair, Morrison 1995) Range
Breeding: Subantarctic coast of Cape Horn to Southwestern U.S. – Texas, Louisiana, and New Mexico. Postbreeding: Continental U.S. – North to Minnesota, west to California, and east to Mississippi. Range, cont.
Habitat • Tidal waters, lakes • In U.S. • Warm southern waters • fresh • brackish • Coastal regions • protected estuaries, rivers, ponds • Coastal Islands • Tolerant of all but the most disruptive human activities
Feeding Behavior • Dives from surface; rarely from air • Propelled mainly by feet when swimming • May forage in groups • work together to drive fish into shallows
Nesting • Colony Breeders • Mating displays of males • sitting with tail raised • bill pointed up • raising and lowering tips of folded wings • Both sexes display • stretching neck up • bill open • waving head back and forth
Nesting Cont. • Nest • site - live or dead bushes or trees • 3 to 25 feet above water • sometimes on ground on islands • males begin nest, females finish • Eggs • 3-4 - bluish white, become nest stained • Incubation by both sexes - 25 days
Nesting Cont. • Young • Both parents feed young until 11th week • Independent at 12 weeks • 1 brood per year
Status • Population size dropped drastically in Texas until 1960’s • DDT’s • Now • Increased/ing in Texas and Louisiana
Red-Faced Cormorant Phalacrocorax urile
Identification • Length: 28 in. • Wingspan: 48 in. • blue gular region is bordered in bright red that reaches up onto the forehead
I.D. cont. • Similar to the Pelagic Cormorant • the two are often confused when seen together • Shy habits and inaccessible colony sites • least known and least studied of North Pacific • Exclusively marine • ventures onto land only to breed or roost
Breeding Aleutian Island Chain Southeastern Gulf of Alaska Year-round Aleutian Islands Pribilof Islands few sites in Gulf of Alaska and Northern Sound Range
Habitat • Ocean, Coast, Islands • Close to shore in cool ocean waters • Rocky bays • Straits between Islands
Feeding Behavior • Dives from surface • propelled by feet when swimming • Forages alone • May feed near bottom in rocky areas
Nesting • Mixed colony breeder • Often with Pelagic Cormorant • contributes to limited understanding of Red-faced’s natural history and ecology • Less gregarious and social of all Cormorants • Colonies - small and dispersed • few are large, but they are remote from human contact
Nesting Cont. • Male mating display • perches with head over back • bill pointed up • moving head up and down • quickly raising and lowering tips of folded wings - white patches on flanks rapidly covered and exposed
Nesting Cont. • Nest • Site - on ledge (wide or narrow) of cliff or steep slope above water • Mound of grass, seaweed, moss, debris • Nest may be reused • Eggs • 3 to 4 - bluish white • Incubation by both sexes - 31-34 days
Nesting Cont. • Young • fed by both parents • Independence estimated at 50-60 days • 1 Brood per year
Status • Aleutian populations may have been increasing for several decades. • Has expanded range east along southern coast of Alaska • Becoming common east to Prince William Sound
Double-Crested Cormorant Phalacrocorax auritus
Identification • Length: 27 in. • Wingspan: 50 in. • Gular area squared off and orange • extends straight down across throat • Orange lores • Rarely appears crested in the field • Most generally distributed - only one likely to be seen inland in most areas
Breeding Range
Wintering Range, cont.
Habitat • Coasts, bays, lakes, rivers • Very adaptable • may be found in almost any aquatic habitat • Rocky northern coast to mangrove swamps • Large reservoirs to small inland ponds • Nest in trees near or over water, on sea cliffs, or on island ground
Feeding Behavior • Dives from surface, not air • Propelled by feet when swimming • May also use wings! • Forage in groups or alone • Clear or Muddy Water • Near surface rather than near bottom
Nesting • Usually breeds only after first three years • Colony Nester • Male displays on water • splashes wings • swims in zigzags • diving and bringing up pieces of weeds • Nest site displays by males • crouching and vibrating wings while calling
Nesting Cont. • Nest • site near water on cliff edge • island ground • any height in a tree • Eggs • 3 to 4 - Bluish white, becomes nest stained • Incubation by both sexes; 25 - 33 days
Nesting Cont. • Young • Both parents feed young • Start to wander within colony after 3 to 4 weeks, but return to nest to feed • first flight - 5 to 6 weeks • Independence - 9 to 10 weeks
Status • Like Neotropic Cormorant • Numbers dropped through 1960’s • DDT’s • 1972 - Migratory Bird Treaty Act • Populations began increasing • Range is being expanded • Pest in some regions!
Management Concerns • Double-crested Cormorant • Increase in Population causing problems in some regions • Ban of DDT’s and other pesticides • MBTA - 1972 • Changes in fish communities in breed- ing range • aquiculture • additional breeding habitat
Management Concerns Cont. • Options • All lethal take requires permission from USFWS • Depredation Permits • No permits required for non-lethal harrassment • stun guns • scare divices • nets
Works Cited • Causey, Douglas 2002. Red-faced Cormorant. The Birds of North America 617: 1-16. • Glahn, James F. et al. 2000. A Science-Based Initiative to Manage Double-Crested Cormorant Damage to Southern Aquaculture. USDA and NWRC. • Gough, G.A., Sauer, J.R., Iliff, M. Patuxent Bird Identification Infocenter. 1998. Version 97.1. Patuxent Wildlife Research Center, Laurel, MD. http://www.mbr- pwrc.usgs.gov/Infocenter/infocenter.html • Peterson Multimedia Guides: North American Birds. 2002. The Ultimate Birder Disc 1 • Telfair, R.C. and M.L. Morrison 1995. Neotropic Cormorant. The Birds of North America 137: 1-22. • Wires, L.R. et al. 2000. The Double-Crested Cormorant in Eastern and Central North America: A Summary of Status and Selected Research 4: 1-5.