Cormorants

1. Cormorants corvus marinus - sea crow

2. 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

3. 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

4. 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

5. 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

6. Neotropic Cormorant Phalacrocorax brasilianus

7. Identification • Length: 22 in. • Wingspan: 40 in. • Formerly Olivaceous Cormorant • Dull yellow, pointed gular region with thin pale border Neotropic Cormorant

8. Preferred Breeding Open water wetlands Preferred nesting Low lying trees over water Islands (Telfair, Morrison 1995) Range

9. 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.

10. 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

11. 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

12. 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

13. 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

14. Nesting Cont. • Young • Both parents feed young until 11th week • Independent at 12 weeks • 1 brood per year

15. Status • Population size dropped drastically in Texas until 1960’s • DDT’s • Now • Increased/ing in Texas and Louisiana

16. Red-Faced Cormorant Phalacrocorax urile

17. Identification • Length: 28 in. • Wingspan: 48 in. • blue gular region is bordered in bright red that reaches up onto the forehead

18. 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

19. Breeding Aleutian Island Chain Southeastern Gulf of Alaska Year-round Aleutian Islands Pribilof Islands few sites in Gulf of Alaska and Northern Sound Range

20. Habitat • Ocean, Coast, Islands • Close to shore in cool ocean waters • Rocky bays • Straits between Islands

21. Feeding Behavior • Dives from surface • propelled by feet when swimming • Forages alone • May feed near bottom in rocky areas

22. 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

23. 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

24. 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

25. Nesting Cont. • Young • fed by both parents • Independence estimated at 50-60 days • 1 Brood per year

26. 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

27. Double-Crested Cormorant Phalacrocorax auritus

28. 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

29. Breeding Range

30. Wintering Range, cont.

31. 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

32. 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

33. 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

34. 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

35. 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

36. 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!

37. 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

38. 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

39. 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.