Phalacrocorax auritus
(Double-crested Cormorant)

Order: Pelecaniformes
Order Description: Pelicans, Cormorants
Family: Phalacrocoracidae
Family Description: Cormorants

Physical Description:
Size 30-36" (76-91 cm). Idaho's only breeding cormorant. A goose-sized, black or dark bird. Immature birds light brownish. Breeding adults have inconspicuous tufts on either side of the crownClick word for definition of the head. Head normally uplifted. Distinguished from other cormorants by its orange-yellow throat patch. Cormorants will fly in lines or wedges, similar to geese, but are silent. Neck kinked when in flight.

Similar Species- No other cormorants normally breed in Idaho. Very distinct.

Generally silent.

Breeds throughout much of North America (locally in interior), from southern Alaska, Manitoba, and Newfoundland, south to Gulf Coast and northwestern Mexico. Winters throughout most of coastal breeding range.

Found on lakes, rivers, swamps, and seacoasts. In Idaho, occupies larger water courses and reservoirs.

Feeds primarily on nongame fish.

Dives from water surface to obtain food; usually feeds in water less than 15 m deep. Forages cooperatively. Nests mostly in colonies; entire colony will nest either in tree or on ground. Increased sea surface temperatrues, such as those associated with El Nino events, were correlated with decreases in nesting populations in Washington. Species is common transient and summer breeder in Idaho, where nesting areas are easily disturbed by man. Gulls prey on eggs. Young can suffer from heat prostrationClick word for definition.

Both sexes in turn incubateClick word for definition 2-9 eggs (usually 3-4), for 24-25 days (southeastern Idaho study found average of 3.5 young for 12 nests). Young first fly to water at about 35-42 days, and become independent at 10 wk. Adults usually breed by third year.

Element Code: ABNFD01020
Status: Protected nongame species
Global Rank: G5
State Rank: S2
National Rank: N5B,N5N

Important State References:
Trost, C.H. and A. Gerstell. 1994. Status and distribution of colonial nesting waterbirds in southern Idaho, 1993. Dept. Biol. Sciences, Idaho St. Univ., Pocatello. 101pp.

Photo by George Jameson, ©2002 and Jeff Spendelow,© 1999
Design by Ean Harker©1999, 2000.
Written by Jason Karl, 2000.