From Opus

Photo by Michael Woodruff
Brownsville Sanitary Landfill, South Texas, USA, April 2004

Larus atricilla

Identification

L. 36-41 cm
W. 98-110 cm
One of two North American dark-backed hooded gulls.
Field marks include dark almost slate colored back, small white primary tips, large bill, narrow eye-arcs, and extensive hood (in breeding plumage).
Nonbreeding has limited remnants of hood and black bill.
Juveniles have totally black primary tips, gray neck, and black bill.

Similar species

Bonaparte's Gull is smaller with much lighter gray back, smaller black bill (in all plumages), and with almost no white on primary tips.
Black-headed Gull is slightly larger with much lighter gray back, less extensive hood, and with mostly no white to primary tips.
Franklin's Gull is a slightly smaller dark-backed hooded gull with larger white primary tips (even in juvenal plumage), much less extensive black in wingtips when flying, broader eye-arcs, and smaller thinner bill. Juvenile Franklin's have whitish neck (instead of gray).

Distribution

Nonbreeding plumage
Photo by bobsofpa
Fort DeSoto Park, Florida, USA, September 2008

Year-round resident on eastern and southern coastline of the U.S. from Maine to the southern tip of Texas.
Winters in Mexico.
Rare away from east coast and south coast of the U.S. but with records in almost every state.

Vagrant to Europe with several records annually in the UK.

Taxonomy

Polytypic. Consists of two subspecies.

Subspecies^[1]

• L. a. megalopterus:

• South-eastern California to western Mexico; Maine to Central America; winters to Peru

• L. a. atricilla:

• West Indies to Trinidad; winters to northern Brazil

Juvenile Photo by bobsofpa Bombay Hook National Wildlife Refuge, Delaware, USA, August 2008

First Summer Photo by bobsofpa Flamingo, Everglades National Park, Florida, USA, April 2008

Second Summer Photo by bobsofpa Fort Island Trail Beach, Crystal River, Florida, USA, August 2007

Habitat

Coastal islands, saltmarshes and sand-dunes.

Behaviour

Often gathers in large flocks in beachfront areas on lawns, park areas, parking lots, etc.

Diet

Omnivorous - diet includes fish, insects, carrion, mollusks, eggs, worms, young birds, etc. Collects food by foraging on beaches and shallows; does not submerge in search of food like some other shorebirds.
They are scavengers as well as hunting small prey.

Breeding

A large nest is built of grass and placed on the ground. 3-4 greenish eggs are laid and incubated for about 21 days.

Vocalisation

A laugh-like ha, ha, ha, ha. Also a yelp similar to Common's kee-agh

References

1. Clements, JF. 2008. The Clements Checklist of Birds of the World. 6th ed., with updates to December 2008. Ithaca: Cornell Univ. Press. ISBN 978-0801445019.

1. Collins Field Guide 5th Edition
2. Collins Bird Guide ISBN 0 00 219728 6

• List of references

External Links