Gulls

Gulls

Scientific Classification

Common Name
gull
Kingdom
Animalia
Phylum
Chordata
Class
Aves
Order
Charadriiformes
Family
Laridae
Genus Species
Most species in the genus Larus; roughly 43 species total

Fast Facts

Description
In general, gulls are robust, long winged birds that have bills that are stout and hooked and fully webbed feet except for the hind toes. Unlike terns, which are found in similar habitats, gulls have broader wings and squared-off or rounded tails. Many gull species exhibit different colorations due to seasonal changes or maturity level and it is often very difficult to identify a given gull's species. Bill and leg coloration are excellent distinguishing characteristics to use identifying gulls.
Males are generally slightly larger than females and have larger bills.
Size
Generally gulls range in length from 28–81 cm (11–32 in.)
Weight
No data
Diet
Gulls are mainly scavengers, but they also prey on fishes, insects, mollusks, crustaceans, worms, mice, young birds, bird eggs, seaweed and berries.
Incubation
For kelp gulls, the eggs begin to hatch after about 27 days, and the chicks leave the nest soon after. Mortality rates can be high, as egg and chick cannibalism by other gulls results in up to 50% mortality rates in some colonies.
Clutch Size
Gulls usually nest in colonies, laying 2–3 eggs in shallow nests composed of stones, seaweed, mosses, and feathers.
Fledging Duration
They are capable of flight about 5–6 weeks after hatching and are independent at 7–8 weeks after hatching.
Sexual Maturity
No data
Life Span
Some gulls may live to 20 or more years
Range
These cosmopolitan birds inhabit many different areas of the world. For example, ringbill gulls (Larus delawarensis) are found from North America to South America and into the Caribbean; laughing gulls (L. atricilla) can be seen in Brazil, Peru, and both coasts of the United States; and kelp gulls (L. dominicanus) are distributed around Australia, New Zealand, sub-Antarctic islands, South America, and South Africa.
Habitat
Gulls inhabit coastlines of oceans, bays, and major lakes. They typically prefer to stay within sight of land - some travel far inland to find food.
Population
Global: Unknown
Status 
IUCN: 2 species of gulls are listed as Endangered
CITES: 1 species, the relict gull, Larus relictus, is listed as Appendix I
USFWS: 8 species listed as either Vulnerable or Lower Risk

Fun Facts

  1. Some gulls follow behind plows to consume upturned grubs while others are known to drop hard-shelled mollusks onto rocks to break them open.
  2. Many species of gulls are kleptoparasitic and steal prey from other birds of the same or different species. Kelp gulls have been seen to mob penguins in order to take their food, and also harass and rob other birds of their catches.

Ecology and Conservation

In the United States, the Migratory Bird Act legally protects gulls.


Bibliography

Harrison, P. Seabirds: An Identification Guide. Boston. Houghton Mifflin Co. 1983.

Line, L. The Audubon Society Book of Wild Birds. New York. Harry Abrams, Inc. 1976.

animaldiversity.ummz.umich.edu/search/simple

audubon.org/bird