GULLS

Gulls are seabirds. They are most closely related to the terns, and more distantly to the waders, auks and skimmers. They are in general medium to large birds, typically grey or white, often with black markings on the head or wings. They have stout, longish bills and webbed feet.

Identification
The term gull refers to members of a group of 23 North American bird species that belong to the family Laridae, subfamily Larinae. Gulls are robust birds with webbed feet, long wings and a slightly hooked beak. They all possess exceptional flying ability. They are often seen swimming, and occasionally dive underwater. Adult gulls are white, with varying patterns of gray and black over the back, wings, and head. The young of larger species are often gray and take several years to develop adult plumage. The sexes are similar in appearance.

Distribution
The herring (Larus argentatus) and ring-billed (L. delawarensis) gulls are the most common and widespread of the species. They are distributed throughout North America, from coastal to inland areas, from unsettled areas to the downtown cores of large cities, from farmers’ fields to fast-food outlets and drive-in theaters. Other common species include the laughing gull (L. atricilla), Franklin’s gull (L. pipixcan), great black-backed gull (L. marinus), and California gull (L. californicus). Some species are limited to coastal habitats, while others may occur inland seasonally, rarely, or in specialized habitats.

Food Habits
Gulls feed on land or water on aquatic animals, terrestrial invertebrates and small vertebrates, plant remains, carrion, and refuse. They frequently take the eggs and young of other nesting seabirds. Small species, including ring-billed, laughing, and Franklin’s gulls, may also feed in the air on flying insects.

General Biology, Reproduction, and Behavior
Most gulls nest in colonies on sand-and gravel-covered shorelines and islands. They build nests on the ground and produce 3 to 5 eggs per nest. In the Great Lakes region, the number of ring-billed gulls has been increasing at about 10% per year since the early 1970s. The ring-billed gull yields readily to persecution, is easily driven from its breeding grounds and seems to prefer to breed in remote, unsettled regions far from the haunts of man. However, a colony on Leslie Spit on the waterfront of Toronto, Ontario, increased from 20 pairs in 1973 to 75,000 to 80,000 pairs in 1982. It appears that ring-billed gulls have changed some of their habits in recent years and have adapted to humans in their environment. A colony of laughing gulls in the Jamaica Bay Unit of Gateway National Recreation Area, New York, increased from 15 pairs in 1979 to 7,600 pairs in 1990.

Damage
Increasing gull populations in North America during the past century have led to a variety of problems for different segments of society. Gulls cause damage to agricultural crops and threaten human safety at and near airports. They are involved in more collisions with aircraft than any other bird group because they are numerous and widely distributed. The presence of gull roosts near reservoirs increases their potential for transmitting diseases to human populations. Gulls occasionally cause a nuisance when they nest on rooftops and seek food from people eating out-of-doors. Gulls are predators of several seabirds during the breeding season. Expanding and colonizing gull populations may have detrimental affects on the breeding performance of these other, often preferred, species.

Legal Status
Gulls are classified as migratory species and thus are protected by federal and, in most cases, state laws. In the United States, gulls may be taken only with a permit issued by the US Fish and Wildlife Service. Permits are issued only after frightening techniques, physical barriers, or both have been used correctly and qualified personnel certify that these methods have been ineffective. Some states may require an additional permit to kill gulls. No federal permit is needed, however, to frighten or mechanically exclude gulls.


Damage Prevention and Control Methods

Exclusion
Construct complete enclosures of plastic or wire mesh.Suspend parallel wire or monofilament strands over area needing protection. Use porcupine wires on roosting sites.

Cultural Methods
Reduce or eliminate sources of food, water, and nesting or resting sites.

Frightening
Auditory and visual frightening devices can be effective for limited time periods. Avitrol®.

Repellents
Polybutenes.

Toxicants
DRC-1339.

Fumigants
None are registered.

Trapping
Rocket or cannon netting over bait. Box trapping over nests and eggs. Spotlighting and netting by hand at night.

Shooting
Shooting with rifle or shotgun under special permit.

Other Methods
Removal of nests, eggs, and young. Sterilization of eggs.Removal of nests, eggs, and young. Sterilization of eggs.




ACKNOWLEDGEMENTS
The above information was adapted from PREVENTION AND CONTROL OF WILDLIFE DAMAGE with permission of the editors, Scott E. Hygnstrom, Robert M. Timm, and Gary E. Larson (Cooperative Extension Division, Institute of Agriculture and Natural Resources University of Nebraska-Lincoln, United States Department of Agriculture Animal and Plant Health Inspection Service, Animal Damage Control, Great Plains Agricultural Council Wildlife Committee).