[Guide to Bird Control and Wildlife Management] Galling Gulls

The herring gull, Larus arentatus, and ring-billed gull, Larus delwarensis, are two of the more than 50 species of gulls  found throughout the United States. They are the most commonly encountered gulls in the Northeast; their range extends from Maine south and along the Gulf Coast to New Orleans. Both species can be found the length of the Mississippi River basin. The herring gull also occurs throughout most of Canada; the ring-billed gull is in the middle Plains states.

Earlier in this century, the distribution of gulls was limited to coastline areas; however, several species have extended their range significantly inland. The major attractions have been landfill areas and increased agricultural development. Because the latter two species are predators of rodents and insects, farmers have derived significant benefit from their presence in agricultural areas.

IDENTIFICATION. Gulls are distinguished from other birds based on their large size, long pointed wings, square tails, hooked bills and webbed feet. It is often difficult to distinguish species because the color of the head plumage varies seasonally from a dirty white/brown to pure white/black. The young are often dirty white to brown.

The herring gull is 23 to 26 inches long. It has a light gray back and wings, which have black tips with white spots. It has a white head and breast, a red spot near the tip of the lower portion of its bill and yellow eyes. The ring-billed gull is 18 to 20 inches long. It has a slightly darker gray back and wings, which have black tips with white spots. It has a white head and breast, a black ring near the tip of its bill and yellow eyes.

The laughing gull is 15 to 17 inches long and is easily recognized by its black head.

The greater black-backed gull is black on its back and the top of its wings; however, the wing tips are white, as are its head, breast and tail.

BIOLOGY. Both species tend to nest in colonies on the ground. The nest is constructed of seaweed, grass, sticks and feathers. Herring gulls occasionally nest on ledges or cliffs, whereas ring-billed gulls occasionally nest in low trees.

They lay two to four eggs, which are brown to olive green in color and have several darker marks. The incubation period is approximately three to four weeks. Only one batch of eggs is produced per year. Adult sea gulls provide little care for their young. The young birds have feathers when they hatch and readily move and feed themselves.

HABITS. Gulls feed on a wide variety of materials, including fish, clams, mussels, garbage, dead animals, insects, earthworms, rodents and fledgling gulls.  The ring-billed gull is the species most often found around fast food restaurants, whereas the herring gull prefers landfill areas. They often loaf in large open areas with a good field of view.

They are very gregarious birds, often roosting by the thousands during the breeding season and winter. It is not uncommon to find several species roosting together. Feeding sites can be located as far as 40 miles from the roosting area.

DAMAGE. Gulls in the urban environment are often a major nuisance. They foul public areas and residential and commercial buildings with their extremely smelly droppings. They can be very noisy and aggressive when begging for food. Occasionally they damage gardens, and affect other nesting birds. Gulls are responsible for more than 50 percent of documented aircraft bird strikes. Furthermore, they are a particular nuisance around harbors, landfills and agricultural areas.

Ring-billed gulls have adapted their nesting habitat to rooftops of buildings in some locations. The feathers and litter the gulls bring into the nest site causes roof drains to clog and water to overflow into the buildings below. They also peck holes in flat roofs covered with rubbery type coatings. The resulting leaks cause damage to the buildings’ ceilings and contents.

Fortunately, sea gulls pose little threat to human health and their ectoparasites are not a problem because they rarely, if ever, nest or loaf in populated areas.

The preceding article was excerpted from the PCT Bird Management Field Guide by Dr. Richard Kramer, a contributing technical editor to PCT magazine. Kramer can be reached at rkramer@giemedia.com. To order a copy of the Field Guide, or copies of guides covering beetles, structure-infesting flies and urban spiders, visit www.pctonline.com/store.