

A: The birds that ornithologists call gulls, not sea gulls, do not strictly live by the sea and often find the open spaces of parking lots a bounteous refuge, said Jessie H. Barry of the Cornell Lab of Ornithology.

Ms. Barry, who leads the Merlin Project to develop a better online bird-identification tool, said there are more than 50 species of gulls worldwide, with many found hundreds of miles from the nearest ocean. Indeed, some live primarily inland, including the ring-billed gull, which thrives in suburban settings around the United States.

"Gulls are opportunistic omnivores," Ms. Barry said.

Traditionally thought of as scavenging along beaches or swooping to the ocean surface to catch fish, they eat many things, including insects, earthworms, rodents, grains "and of course french fries," she said.

For species like the ring-billed gull, a mall parking lot offers the chance of a handout, a left-behind takeout meal and dumpsters filled with food scraps. Grassy medians and recently mowed fields can be a good source of invertebrates.

"Gulls prefer open areas where they can spot predators and take off easily," Ms. Barry said. "The roofs of shopping malls have even served as breeding colonies."