Thursday, March 08, 2007

Ring-billed Gulls

Often mischaracterized as seagulls, ring-billed gulls may spend their lives without ever seeing saltwater. Found in freshwater marshes, wetlands, rivers, lakes and sometimes the coast, ring-billed gulls primarily feed on aquatic invertebrates and fish. They have been known to catch food in flight, to eat eggs and even rodents, which they catch while following tractors plowing up grain fields. Yesterday afternoon, a small flock of about 15 ring-billed gulls garrulously trailed Gene's tractor as he tilled the field across the road. They could have been feasting on earthworms, but just as likely on field mice.

These gulls only winter in Missouri, primarily in the southeast lowlands. Migratory populations can be seen sporadically throughout the state from October through April as the birds head south from their breeding range. They breed near lakes and rivers from Maine to Oregon and south to Iowa and in the west, down to the Mexican border. Unlike other gulls, ring-billed gulls return to the same breeding and winter locations each year. The young often return to the place where they were born. Studies on young birds discovered that they can follow magnetic patterns to their breeding sites within their first few months.

Like a lot of birds, their numbers dropped drastically when the millinery industry was in full swing in the late 1800s. Like some birds, their populations rebounded immensely; ring-billeds are now the most common gull in America. In cities, they hang out in parking lots and city parks looking for handouts. But here, they have to catch their food before it's plowed under.

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