The Ring-billed Gull is abundant throughout much of North America. This is the common gull in the interior, away from large water bodies, and is the gull that often flocks in mall parking lots. I noted that it is a first-cycle bird. "Cycle" refers to its molt cycle. This is a bird in its first year; a juvenile. It takes the Ring-billed Gull three years to attain (mostly) adult plumage. The larger gulls in the genus Larus take at least four years to develop adult plumage.
Lesser Black-backed Gulls are native to northwest Europe, where they frequent Atlantic coastal areas. The first record in North America was in 1934, from New Jersey. As the photo above illustrates, gulls are quite at home at sea and far from land. The distance from the gull's native haunts to the shores of America is something like 3,300 miles, but such travels are probably no great shakes for such an animal. This species has been on a westward expansion for some time. Lesser Black-backed Gulls occupied Greenland and began breeding there by 1990, and were nesting in Iceland by the 1920's.
Even though the first documented North American record dates back to 1934, these gulls remained quite the rarity on this side of the pond for about four more decades. In the 1970's, the dam burst and records began to accumulate rapidly. Ohio's first Lesser Black-backed Gull dates to 1977. We've had scores of the animals since, and it is now an expected species in fall, winter and spring along Lake Erie. Hit a good day, and you might find a dozen. There is an ever-increasing number of interior records, too. We're not unique - Lesser Black-backed Gull has now been recorded in every eastern state, and eastern seaboard hotspots can host hundreds of the birds.
Given the rather recent and abrupt boom in North American records of Lesser Black-backed Gull, it is somewhat surprising that they aren't yet breeding here. Well, they have, sort of (unless there are other very recent records that I'm unaware of). The first documented nesting was of a Lesser Black-backed that was mated with a Herring Gull in Juneau, Alaska of all places, in 1993. That was unexpected. Then, in 2007 another bird was found nesting on Appledore Island off the coast of Maine, and it too was paired with a Herring Gull. The Appledore Island bird nested - with its Herring Gull mate - for at least four consecutive years. It's probably only a matter of time before Lesser Black-backed Gulls begin pairing with their own, and nesting records increase.
In 1934, when that first New Jersey/North American Lesser Black-backed Gull caused an ornithological stir, the population of the United States was about 126,374,000 people. Today, it's about 314 million people. Gulls that prosper from our waste and cast-offs are one group of animals that benefit from unchecked runaway population growth.
Unfortunately, most animals aren't nearly so adaptable.