By Jerry Eltzroth
I witnessed a flock of what appeared to be sea gulls frolicking in a parking lot in West Irvine a few days ago. Last week while in the Richmond Walmart parking lot, I observed sea gulls flying around that area and landing on the light poles. Folks reported seeing them in Berea too. What’s going on?
Scott Shalaway, who holds a Ph.D. in wildlife ecology from Michigan State University, had this insight into the sea gull mystery: “Most of the winter gulls seen here in the inland east are ring-billed gulls and herring gulls. Both are common along the Atlantic coast in the summer, but large populations also nest inland on the many islands of the Great Lakes.
“When winters are mild, they stay near the lakes. But when cold Canadian air masses plunge southward, gulls wander in search of open water. Small lakes can ice up quickly, but even the Great Lakes can freeze almost completely by mid-winter. When this happens, gulls head south in search of open water. During the day, they scavenge at landfills, dumpsters, parking lots, and anywhere else they can find food. At night, they roost (sleep) on ice near open water where they are relatively safe from predators.
“This raises another interesting question. How do gulls (and ducks and geese, for that matter) roost on ice all night long without their feet freezing? They use an amazing network of blood vessels that act as counter-current heat exchangers to reheat blood as it returns from the feet to the body. When blood flows into the feet, it cools quickly. But rather than freezing, venous blood flowing back to the body core is reheated by the warmer blood in the arteries.
“Furthermore, bird feet can tolerate low temperatures because they contain mostly tendons and bones and little muscle or nerve tissue. Sometimes winter flocks of gulls draw attention from crowds of both birders and non-birders.
“So that’s why we see gulls in winter. Ice freezes them out of preferred places, and they head south for open water. In the spring when the ice thaws, the gulls return north to islands in the Great Lakes and beyond.
“The most frequently seen winter gulls are ring-billed gulls. Adults are about 18 inches long and have a four-foot wingspan. The yellow bill is encircled by a black ring near the tip, hence its name.
“Herring gulls, the other common winter species, resemble ring-bills, but are larger, about 25 inches long with a five-foot wingspan. The bill is yellow, and the lower bill has a red spot near the tip.
“In nature, gulls are opportunistic scavengers. They eat fish, carrion, crabs, insects, mollusks, and almost any sort of organic garbage, including French fries and hamburger buns. Larger gulls can be quite predatory and even partake of small birds and mammals. If you’re puzzled by seeing gulls this winter, just look around. It’s probably very cold, you’re probably just a few miles from a lake or river, and there’s probably an open dumpster nearby.”