Birds of Chignik Lake: Glaucous-winged Gull – So… What’s Up with the Red Dot?

One of Chignik Lake’s Glaucous-winged Gulls, in non-breeding plumage, surveys the shoreline for salmon scraps. (Chignik Lake, November 2, 2016)

Rubbery-looking pink legs and feet, splotchy-brown neck and head (in non-breeding plumage), thick bill and overall large size quickly narrow the choices when trying to determine the identity of this gull. If you’re in the Pacific Northwest, possibilities are further whittled down. Check for a dark brown iris. Finally, if the gull you’re looking at has wingtips of gray rather than black, it’s a Glaucous-winged.

Perched on an abandoned lakeshore house on a rainy day. Note the toenails. (Chignik Lake, November 12, 2016)

Although there are even more Glaucous-wingeds at Chignik Lagoon and along the nearshore ocean, as long as there is open water there are bound to be a few of these omnivores cruising the lake and river. When it comes to food, virtually anything is on the menu – including the eggs and chicks of other birds and even of their own species. These birds have no qualms about hanging out at the local dump.

This is a second winter Glaucous-winged. Note the overall more brownish-gray plumage and the dark bill tip. Glaucous-wingeds don’t begin breeding until at least their fourth year. (Chignik River, October 9, 2017)

In breeding plumage, the Glaucous-wing Gull’s crimson bill spot contrasts distinctively with its amber-yellow bill. (Chignik Lake, August 19,  2016)

During summertime visits to a seashore or lake, you’ve no doubt noticed the bright red dot on the lower bill of some gulls. Well, we can thank Dutch scientist Niko Tinbergen for figuring out its purpose.

He noticed that adults returning to the nest didn’t feed the chicks until the chicks pecked at the dot. He devised experiments in which he changed or covered the dot. The result was that the chicks didn’t get fed. So this dot – which is particularly obvious during nesting season – is a vital marker in triggering a response from chicks to tap the adult’s bill, and for the adults to then regurgitate a meal.

As the behavior of the chicks appeared to be instinctive, Tinbergen’s observations became important in debates regarding animal behavior: how much is learned verses how much is innate. For his contributions to the science of ethology, in 1973 he was awarded a Nobel Prize.

Glaucous-Winged Gull. (Chignik Lake, August 19, 2017)

Glaucous-winged Gull Range Map: with permission from The Cornell Lab of Ornithology, Birds of the World

Glaucous-winged Gull Larus glaucescens
Order: Charadriiformes
Family: Laridae
Larus: from Latin for (large) sea bird
glaucescens: New Latin glaucous from Greek glaukos. In English – dull grayish green or blue in color

Status at Chignik Lake, 2016-19: Common mid-Spring through fall; Uncommon or Absent in Winter

David Narver, Birds of the Chignik River Drainage, summers 1960-63: Abundant

Alaska Peninsula and Becharof National Wildlife Refuge Bird List, 2010: Common Spring through fall; Uncommon in Winter

Aniakchak National Monument and Preserve Bird ListPresent

loon silhouette

Previous: Mew Gull – The Gull of The Lake

Next Article: Great Horned Owl

© Photographs, images and text by Jack Donachy unless otherwise noted.

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