Order: Charadriiformes

Family: Laridae

Genus: Larus

Species: Larus canus

The Mew Gull formerly known, and still sometimes classified as the Short-billed Gull, is the smallest of the “white headed gulls” measuring a length of only 41-46 cm and weighing 360 to 415 grams (Hoffman 1927). Mostly found on beaches and river estuaries, it is also the only “white-headed” gull known to regularly use trees for nesting. Regionally the Mew Gull exists exclusively along the west coast, with breeding regions confined to the far northwest. A well populated species at over 1 million pairs worldwide, the Mew Gull appears widely across Eurasia as well where it is referred to as the Common Gull, causing debate over the inconsistent terminology. Vocalizations and genetic testing is very sparse and has since remained generally unstudied between North American and Eurasian Mew Gulls.(Moskoff and Bevier 2002).

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Their most distinguishing taxonomic features are the ruby colored orbital ring and gape, that stand out in contrast with the pure white of breeding males. Plumage characteristic to the Mew Gull are the the black tips along the outermost primaries, that have pure white spotting towards the most anterior point (Moskoff 2002).

Mew Gulls can be particularly difficult to identify, considering the several variations of melanin and carotenoid concentrations, that can cause both deeper grays and brighter whites. Coincidentally some of these abnormalities replicate the specific identifiers of the Ring-billed Gull (Davis, J.N., and Blumin, L. 2012).

Some subtle differences in a appearance can be difficult to properly identify as their traits aslo  vary geographically. Considering the already difficult task of identifying hybridizing gulls, in and out of 4 year molts, these identifiers can be helpful (Moskoff 2002).

The Mew Gull has a dull greenish bill, that is shorter than most gulls, and comes to a pointed slight hook near the tip of the maxilla. The iris is a dull yellow with a greenish tint, and appear almost entirely dark from a distance. Leading up to winter the Mew Gull has a pinkish colored tarsus, however when wintering the coloration changes to an olive gray as they acquire their alternate 1 plumage (Vermeer and Devito 1986)

Basic plumage in breeding males is consistent with an entirely pure white head, gray colored mantle, back, scapulars, and wing coverts.

Definitive Basic plumage in winter showing largely grayish-brown mottling and brushed bown on head and neck. Eyes change to a dark amber or deep olive usually darker in breeding conditions.

Alternative Plumage during February to April when grays become deeper and more solidly gray through the back and scapulars contrasting with paler white wing coverts. The head and ventral torso reach a pure whiter through molt and wear (Moskoff 2002).

Pixabay Photo originally posted by skeeze

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