Ring-billed Gull
The following photographs were taken March 18 in Ithaca, New York.
Ring-billed Gulls go through a series of molts and reach their adult (definitive) plumage after three years. They molt head and body feathers from February to April, as illustrated by the following images. (Humphrey-Parkes system in parenthesis)
First winter Ring-billed Gull, (undergoing first prealternate molt--first basic to first alternate plumage). Note the dark tip to the bill, streaking on chest, neck and head and the brown in the wing coverts. Many of the feathers are badly worn.
This is a second winter Ring-billed Gull (undergoing 2nd prealternate molt--from 2nd basic to 2nd alternate). Note the yellow tip on the bill, light streaking on the crown, the black on the shoulder of the bird and the black wingtips with little to no white markings on the tips of the feathers.
Ring-billed gulls go through a head and body molt from February to April. Note the ragged edges to the scapulars (A) and the median coverts (B). In comparison, the greater coverts (C) and secondaries (E) do not show as much wear but are from the same molt period as (A) and (B). The black feathers (D) are the tips of the primaries.
Despite the obvious wear, the scapulars and coverts will not be replaced until a complete molt occurs later in the year, typically between June and October (inclusive).
All images ©Sam Crowe/CLO