U.S. Department of Agriculture: Animal and Plant Health Inspection Service
Document Type
Article
Date of this Version
October 1996
Abstract
We described quantitatively 19 summer plumage characteristics and bill and foot pigmentation of 247 known-age Laughing Gulls (Larus atricilla) collected in New York during 1992-1994. There were no differences in characteristics measured for male and female Laughing Gulls. Ninety percent of 2-yr-old Laughing Gulls and 96% of ≥ 3-yr-old birds had full hoods. Fifty-seven percent of 2-yr-old Laughing Gulls possessed at least partial tail bands in contrast to 4% of 3-yr-old and 0% of ≥ 4-yr-old gulls. Thus 2-and ≥ 3-yr-old Laughing Gulls cannot be separated reliably by the presence or absence of a tail band. Pink pigmentation on the breast or abdomen occurred in 12% of individuals and was unrelated to age. Using the presence or absence of a distinct black-and-gray interface on the distal portion of the fifth primary, we correctly classified 96% of 245 2- and ≥ 3-yr-old Laughing Gulls. Using this characteristic in combination with the length of distinct black pigmentation present on the proximal vane of the sixth primary, we correctly aged 98% o f 244 gulls. This technique and previously published plumage characteristics provide rapid and accurate classification of Laughing Gulls in summer plumage as < 1, 1, 2, or ≥ 3 yr of age.
Comments
J. Field Ornithol., 67(4):565-574