AGE CLASSIFICATION OF LAUGHING GULLS BASED ON SUMMER PLUMAGE

We described quantitatively 19 summer plumage characteristics and bill and foot pigmentation of 247 known-age Laughing Gulls (Larus atricill a) collected in New York during 1992-1994. There were not differences in characteristics measured for male and female Laughing Gulls. Ninety percent of 2-yr-old Laughing Gulls and 96% of greater than or equal t o 3-yr-old birds had full hoods. Fifty-seven percent of 2-yr-old Laugh ing Gulls possessed at least partial tail bands in contrast to 4% of 3 -yr-old and 0% of greater than or equal to 4-yr-old gulls. Thus 2- and greater than or equal to 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 unrela ted to age. Using the presence of absence of a distinct black-and-gray interface on the distal portion of the fifth primary, we correctly cl assified 96% of 245 2- and greater than or equal to 3-yr-old Laughing Gulls. Using this characteristic in combination with the length of dis tinct black pigmentation present on the proximal vane of the sixth pri mary, we correctly aged 98% of 244 gulls. This technique and previousl y published plumage characteristics provide rapid and accurate classif ication of Laughing Gulls in summer plumage as <1, 1, 2, or greater th an or equal to 3 yr of age.