DISCRIMINATING THE SEX OF LAUGHING GULLS BY LINEAR MEASUREMENTS

Discriminant function analysis (DFA) has been used to sex many gull sp ecies. DFA has been used to determine the sex of Laughing Gulls (Larus atricilla) from Florida using three measurements. The function derive d from the Florida population misidentified 40% of Laughing Gulls from a New York population. Laughing Gulls from New York were significantl y smaller than those from Florida (P less-than-or-equal-to 0.004). A n ew discriminant function, based on bill, total body and wing lengths, that correctly classified the sex of 92% of gulls collected in New Yor k was derived. These findings support past studies that suggest a disc riminant function derived for one population cannot be applied with co nfidence to a different population of the same species.