Intraspecific Variation in the Long Call of Herring Gull Larus argentatus in Eastern Baltic and Comparison with Larus cachinnans [abstract]

We compared the Long Call of coastal breeding yellow-legged herring gulls in the Gulf of Finland and those breeding inland in Teichu raised bog (E Latvia) and contrasted them with Larus cachinnans from S Ukraine. Principal component analyses of 10 Long Call parameters showed that L. cachinnans and Eastern Baltic yellow-legged herring gulls are essentially distinct in multivariate space with no overlap. Differences occur primarily in structural organization, element configurations and number, in the form, number and spread of harmonic bands within elements and intervals between elements. The Long Call of coastal gulls is the shortest, having 8 to 14 elements, the Long Call of Teichu gulls consists of 12 to 18 elements and cachinnans Long Call comprises 14 to 24 elements. A more obvious difference was observed in basic harmonic band frequency. Differences between samples from the Gulf of Finland and from Teichu are not of such major importance. They occur only in the duration of the Long Call, in element number, harmonic band form, element duration, in intervals between elements and amplitude modulation of separate elements. On the basis of our own investigations we maintain that yellow-legged herring gulls from Teichu bog breeding in the same geographical area as coastal gulls are a rather different group in relation to L. a. argentatus. We are not quite confident to state that inland gulls from Teichu bog can be a separate herring gull subspecies L. a. omissus. Partial interbreeding between these forms cause difficulties in recognizing that. The existence of omissus as a subspecies will possibly be proved later.