ACOUSTIC SIGNALLING OF THE GREAT BLACK-HEADED GULL LARUS ICHTHYAETUS PALLAS

ABSTRACT

Observations made on the behaviour and sound recordings made of the calls chiefly in the early part of the breeding season in the South Ukraine indicate that the Great Black-headed Gull Larus ichthyaetus has a limited vocal repertoire, producing only eight different types of call associated with various behavioural contexts. Sonagraphic analysis of these sounds shows that their harmonic structure is confused, like that of the calls of L. melanocephalus and L. relictus and unlike the stronger harmonic organisation of the calls of L. argentatus, L. fuscus and L. marinus. Furthermore, there is no signal warning of approaching danger. This acoustic evidence supports the theory that L. ichthyaetus is more closely related to L.relictus and other “primitive hooded” gulls than to L. argentatus and other “large white- headed” gulls of the genus.