The Dance of the Laysan Albatross, Diomedea Immutabilis

Abstract

AbstractThe behavior of the Laysan Albatross, Diomedea immutabilis, was studied on Midway Island for a total of 11 months on three separate occasions. The courtship dance and agonistic behavior were of particular interest. The Laysan performs many individual postures in its dance but most often these are grouped into four posture sets: Eh-Eh Bow-Stare and Whinny-Head Flick-Rapid Bill Clapper, Air Snap-Bill Under Wing-Sky Snap, Stare-Sky Call, and Head Shake and Whine-Stare-Head Flick-Rapid Bill Clapper. Simultaneous displays of Bill Touch and Bow-Clapper separate individual posture and posture set performances throughout a dance. A dance consists of a beginning, a core, and a usually abrupt ending. Tempo is set by the male in the beginning. A general alternating pattern of Air Snap-Bill Under Wing-Sky Snap and Stare-Sky Call is shown by individual birds such that the Air Snap-Bill Under Wing-Sky Snap of one bird is performed simultaneously with the Stare-Sky Call of the other. Head Shake and Whine-Stare-Head Flick-Rapid Bill Clapper disrupts this pattern which may be restored by modification of display performance by one of the dancers. Only non-breeding birds and pairs breeding for the first time dance. An associative period follows dancing, which is similar to that seen after reunion of the breeding pairs before the egg is laid, and prior to nest exchange. Association in unpaired birds is the first definite indication of the establishment of a bond between them. Males actively defend an area termed the home base, established in earlier visits to the colony. Males solicit passing females from it. Territorial directives change to the nest site after its establishment by the female. Pairs return to the same home base throughout the duration of their bond. Two birds in close proximity on one particular spot necessitates a mechanism negating or reducing aggressive tendencies. Among other functions, it is hypothesized that the dance, and the associative period following, effectively reduce the threshold for attack so that the bond may be continued. The behavior of Laysan Albatrosses in their tenacity for particular sites suggest that, in addition to particular individuals, a bond is made to geographical spots. Association of lowered aggression, indicated by successful dancing and the associative period, with a site may serve to bring the female to the site and perpetuate the bond.