Aggression among female lapwings, Vanellus vanellus

Social monogamy is the most common pair bond in birds and one hypothesis for its prevalence is that already mated females ('residents') prevent other females from establishing a pair bond with their mates ('competition for male parental care' hypothesis). To investigate this hypothesis we experimentally induced aggressive behaviour in resident female lapwings by presenting a female dummy conspecific, and a male dummy as control, near their nests. Females attacked both dummies. However, the female dummy was attacked more often than the male during the 5-min trials. Attacks on the female dummy were mostly on the ground (88%, N = 27 resident females) whereas the male dummy was attacked either by aerial dives (53%) or on the ground (47%, N = 24 resident females). Frequency of attacks on the female dummy decreased over the incubation period, whereas there was no such trend with the male dummy. These results suggest that female lapwings attempt to prevent their mates from attracting a new mate and thus try to monopolize their parental care. Other competing hypotheses for the explanation of aggressive behaviour in female lapwings are also discussed but were not supported by our data. (C) 1997 The Association for the Study of Animal Behaviour.