Portal de Periódicos da CAPES

A Correlation Analysis of the Daily Distribution of Displays and Sexual Behaviours in Semi-Wild Mallards: Anas platyrhynchos

1976; Ubiquity Press; Volume: 16; Issue: 1 Linguagem: Inglês

10.5334/pb.580

2054-670X

Jacques Balthazart,

Animal Behavior and Reproduction

This paper describes the daily and seasonal variations of the social displays and sexual behaviour exhibited by a population of semi-wild mallards living in the natural reserve Le Zwin (Belgium). The seasonal variations already observed by Weidmann (1956) and Lebret (1961) arc confirmed. It is shown that the social displays present a daily bimodal activity pattern with higher activity in the early morning and late afternoon. Rather surprisingly the copulations and related behaviour present a different daily distribution and occur preferably around noon. Some implications of these differences in daily distribution arc discussed. The number of males in the pond is shown to be positively correlated with the frequency of social displays observed thus indicating that one of the most important activities of swimming mallards is to engage in social display. These facts arc in good agreement with observations realized on another Anas species, the Greenwinged Teal (Anas c. crecca). A possible effect of the time of sunrise on the daily activity pattern is also suggested. No short-term periodicity can be detected in the general activity observed on the pond by the use of the auto-correlation function. The cross-correlations are shown to be a useful tool for behavioural studies. Finally some methodological remarks arc formulated concerning a method for data filtration which prevents the occurrence of some meaningless correlations.