Patterns of association between duck species in a roosting area over the wintering in Eastern Spain.

Full article

Published:

Volume 46(2), December 1999. Pages 163-169.

Language:

Spanish

Original title:

Patrones de asociación de anátidas durante la invernada en un dormidero del este de España

Keywords:

associations among species, competition, ducks, water depth, winter roosts.

Abstract:

The patterns of association of a wintering waterfowl community in a roosting zone located in Eastern Spain are studied. The global pattern of association among duck species was non-random. The structure of species clumps was such that dabbling and diving duck species always avoided each other (significant Cole´s Coefficients of Association -CA- ranging between -0.57 and -0.90). Diving duck species of the same genus associated positively although weakly (CA = +0.12) and dabbling duck species mainly avoided each other (CA = -0.10 to -0.66), although with non-significant values of the Cole´s coefficient (Table 3). Therefore, the main tendency for ducks was to gather in single-species flocks. This pattern appears to be due to species-specific depth preferences (Fig. 1) although some other factors such as anti-predatory behaviour, winter mating, exchange of foraging information or maintenance in the roosting zone of the structure generated in the foraging grounds, might also account for the observed patterns, as ducks did not forage at all in the roosting area.