Habitat selection rules in breeding mallards (Anas platyrhynchos) : a test of two competing hypotheses

• Ideal preemption and conspecific attraction are alternative hypotheses of the habitat selection rules used by individuals. According to the former an occupied site is assumed to be preempted and therefore not available for later arriving individuals, whereas according to the latter individuals are assumed to be attracted by conspecifics to occupied sites, rather than avoiding them. We studied these competing hypotheses in breeding mallards (Anas platyrhynchos) by a cross-over experiment in 2 years, introducing birds onto lakes before migratory wild mallards arrived. If mallards use the ideal preemptive rule, breeding density of wild mallards in experimental lakes should be lower and they should be occupied less frequently than control lakes, but if mallards use the conspecific attraction rule the reverse should be true. Our results allowed us to reject the ideal preemptive rule whereas the conspecific attraction rule was to some extent supported. We discuss these findings in relation to population limitation. The results suggest that the local breeding population studied is not limited by spacing behaviour related to habitat selection.

Ämnesord

NATURAL SCIENCES  -- Biological Sciences (hsv//eng)

NATURVETENSKAP  -- Biologiska vetenskaper (hsv//swe)

Nyckelord

Anas platyrhynchos

conspecific attraction

habitat selection

ideal

preemptive distribution

population limitation

CONSPECIFIC ATTRACTION

TEAL

WATERFOWL

DENSITY

CRECCA

DUCKS

Biology

Biologi

Publikations- och innehållstyp

ref (ämneskategori)

art (ämneskategori)