COLONIALLY BREEDING SEABIRDS - PREDATORS OR PREY

The evolution of aggregation in seabirds is usually attributed to pred ation pressure, although many authors have argued for the role of fora ging constraints to be considered. Discriminating between factors that result in group living and characteristics arising from group living has been regarded as an insoluble problem; yet it is possible to test the predictions of the different models proposed to explain colonial n esting. The resulting explanation suggests that seabird aggregations h ave evolved in order to utilize a dispersed and unpredictable food sup ply. As such, colonial nesting leads to increased vulnerability to pre dation, rather than being a strategy adopted to combat it.