ABSTRACT
As Dunnet (1996) pointed out, opportunism, selection and availability are “in fact shorthand for very complex biological interactions about which we know only a little in quantitative terms”. Strictly applied, the term “opportunistic” predation can be taken to imply that prey are taken as encountered, with the implication that prey availability is the only criterion affecting diet choice. Following the theory of optimal diet selection (e.g. Pulliam 1974), observation of opportunistic predation (sensu stricto) might be taken to imply that high quality prey are relatively rarely encountered. However, the term is probably used at least as often as a catch-all phrase which indicates no more than that evidence for active selection was not found (and often was not sought).
