The simple idea of a forager seeking to maximise its long-term
expected rate of finding prey is mathematically attractive, but it
often ignores ecological reality. For example, the arrival of prey may
be unpredictable, these prey may only be present for a short time, and
there may be good reasons why the forager doesn't want to wait around
for too long. Data on Macaroni penguins feeding on krill in the
Antarctic provide an example. These data motivate some simple foraging
models which try to respect the biology yet which might offer scope
for new theoretical insight.