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Tweeters:

I acknowledge that Michael Price and Dennis Paulson have answered Mike
Patrick's questions quite sufficiently, but remember--the ultimate
evolutionary reasons why seabirds often do not return to their species'
nesting regions in their first summer are unlikely to include behavioral
'decisions' that are for the benefit of their species (like taking food
from likely breeders and their young) rather than those that yield direct
benefits for their own individual survival and/or reproduction.
Many petrels exhibit a long adolescence (delaying reproduction up to ten
years or more) in which they make no return to breeding colonies in their
first several years of life. During these years they gain skills that
allow them to better provision themselves (and later, their young). In
this period they do not incur the energetic costs of a full migration and
they do not find themselves at a colony with perhaps dwindling resources,
they can 'concentrate' on finding food, wherever. Then in the last
couple of years preceding breeding, they return to a breeding area and
practice courtship with other subadults and breeders. During their
attendance they presumably gain experience determining the distribution
of resources near the colony.


Todd Hass
Ph. D. Candidate
Department of Biology
University of North Carolina at Chapel Hill