Seabirds are a long- lived, low-fecundity species which usually display a high degree
of natal philopatry. From a population point of view, this means that agents increasing
adult mortality are much more likely to have a noticeable affect on the population than
agents affecting reproductive success. However, the real world is often far more
complicated than theory would suggest.
For the past nine years, I have studied the factors affecting the size and success of a
population of common murres (Uria algae), nesting on the last remaining breeding
colony in Washington StateTatoosh Island. On this colony, success or failure is a
fascinating mixture of ecology (as in the availability of food and the degree of predatory
pressure), and conservation (as in the chance of an oil spill or the fate of murres
foraging in areas frequented by gillnetters). Further complications arise when the
indirect as well as direct effects of various mortality and reproductive factors are
considered. For instance, although the dominant predator in the system, bald eagles, (Haliaeetus
leucocephalus), do exert a measurable direct effect (they eat murres), their indirect
effect (they scare murres) can result in near total breeding failure. And of course, one
can never forget the long shadow of El Niņo.
In this seminar, I will review what we think we know about murres, hint strongly that
studying behavior is crucial to any sort of understanding of population and
community-level patterns, and suggest ways we might marry behavior and conservation to the
benefit of populations affected by a myriad of natural and human-induced factors.
Next: A closer
look at U.S. marine science and policy programs
Last updated: December 19, 2000