>There have been few Snowy owls this year, but I saw several (8 or 9)
>Pomarine Jaegers on the March 11 pelagic trip out of Newport, OR.
>Both populations apparently fluctuate with the lemming population
>up North. Just wondering if their fluctuation occurs in alternate
>seasons?/years?
>
>Neil J. Fergusson

Neil, there's probably no way you can use data from Washington to get at
this question. We're at the southern edge of the range of the Snowy Owl,
and I don't think we yet know exactly why there are more some years than
others. My hypothesis is still that we get a lot of birds after very
successful breeding years. An alternative hypothesis is that we get a lot
when feeding conditions are bad farther north.

Pomarine Jaegers, on the other hand, winter to the south of us, and all the
adults have to fly by whether they had a successful year or not, so we will
always see lots of them. It may be that breeding success can be estimated
from the proportion of juveniles seen in the fall, but we have to realize
that we're getting them from all across their Arctic range, as all of them
winter at sea. So there's not even any way of knowing which populations
were successful or unsuccessful in a given year (it surely varies across
the Arctic).

Dennis Paulson, Director phone: (206) 756-3798
Slater Museum of Natural History fax: (206) 756-3352
University of Puget Sound e-mail: dpaulson at ups.edu
Tacoma, WA 98416