Subject: Common Murre Die-off (fwd)
Date: Aug 30 08:49:01 1999
From: Dan Victor - dcv at scn.org


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Date: Mon, 30 Aug 1999 08:37:25 -0700 (PDT)
From: Julia Parrish <jparrish at u.washington.edu>

our monitoring site in oregon - yaquina head - had high
reproductive success, despite continued predation from both
juvenile and adult bald eagles, and peregrine falcons. in
washington, our monitoring site - tatoosh island - did not
fare so well. although this colony started out strong in
june (more birds with more eggs than at any other time in
the 1990's), the vast majority of eggs were lost in the last
two weeks in june. cause was eagle disturbance as the
raptors attacked hatching glaucous-winged gull chicks. in
fact, the three main surface nesters - murres, gulls, and
cormorants - all suffered low to non-existent reproductive
success.

what happened to all of the murre chicks from oregon?
chris thompson and his crew have been tracking dad-chick
pairs as they moved up the washington coastline. i believe
he is finding large concentrations at the mouth of the
strait of juan de fuca, as well as a bolus moving into the
strait - check with him. and yes, lots of murre chicks are
dying, of starvation i believe. and no, i don't believe
this is out of the ordinary given the high success of the
oregon colonies.

i've checked with my coastal oceanography contacts and there
doesn't seem to be anything amiss re upwelling. certainly
nothing that would cause a short-term collapse of the
nearshore food web up through baitfish. also no big storms
to separate dads from chicks. then there's the added
negative evidence that no other species (or adult murres for
that matter) are washing up in great numbers. so, jon is
right - greater success means that we see relatively higher
death of chicks.

i do think we do have to worry about the processes and
forces affecting the murre populations in the lower 48 (and
bc too for that matter), just as we should worry about the
forces affecting coastal ecosystems. there are lots of
things that humans do, both intentionally and inadvertently,
that create ripples in the system. however, i don't think
we should necessarily panic at the sight of dead chicks
(although it is not a pleasant sight by any means).
everyone should remember two things: first, massive death is
not necessarily a "wrong" or bad thing, but often part of
the natural cycle of the species and the ecosystem within
which it resides; second, what is far more likely to affect
the murres, and everything else, are chronic and cumulative
effects from many different low-level sources. these are
the things we don't readily see, because they cause small
changes in any one year, but massive change when looked at
over a longer time period. remember, murres and salmon and
everything else evolved to deal with the natural dynamism
"mother nature" throws at them; they didn't evolve to deal
with the extra weights of human-induced mortality and
depressed reproductive success.

hope this helps,

j

Julia K. Parrish
Research Asst. Prof.
Zoology Dept. - UW
Box 351800
Seattle, WA 98195
(206) 616-2958 phone
(206) 543-3041 fax
jparrish at u.washington.edu