The reports coming in on shearwaters have finally gotten me to sit down and
respond. This die-off of shearwater phenomenom has occured roughly every ten
years since I've been in Virginia (since 1969). Each time it occurs it's as if
it never happened before. But each one has been reported in North American
Birds. The symptoms are the same and the species most affected is the Greater
Shearwater. The dead birds all are emaciated and have protruding keels with
reduced musculature and fat. At the same time coastal fishermen report that
the shearwaters are diving on their bait in such a frantic manner that they
can't even get the bait below the water's surface. Many even catch them on
their lines and they report that every bird is emaciated. My explanation for
each of these events is that the birds are starving. That means there are
either many more shearwaters than usual coming north for the summer or the
available food for them has been dramatically reduced by some change in one or
more ecological parameters. The first explanation could be checked through
researchers who study the shearwaters at breeding locations like Tristan de
Cunha in the South Atlantic to see if abnormally high productivity occured this
year. The other explanation could be tested by asking the fishermen
specializing in catching squid, a favorite shearwater food, to see if they're
having a terrible year catching any. As you can tell even though I've been
through several of these events, I've never done the work of following through
on these ideas. So....perhaps there's somebody out there with a strong
interest in pelagic species, or just finding out the answer, who will take the
challenge. Any takers? Comments to me should be offline, but if you deem them
of sufficient general interest (your call), you can post them to the listserve.
Cheers,
Bob
Robert L. Ake
6603 Catherine Street
Norfolk VA 23505
