>Mike Patterson wrote:
><snip>
> Here on the Lower
>> Columbia River, the productivity is half what it is elsewhere in its range.
>> DDE, PCB's, mercury, lead and cadnium are still found at high level in
>> resident birds.
>
(snip
>Golly--Gee, I thought Nuclear Energy was the safest thing around and
>that it didn't leach into the Columbia river?????
>


My, my jumping to conclusions are we?
Hanford isn't the only polluters that drain into the Columbia. DDE
and PCB probably aren't a by-product of Hanford. I'm not sure about the
heavy metals but I doubt they are only from Hanford. Don't forget the
Silver Valley of Idaho is upstream from the Lower Columbia (its all connected).
There could be any number of explanations as to why productivity is
lower on the Lower Columbia than other places. One that leaps to mind is
slackwater. The Columbia and the Snake both have been changed from raging
rivers to slackwater pools. As the salmon and trout have decreased, the
fishing becomes tougher and eagle productivity goes down.
Lower productivity could also be due to heavy human disturbance on
the Lower Columbia.
The problem might be on the wintering grounds not the breeding
grounds. I don't know where the Baldies on the Lower Columbia winter but it
might be very contaminated with heavy metals, DDE, and PCB's.
It could also be that the Lower Columbia is just a bad place for
bald eagles to produce young and always has been. It would be interesting
to compare current productivity on the Lower Columbia to productivity on the
Lower Columbia in other time periods (before slackwater, after the start of
slackwater, etc.). Comparing the Lower Columbia to other places in its
range introduces other confounding factors (different predators, different
prey, etc.)
Clearly, the high levels of DDE are worrisome. DDT (the precursor
to DDE) is well known to cause nesting problems. However, I don't know if
anyone has studied the effects of the other pollutants on nesting baldies.
This is by no means an endorsement of nuclear power. Just a word of
caution.

Deb Beutler
Department of Zoology
P.O. Box 644236
Washington State Univerisity
Pullman, Whitman Co., WA
dbeutler at wsunix.wsu.edu