Subject: Caspian Terns and Audubon
Date: Jun 1 07:30:31 2000
From: Mike Patterson - celata at pacifier.com


You know, it's weird how resistant people can be to
straight data.

I have been working with the tern researchers on the
Columbia River. I have provided their data without
comment or prejudice.

I'm sorry that the data does not meet everyone's needs.

But here's the straight data one more time as provided
to me by the guys collecting the data on Columbia River
terns. The specific sources for these data may be more
efficiently obtained from
http://www.realtimeresearch.org/Bird_Predation.htm
maintained by the tern researchers, additional sources
are provided below. I invite you to find your own truth
from these numbers.

1. The colonies on the Columbia River are the largest in
the world. 300 times larger than the average Caspian Tern
colony. They represent 50% of the western population and
30% of the North American population.

2. While it is true that Caspian Tern colonies are dynamic.
Most traditional tern nesting sites have been so altered
by human caused change from flood control, development
and soil stabilization efforts that terns from throughout
the region have been displaced to the Columbia where, thanks
to the corps or engineers, stable, predator free sandy
islands can be found. Efforts to rehabilitate other
former colony sites have met with significant local
resistance.

3. Wild fish are PIT tagged. If one takes the total number
of fish captured by terns as a percentage of the total fish
population that gets pasted Bonneville dam (about 100,000,000
fish) one can predict the expected percentage PIT tagged
wild fish terns should catch and compare it to the actual
percentage. It is significantly lower than predicted.
Hatchery stocks are significantly higher than predicted.
Hatchery fish probably tend to feed nearer the surface, as
they were trained to do in the hatchery, leaving them more
vulnerable to terns.

4. Like it or not dams kill more fish than terns do.
200,000,000 fish are released, 100,000,000 get past
Bonneville Dam. Some of that comes from increased
water temperature, some of that comes from gas bubble
trauma, some of that comes from turbines, some of that
comes from "pikeminnows" gathering at the spillways,
some of it come from being loaded on barges and trucks,
some of that just happens because of natural selection
(not the fault of dams).

http://www.nwd.usace.army.mil/ps/juvefish.htm
http://www.nap.edu/readingroom/books/salmon/summary.html
http://www.cqs.washington.edu/index.html
http://www.streamnet.org/
http://www.fpc.org/


--
Mike Patterson Alas, to wear the mantle of Galileo,
Astoria, OR it is not enough to be persecuted
celata at pacifier.com by an unkind establishment,
you must also be right.
---Robert Park
http://www.pacifier.com/~mpatters/bird/bird.html