Tweeters,

In about 1985 Chuck Henny of the U.S. Fish and Wildlife Service contacted
me to request a summary of bald eagle breeding survey data which compared
productivity of northern Puget Sound bald eagles with those of southern
Puget Sound. Using an artificial east-west line drawn across the tip of
Foulweather Bluff (dipping at one point to include all of Whidbey Island
in northern Puget Sound), I produced the summary. Dr. Henny was looking
for evidence that contaminants associated with the extensively urbanized
southern Sound were affecting the reproductive health of bald eagles.

In the initial summary, northern Puget Sound bald eagles were indeed more
productive than southern Puget Sound bald eagles. I decided that I should
exclude the bald eagles of Hood Canal from the southern Puget Sound group
because Hood Canal is discrete and not directly influenced by the sizeable
urban areas that were suspected of having an influence. When I took the
Hood Canal birds out of the south Puget Sound group, the productivity of the
southern Puget Sound group improved! It was now comparable to that of
the northern Puget Sound group.

The Hood Canal bald eagles, though relatively few in number, were reproducing
so poorly that they significantly brought down the average of all of southern
Puget Sound.

In the last five years, the number of known nesting pairs on Hood Canal has
fluctuated between 23 and 26. Between 1980 and 1995, we have gathered 230
observations of nesting activity and productivity for the Hood Canal eagles.
Fifty-seven percent of nesting attempts have failed. An average of 0.67
young have been raised per nesting attempt. For the remainder of the Puget
Sound shoreline, only 32% of 1,899 monitored nesting attempts have failed
and an average of 1.01 young have been raised per nesting attempt. These
data fairly well illustrate the reproductive depression evident in Hood Canal
bald eagles.

Because Mike Waller asked about it (and because I am writing a bald eagle
status report), I contacted Mary Mahaffee of U.S. Fish and Wildlife Service
to learn more about the contaminants research being conducted on Hood Canal.
I caught Mary during one of those moments when there was a functioning federal
budget. She was at work (not true today). During 1992, 5 fresh eggs were
collected (one from each of five nests). During 1993, 3 fresh eggs were
collected from 3 nests. Although in every case (I think), at least one egg
was left behind, only 1 eaglet was produced from the nests sampled. If you
go "back to Bent," I believe you will find a reference to Washington eagles
renesting after their first clutch was destroyed. In all of the instances
I am aware of where bald eagle eggs were taken, I have yet to hear of the birds
laying additional eggs to replace those removed.

Anyway, the eggs collected in 1992 had elevated levels of PCBs, furans, and
dioxins. From the four nests closest to the mouth of the Canal came PCBs
at 18-24 ppm. Closer to the bend in the Canal, 8 ppm PCBs were detected.
Reportedly, 4 ppm is sufficient to produce negative effects on embryo
development. The 1993 eggs and 1 addled egg collected in 1994 have been
analyzed and found to contain elevated levels of PCBs as well (though
not as high as in the 1992 samples).

In the last several years, blood has been taken from both adult and nestling
bald eagles on Hood Canal. These results are not available yet. Sediment
samples and starry flounder/great sculpin samples are also in process. The
U.S. Fish and Wildlife Service plans to produce a report of available results
in early 1996.

Also of some interest, eggs have been collected from Pacific Ocean coast
nests and are being held for analysis.

That's my report on contaminants and Hood Canal bald eagles. Apparently,
no one has a good idea about the source or sources of these contaminants.
The lenghty history of poor reproduction by a group of roughly 25 pairs of
eagles on a discrete body of water tells me that the problem is right there,
in Hood Canal. However, I have heard others say that we can't be so sure.

Kelly McAllister
Washington Department of Fish and Wildlife