[Tweeters] Eagles and heron colonies

Hal Michael ucd880 at comcast.net
Tue Mar 3 11:06:17 PST 2015


Eagles are also a huge problem for Common Murre colonies. Historically, the murre colonies were probably in the millions and could fairly easily withstand predation by the local eagles. Now, with murres in the thousands that same predation level is excessive. We are, or should be, learning some interesting facts about food chains as we restore some species and not others.



Hal Michael
Olympia WA
360-459-4005 (H)
360-791-7702 (C)
ucd880 at comcast.net

----- Original Message -----

I also have wondered about pre-DDT eagle depredation on herons. It wold be interesting to find out if this was a common occurrence, or if it is more common now because of the decrease in salmon stocks and other food sources also used by the eagles.

Unfortunately, even if herons were always a part of the eagle diet, the heron colonies are now under increased pressure from human development, and the eagles may be a more serious problem for herons than before.

Rachel Lawson
Seattle
< rwlawson at q.com >


On Mar 2, 2015, at 11:35 PM, Deborah < dlrymnd at aol.com > wrote:





I don't won't to diminish your feelings of these attacks of eagle on herons. I am not a bird behaviorist as some on this feed, but, I think this dynamic relationship has been going on for more years than we realize.

We would have to look at past bird counts in the 50's and 60's before ddt decimated the eagle population to such a degree that the herons were able to fill the niche of being able to build nests and establish colonies in the urban setting.

I have watched herons build their nests at Talaris by the Urban horticulture center, maybe 20 or more years ago. Eagles over a few years attacked them, and the herons moved on. I think they moved to build nests on UW campus. And now there are two eagle nests raising young. One nest over by the Arboretum and the other nest now on the property of Talaris.

If my memory serves me correctly, a few years ago there was concern about eagles vs herons down by Nisqually Refuge on the south side. I wonder if it has stabilized or if the Eagles are still actively raiding the nests? And I'm sure we could talk about other nesting site's.

I guess what I'm trying to say is we do not live in a static environment, but a dynamic one.

Debbie Raymond
Dlrymnd at aol.com
Seattle, WA

Sent from my Verizon Wireless 4G LTE smartphone



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