[obol] [birding] Redtail eating carrion?

[Joel Geier]

Hi Ron and All,

Red-tailed Hawks do eat carrion when they can find it. They are regular
"customers" at the carrion banquet that occurs each June and July in
grass-seed fields, after countless snakes, voles, and nestlings are
chopped up by swathers.

This winter I also saw a Red-tailed Hawk picking at a gunnysack full of
dead starlings that must have fallen off a ranch truck on its way to the
dump in the Warner Valley. I was worried that this might be a source of
second-hand poisoning, depending on how the starlings were killed.

Second-hand poisoning of hawks from carrion could also be an issue in
the Willamette Valley now that the Oregon Department of Agriculture has
OK'd the use of zinc phosphide pellets by farmers to deal with vole
infestations. This is the rodenticide that killed several dozen Canada
Geese in Keizer recently (presumed to be the result of an illegal
application for a suburban, non-ag use, though I don't think the jury is
in yet on that one). The new dispensation by ODA allows spreading this
rodenticide on whole fields rather than just the vole-infested areas.

Supposedly (according to the newspaper article I read a few days ago, in
the Oregonian or Gazette-Times), someone has run tests and the the
concentrations in dead voles should not be fatal to raptors. 

The account of these tests in the article wasn't convincing to me --
hard to say if that was due to weak science, an inarticulate ODA source
or just poor journalism (I guess you could throw in skepticism on my
part). But even if it's true, there may be impacts short of immediate
mortality.

I would encourage everyone who birds in the Willamette Valley to keep an
eye out for sick raptors in the coming months, especially Red-tailed
Hawks. I thought (from a Capital Press article during another vole
outbreak some years back) that the EPA was supposed to be involved in
approving zinc phosphide applications, but either I'm wrong about that
or the federal regulations have changed.

Good birding,
Joel

On Wed, 2008-04-30 at 15:55 -0700, Ron Enck wrote:
> Yesterday on Circle Blvd, Corvallis, out in front of
> Hewlett Packard, I saw a Redtail Hawk standing on a
> dead, apparently roadkill nutria, just off the side of
> the road on the grass. He appeared to be eating as I
> drove past. Is this commom behavior for a hawk? It was
> a big nutria, seemingly too big for him to have
> killed. I have not heard of this before.
> Ron Enck
> Corvallis
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