Hey all-

My take on this is that Great Horned Owls just aren't going to hunt
during the day. Having lost the element of surprise, it probably
couldn't grab a grouse. But Great Horned Owls are top predators. They
will eat just about anything. AllAboutBirds (one of cornell's bird
sites) lists them as eating mostly mammals, but also things like
geese and herons. I've heard of them taking skunks. Undoubtedly a
Great Horned would snag a grouse if it had the opportunity. Also,
I'll throw out there that I think I heard about Great Greys taking
grouse in Minnesota the winter of the huge invasion, when the birds
were plentiful enough for ltos of behaviors to be observed. I think
the reason the grouse were not scared was that they already knew the
predator was present.

Jesse Ellis
Seattle, WA

At 9:57 PM +0000 1/15/09, johntubbs at comcast.net wrote:
>Hi Paul and everyone,
>
>I don't know the answer to this for certain, so I can only wager a
>guess. My guess would be that Great Horned Owls are adapted for
>hunting rodents and small mammals and aren't built for catching
>large birds like grouse (and of course grouse are diurnal and it
>would be highly unusual to find a Great Horned Owl hunting during
>the day). No doubt an owl would take a roosting Sharp-tailed at
>night given the chance, but the grouse probably roost in pretty
>inacessible locations for that to happen. As far as avian predators
>of grouse, my guess would be that those would be limited to Northern
>Goshawk (definitely known to take forest grouse), Gyrfalcon and
>potentially eagles. Sharp-tailed Grouse are approximately twice the
>weight of a Cooper's Hawk and are heavier than all the falcons
>except Gyr, and I believe that Peregrine and Prairie Falcons
>typically take their avian prey on the wing rather than on the
>ground. Sharp-tailed's probably have a lot m! ore to fear from
>coyotes (and habitat loss, of course) than from other birds.
>
>John Tubbs
>Snoqualmie, WA
><mailto:johntubbs at comcast.net>johntubbs at comcast.net
><http://www.tubbsphoto.com>www.tubbsphoto.com
>
>
>
>
>
>-------------- Original message --------------
>From: "Paul Webster" <paul.webster at comcast.net>
>
>Thanks, John,
>
>for the nice report on your owling trip, even though it was tough
>that the Great Gray wasn't home when you stopped by. I was
>interested in your description of the Sharp-tailed Grouse so close
>to a Great Horned Owl -- because in December 2005 we were on an
>Okanogan trip led by Kraig Kemper, and drove up the Bridgeport Grade
>Rd in search of Sharp-tailed Grouse. We stopped near the top and
>hoped to find grouse in the small brush-like trees and spotted
>instead a Great Horned Owl. "Darn", I thought, "we're not going to
>find any Sharp-tailed Grouse near here!" But a few moments later
>someone located a half-dozen Sharp-tails in a tree relatively close
>to the owl. Why would this be? Perhaps they feel safe near this big
>predator if there are several of them? Perhaps the owl won't attack
>a group of them? Or perhaps it's because it was daytime and the owl
>hunts only by night? Does anyone know?
>
>Paul Webster
>Seattle
>paul.websterATcomcast.net
>
>----- Original Message -----
>
>From: <mailto:johntubbs at comcast.net>johntubbs at comcast.net
>To: <mailto:tweeters at u.washington.edu>tweeters at u.washington.edu
>Sent: Tuesday, January 13, 2009 11:39 PM
>Subject: [Tweeters] Waterville Plateau and Okanogan Highlands Owls
>
>Hi Everyone,
>
>With all the recent owl posts, I'll add one to the mix. Marv
>Breece, Mason Flint, Evan Houston and I just completed a three day
>trip to north-central WA and had pretty good luck with owls. We
>dipped on Great Gray Owl, despite spending pre-dawn (cold!) hours
>and waiting until past dark watching the meadows and forest edges at
>the Havillah Sno-Park.
>
>However, we did see GREAT HORNED OWL (7!), NORTHERN PYGMY-OWL (great
>looks at 2), LONG-EARED OWL and SHORT-EARED OWL. By far the most
>interesting Great Horned Owl (GHOW) sighting occurred on Conconully
>Road along Scotch Creek. We found multiple Sharp-tailed Grouse in
>clumps of trees in that area, and while studying one particularly
>close and cooperative grouse, someone said, 'Say, is that big clump
>in the middle of the trees an owl?!' Sure enough, there was a
>roosting GHOW in the same tree as the grouse, within a very short
>distance of the grouse. We speculated that this did not speak
>well to the Darwinian genetic makeup of the grouse sharing the same
>tree...!
>
>We arrived at Scotch Creek well before dark and slowly drove other
>roads in the area looking for owls, and found a LONG-EARED OWL
>perched on a fence post along Silver Hill (Happy Hill) Road. It
>gave nice looks in the car headlights before another vehicle came by
>and flushed it.
>
>The two NORTHERN PYGMY-OWL were found perched in tree tops along
>Hungry Hollow Road and Chesaw Road.
>
>The SHORT-EARED OWL - an unexpected and pleasant surprise - gave us
>a close-up in-flight show while hunting in mid-morning along Mary
>Ann Creek Road on Sunday, a very gorgeous day on the Okanogan
>Highlands. It circled a field within a few yards of our car several
>times, including an unsuccessful hunting plunge into the snow,
>before flying off.
>
>We'll do a more complete report touching on other winter specialty
>birds (suffice it to say we had an excellent trip in that regard)
>shortly. Evan got some extremely good digiscope images of Bohemian
>Waxwing, Gray-crowned Rosy-finch and Pine Grosbeak among others.
>
>John Tubbs
>Snoqualmie, WA
><mailto:johntubbs at comcast.net>johntubbs at comcast.net
>
>
>
>
>
>_______________________________________________
>Tweeters mailing list
>Tweeters at u.washington.edu
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--
Jesse Ellis, Ph. D.
Neurobiology and Behavior
jme29 at cornell.edu
111 Mudd Hall
Cornell University
Ithaca, 14853