I agree with Bonnie's assessment.   Great Horned Owls do not make a nest 
of their own and therefore always usurp the nest of another bird, often 
a red-tailed hawk since they pretty much share the same habitat.  It is 
my understanding and experience that they generally use a red-tail's 
nest from the previous year and since they nest so early, likely take it 
over with little resistance from the hawk.  But if push comes to shove 
between the two, my money would be on the owl.

Rob Gibbs
Damascus, MD

Michael Bowen wrote:

> In Kenn Kaufman's  "Lives of American Birds," the segment on Great 
> Horned Owl contains the following sentence:  "May take over newly 
> built hawk nest."
>
> Seems like that is indeed what Bonnie Ott observed.
>
> A couple of years ago, a pair of Downy Woodpeckers spent three busy 
> weeks excavating a cavity in a rotten limb of one of our backyard 
> maple trees.  As soon as they had finished, the hole was expropriated 
> by Starlings.  Easier than doing it yourself, I guess.
>
> Mike Bowen
> Bethesda
>
> D.H. Michael Bowen
> 8609 Ewing Drive
> Bethesda, MD  20817
> e-mail:  dhmbowenATyahooDOTcom
>
>