Tweeters-

I'm not sure I buy into the length of day theory because I find all the owls
vocal at this time of year. Since Great Horned Owls nest earlier, and
Spotted Owls later, than Barred Owls, I would expect a progression of vocal
"reawakening" for these species, but I find them all to start calling more
in roughly the same time frame.

I think it has more to do with the ending of care for juveniles. Territories
shrink when taking care of juveniles, concentrating around the nest area.
These areas tend to get depleted of prey. Adults can now move around more to
find prey and can spend their time finding out what other owls are in the
vicinity. The way to do this is to move around and broadcast presence.

This time of year is also the best acoustically. Sources of outside noise,
such as from streams, are low. There are more likely to be inversions, which
keep sounds near the ground and more likely to be heard at a distance. For
those of us listening for owls, more owls can be heard simply because the
conditions to hear owls are generally much better this time of year.

I also find more interplay between owl species this time of year, by which I
mean I'm more likely to have 2 or 3 species calling at the same time. I am
more likely to find the owls farther away from their nesting core areas, and
sometimes find Barred Owls more over in adjacent Spotted Owl territories,
while the Spotted Owls are more over in Barred Owl territories. Great Horned
Owls seem to be moving around more and I also find more Saw-whet Owls, with
the "skiew" call seeming to be used more often.

It may be this is the times of year, aided by the good acoustics, for the
owls to re-establish boundaries and find out what may be new in a larger
area. It's not an easy thing to test for the specific reasons, and all
theories are somewhat guesses. Whatever the reason, this is a good time of
year to be out trying to hear owls, and the nights in and of themselves, are
beautiful, quiet, either filled with stars or a big moon, and the
possibility of a shooting star or two.

Bob Pearson
Packwood, WA
rrpearson at centurytel.net