[Tweeters] Barred Owl vs Screech, Spotted, other prey spp- habitat differences?

Stewart Wechsler ecostewart at quidnunc.net
Tue Dec 4 17:40:21 PST 2007


Since the newer immigrant Barred Owl has become common in our
state over the last 10 years in many areas where there once were more
Western Screech
Owls, Spotted Owls as well as many other species that are preyed on by the
Barred Owls, I'm interested in people's observations and thoughts on where
Barred Owl prey species will survive due to their adaptation to some
habitats that are not preferred by Barred Owls.

While Western Screech Owls were relatively frequent 7 years ago through the
wooded parks of West Seattle (the area I know best) and elsewhere in our
area, the ones that I am
aware of are now largely restricted to the steep wooded slopes above the
Puget Sound. In Lincoln Park with both flats a steep (mostly) wooded slope
above the Puget Sound, it seems that the Barred Owls are pretty much
restricted to the flat areas. The one Screech Owl I heard there 2 years ago
(at about sunset on Christmas Day) was calling from a relatively shrubby
wooded steep slope above the Sound. I'm also told that the Spotted Owls are
still surviving tend to be on steep slopes in their remaining old growth
forest habitats, while the Barred may have wiped them out in the flatter
areas of the remaining old growth forest.

It seems that Barred Owls are better adapted to relatively flat wooded
areas. I think especially medium age or older second growth, especially
near fresh water (They often hunt at the water's edge). They may prefer
being near some forest edge (that would include all urban wooded areas). I
suspect that Screech Owls will accept both all of the habitats that the
Barred are now occupying (they too like to hunt by water) as well as
accepting steeper slopes and possibly earlier successional shrubby and
young, denser woods, but now have largely been wiped out in the preferred
Barred Owl habitats.

It may be that the steeper slopes are less desirable habitats for Barred
Owls or both species, but that the Barred Owls have not yet colonized these
less desirable habitats. I had hoped that the Screech would find that part
of their niche was less acceptable to Barred and that this would allow them
to survive. I imagine that the smaller owls may be able to ascend and
descend more quickly, making it easier to hunt on steep slopes. Their
smaller size would also allow them to fly through denser shrubbery and
younger trees.

Are other people finding the Western Screech Owls (or Spotted Owls)
surviving on steeper slopes and that Barred are largely absent from these
habitats. Do you have other observations of differences in habitat that
each of these species are adapted to and surviving or colonizing / not
colonizing?

Camp Long in West Seattle, where I lead some of my nature programs also used
to have flying squirrels, though I only rarely got reports of them and was
never lucky enough to see one myself. I question whether they can persist
in relatively small islands of habitat such as city parks with so many
Barred Owls raising their young in these isolated habitats. Any other
obvservations related to the survival of prey species of Barred Owls, as the
Barreds move into new territory would be welcome.

It also seems that Great Horned Owls are declining in areas now occupied by
Barred Owls, do others have observations that relate to this possibility?
They would at least compete for some food, but I don't know how much that
would be a factor if the Barred is indeed to some degree displacing Great
Horneds.

Stewart Wechsler
Ecological Consulting
West Seattle
206 932-7225
ecostewart at quidnunc.net

-Advice on the most site-appropriate native plants
and how to enhance habitat for the maximum diversity
of plants and animals
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