Hi All -

Anybody who has taken a wildlife population ecology course will tell you
that it is very hard to prove cause and effect relationships when it comes
to interspecific competition. There could be all sorts of reasons why
Western Screech Owls are declining (if they are declining) that have nothing
to do with Barred Owls. You need more than anecdotal evidence (although it
is a good starting point) and that can be hard to produce. Although not a
professional myself, I have recently taken a pop. ecology course and this
was really hammered home - I'd be interested to hear from some of the
professional wildlife folks on tweeters on this topic.

Likewise I would imagine you need more than anecdotal evidence for a species
to be considered for a watchlist. So if there is good documentation of
declines for Western Screech Owl (published or unpublished data) then I'm
sure it would be a good candidate. Of course owls, being fairly cryptic
species, are difficult to census. Some areas (e.g. Canada) have instituted
systematic owl monitoring projects to try to get at this. Birders can
certainly help with these kinds of projects - for example there are many
Breeding Bird Survey (BBS) routes around the country that go unrun every
year.


thanks, Charles.

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Charles Swift
charless at moscow.com
Moscow, Idaho
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