Wayne - Thanks for your detailed response. I agree that controlling
cowbirds and barred owls are very important components of Kirtland's
warbler and Spotted owl survival. Until 2009, I had worked in
southern CA surveying/monitoring Least Bell's vireo and SW willow
flycatchers for 30 years (with some time surveying CA gnatcatchers),
and know first-hand what I consider the absolutely necessary benefit
cowbird control has on the former two; CAGN I rarely saw in Ventura,
so not sure if BHCO control would help or not -- the several nests of
which I am aware during 1995-2005 indicate they might not be as
readily impacted by cowbirds, at least at the "periphery" of their
range... others more knowledgable than I should comment on them... I
"conducted" a personal experiment, after several years of intense
cowbird control AND LBV nest searching and monitoring along the
Ventura and LA portions of the Santa Clara River in CA: one year,
after nearly 6 years, there was no money for cowbird control.
Parasitism and dumped eggs and chicks, as a function of "nest
outcome" rose from ZERO [n for nests per year being about 50-120] to
over 10% of the nests found in that non-control year; AND, as cowbird
traps have been decreased on the river, I found more parasitized
nests where I'd not encountered them since prior to trapping, to me
indicating failed reproductive replacement potential, and making me
conclude that trapping is absolutely essential to the prolongation of
LBV in its northern most river systems. So, the issue to me is that
simple: as long as habitats are string in shape between urban
developments [as along S CA rivers], AND we feed cowbirds all winter
in feed lots and horse corrals, there will always be a need to
"ameliorate" the impacts of that pest for some species. Likewise, as
per your point about changes from "old growth" of one type or mix of
forest into something "not" native to the NW and Central CA regions,
Barred owls should be controlled, if at all possible. However, I do
not hold out much long term hope for either, given the bankruptcy
into which our nation appears to be headed. Nature always takes a
back seat to largesse for other purposes. Thanks again! - JIm

At 08:13 PM 12/10/2009, Wayne Weber wrote:
>Jim,
>
>Apology accepted. As most of the people on TWEETERS probably know (I've been
>a member for 10 years), I am a professional biologist with a Ph.D. in
>ornithology, and I am certainly not an anti-evolutionist. Among other things
>that I did in my career with the B.C. government, I wrote one detailed
>report on Spotted Owls and compiled a comprehensive bibliography of the
>species, so I do have some specialized knowledge of the species' biology,
>although I haven't studied them in the field myself.
>
>I'd like to address a couple of points you raised. In relation to Kirtland's
>warblers, it is generally recognized that a shortage of its preferred
>habitat (5 to 10-year-old jack pine stands) was one of the main reasons for
>its rarity, and steps were taken to increase this habitat in Michigan and
>Wisconsin. However, cowbird parasitism became so severe that the warblers
>would probably have gone extinct without cowbird control BEFORE an increase
>in habitat could be accomplished. Cowbirds don't seem to like really large
>areas of young jack-pines, so hopefully if large enough areas are created,
>the cowbird problem will decrease.
>
>New habitat can be created for Kirtland's Warblers in 10 years or less, by
>clearing a forest and planting young jack pines. Unfortunately, it isn't so
>easy to create new Spotted Owl habitat; because they prefer old-growth
>forest, it would take 200-300 years to create new habitat from scratch.
>
>The actions that were taken during the 1990s (e.g. the Northwest Forest
>Plan) should have slowed, if not stopped, the decline of Spotted Owls in the
>Northwest. Unfortunately, the sharp decline seems to have continued unabated
>in most areas, even without further habitat loss. Barred Owls seem to have
>displaced Spotted Owls from most forests, even old-growth forests, below
>2000 feet altitude, and even many forests above that level. It really looks
>like Barred Owl competition, not habitat loss, is the main cause of the
>continuing Spotted Owl decline in the last 10-15 years. Habitat preservation
>or creation alone will not save the Spotted Owls.
>
>This brings up your second point: whether or not Barred Owls are "native" to
>Washington. They first arrived here only in the 1970s, so they were not part
>of the ecosystems in which Spotted Owls evolved. Until about the 1940s,
>Barred Owls were unrecorded west of the Rockies. It could be debated whether
>or not their range expansion was caused or assisted by humans. Although
>there is little critical evidence one way or the other, my belief is that
>extensive logging in central B.C. and the growth of second-growth deciduous
>and mixed stands, which Barred Owls prefer over pure conifer stands, was a
>key factor in the Barred Owl's spread across the Rockies and into Washington
>and Oregon by way of British Columbia.
>
>Whatever the cause of the Barred Owl's range expansion, they are here in
>large numbers now, and they are certainly having a detrimental effect on
>Spotted Owls (and probably on Western Screech-Owls as well). Even if the
>decision is made to try to control Barred Owl numbers in some areas, it
>would not be possible (or desirable) to do this throughout the area where
>they overlap the (Northern) Spotted Owl's range. It may be that despite all
>we can do, Northern Spotted Owls will disappear from most or all of their
>range, except in the few areas where Barred Owl control is carried out. I
>think we owe it to the Spotted Owls to at least attempt the experiment,
>rather than to just stand idly by and watch as Northern Spotted Owls slide
>downward toward extinction.
>
>
>Wayne C. Weber
>Delta, BC
>contopus at telus.net
>
>
>
>
>
>-----Original Message-----
>From: tweeters-bounces at mailman2.u.washington.edu
>[mailto:tweeters-bounces at mailman2.u.washington.edu] On Behalf Of Jim Greaves
>Sent: December-10-09 2:38 PM
>To: tweeters at u.washington.edu
>Subject: [Tweeters] Re: Kirtland's and cowbirds
>
>I have no problem with the gist of what is said about cowbird
>control. But, keep in mind that the "god" of Kirtland's Warblers came
>out years ago opposed to cowbird control because he contended it
>didn't really work. Habitat loss is the key. Without retaining and
>increasing the appropriate pine forests for Kirtland's, they will
>always be in short supply, endangered, and in need of aggressive
>(assertive?) protection from those ecological elements that benefit
>from humans to the detriment of other native birds and wildlife.
>Also, I apologize for my stupid comment about Mr. Weber being an
>"anti-evolutionist" - I was in error and only being flippant - Jim
>Greaves, Thompson Falls MT
>
>At 01:00 PM 12/10/2009, tweeters-request at mailman2.u.washington.edu wrote:
> >Message: 14
> >Date: Thu, 10 Dec 2009 10:23:43 -0800
> >From: "Wayne Weber" <contopus at telus.net>
> >Subject: RE: [Tweeters] RFI killing barred owls to save spotted owls
> > in Cle Elum area
> >To: "TWEETERS" <tweeters at u.washington.edu>
> >Message-ID: <004201ca79c5$e815ee30$b841ca90$ at net>
> >Content-Type: text/plain; charset="us-ascii"
> >
> >Jo and Tweeters,
> >
> >There should be nothing disturbing about this proposed action. It has been
> >proposed and seriously considered by wildlife agencies for quite a few
> >years. Spotted Owls are threatened, Barred Owls are not; Spotted Owls are
> >native to Washington and Oregon, Barred Owls are not.
> >
> >For comparison, the Kirtland's Warbler exists today only because many
> >thousands of cowbirds, which were parasitizing them and severely reducing
> >their breeding success, were trapped and killed on the breeding grounds.
>The
> >cowbird control program continues, although the restoration of suitable
> >breeding habitat for Kirtland's Warblers may soon decrease or eliminate the
> >need for cowbird control.
> >
> >Wayne C. Weber
> >Delta, BC
> >contopus at telus.net