[Tweeters] Re: Barred Owl Kill-off (proposed plan)
rrpearson at centurytel.net
rrpearson at centurytel.net
Sat Jul 27 20:13:43 PDT 2013
These are good questions and one should always know as many facts as possible. There is a wealth of data and information for Spotted Owls, possibly more than for any other species, but it is not easy to wade through. I’ll try to provide information that arrives from my experience that may help inform opinion. I have been tracking Spotted Owls on the Cowlitz Valley Ranger District, Gifford Pinchot NF since 1991, and was one of the first anywhere to begin tracking and looking specifically for Barred Owls to see what their impact might be on Spotted Owls.
The Spotted Owl was listed as a threatened species in large part because of the projected continued logging of old-growth forest. The largest reservoir of Spotted Owl sites was on Forest Service land, and the management intent was to treat most of the forest there similarly to private land: cut down all the big trees and replace them with ‘young, vigorous growth’ – tree plantations. The FS land reserved from logging was mostly high elevation and not very useful in retaining Spotted Owls or any other of the many species dependent on old-growth forest. So if the intent was to convert most old-growth forest to tree plantations, and Spotted Owls depended on old-growth forest, it was easy to see what the outcome would be.
The impact of logging habitat could most clearly be seen in a comparison of Federal land to private land. In the 1990s, SW Washington west of I-5, which had mostly been logged, had only a handful of active Spotted Owl sites. My area directly west still had approximately 150 active Spotted Owl sites. The land area was approximately equal. Clearly, logging old forest had a negative impact on Spotted Owls.
When the NW Forest Plan went into effect in 1994, Spotted Owls in my area were still doing very well. Logging had reduced habitat nearly everywhere, but in most places not to the point where Spotted Owls could not function. 1992 was a banner year for Spotted Owls in that most sites reproduced that year, and nearly every historical site had Spotted Owls present. 1994 was nearly as good. Detections of Barred Owls were increasing but without any observable effect on Spotted Owl sites. In those years, judging from available habitat and what had been logged, Spotted Owl site numbers were pretty close to what the number would have been without any logging. Continued logging of habitat would have begun to seriously reduce numbers, but it had stopped in time to adequately support most of the Spotted Owl sites that remained if there was no further logging of habitat.
Barred owls were first found in my area in 1978, the same year the first Spotted Owl surveys were conducted. There were 2 male Barred Owls found, both at low elevation in a marshy area south of Randle. Through the 1980s and 1990s Barred Owl numbers slowly increased and didn’t have any observable effect on Spotted Owls. The 2000s were different.
Through the 2000s Barred Owl numbers began to steadily increase yearly while Spotted Owl numbers decreased simultaneously. Graphing the number of sites found active for both species through these years results in nearly perfectly mirrored lines of increase for Barred Owls and decrease for Spotted Owls. During this time no additional habitat was logged, indicating the decrease in Spotted Owl numbers was due to Barred Owl presence (but some qualification later). There may have been some lag effect to habitat reduction, in that some Spotted Owl sites may have eventually gone inactive because of reduced habitat, but if there was, that was overwhelmed by the evidence of simultaneous and mirrored Barred Owl increase and Spotted Owl decrease.
Additionally, as the 2000s progressed, I increasingly began to find Barred Owls where I used to find Spotted Owls. By 2005, the number of active Barred Owl sites equaled the number of historical Spotted Owl sites. In 2006, Barred Owl sites surpassed Spotted Owl sites. Currently in 2013, there are 254 active Barred Owl sites compared to 159 historical Spotted Owl sites. Over the last 5 years, I have found Spotted Owls at only 79 sites, or just over half of the historical sites still active. My estimate, in the 30 years from the high-water year of 1992 to present, is that the active Spotted Owl sites have decreased to at most 40% of what there was in 1992, with little additional loss of habitat but a great increase in Barred Owls.
Maybe the best way to asses the impact of Barred Owls is to compare National Parks, where there has been no habitat reduction, to other areas that have had logging. The National Parks have seen a dramatic increase in Barred Owls similar to all other areas, and have also seen Spotted Owl numbers decline rapidly during this time. While there may be other reasons for Spotted Owl decline in the NPs, and it’s possible that Spotted Owls declining for other reasons have made it easier for Barred Owls to establish themselves, the relationship of simultaneous Barred Owl increase and Spotted Owl decrease remains and is similar to other areas. Without any habitat loss, Spotted Owls still have declined where Barred Owls have increased.
However, there is one important difference. In SW Washington, where logging of habitat has continued, the Spotted Owl is now considered to be extinct. For both Mt. Rainer and Olympic NPs, Spotted Owls are still active, although at reduced numbers, while the areas adjacent to the parks that have had habitat heavily logged have seen the Spotted Owls reduced to nearly nothing.
To me, there appears to be a connection between the amount of available habitat, the number of Barred Owls, and the number of Spotted Owl sites that remain active. Barred Owls can withstand, and may even benefit from, logging. The area in SW Washington where Spotted Owls are now considered extinct and has been nearly all logged in the past also has the highest concentration of Barred Owls of any place I’m familiar with. The logging that was detrimental to Spotted Owls has appeared to be beneficial to Barred Owls. The qualification I mentioned above is that while Barred Owls have a negative impact on Spotted Owls, the impact is greater where there has also been logging in the past, so that the combination of logging and Barred Owls has more of an impact than either by itself. That, I think, is the key.
I don’t have answers, and it may be that even in the unlogged areas Spotted Owls will eventually be replaced and are doomed in the Pacific NW no matter what we do. But it is also pretty complex, and comparing to other species or efforts at recovery is not perfectly predictive. No one really knows what will happen if we do this or that, or nothing.
I like Barred Owls. I have spent the last 6 years recording their vocalizations as a research project. I can take someone to any of over 400 pairs I am familiar with. At the same time Spotted Owls are amazing birds, and I hope that anyone who has not had the pleasure of seeing them up close in their natural habitat will get the opportunity to do so. They are worth the effort to retain if there is anything we can do to help them. I hope what I’ve written here will help inform some opinions in a difficult matter.
rrpearson at centurytel.net
Date: Sat, 27 Jul 2013 11:47:06 -0700
From: Ronda Stark <rondastark18 at gmail.com>
Subject: Re: [Tweeters] Re: Barred Owl Kill-off (proposed plan)
To: Barbara Deihl <barbdeihl at comcast.net>
Cc: Tweeters at u.washington.edu
<CAFNywYXeMU15geeghEftZGP5-5zqTDSruvvgo3DmjzNkMKha_w at mail.gmail.com>
Content-Type: text/plain; charset="iso-8859-1"
Its ok to have dialogue as long as we all know the facts. What percentage
of spotted owl decline is directly attributed to presence of barred owl?
Is this percentage derived from sound science or just a wild guess? What
percentage of decline is due to habitat loss? Wasn't spotted owl endangered
before barred owl showed up on the scene?
Eradication, or partial eradication, of one specie, in preference of
another specie, is not something that has been sanctioned in the past. Are
we setting new and possibly dangerous precedent?
On Fri, Jul 26, 2013 at 2:36 PM, Barbara Deihl <barbdeihl at comcast.net>wrote:
> Oh, it'll probably happen - always some human fallibility present in every
> On Jul 26, 2013, at 1:39 PM, ck park wrote:
> one can hope a spotty won't accidentally be shot or otherwise killed
> during such a cull... oh, the irony...
> 00 caren
> george davis creek, north fork
> On Fri, Jul 26, 2013 at 1:21 PM, Barbara Deihl <barbdeihl at comcast.net>wrote:
>> We can't have it all - unlimited human population, unlimited human
>> consumption of habitat and proliferation of the entire diversity of
>> wildlife. We can only try to temper our insatiable need to have and
>> control every aspect of and every speck of life and resources on this
>> planet, and do this through continued experimentation, analysis of the
>> results and willingness to change our thoughts and plans in accordance.
>> I'm inclined to think that we need to buy a little time with some
>> strategic reduction of some Barred Owls, not only to see how the Spotted
>> Owl fares, but also to see if it makes a difference in population numbers
>> of other birds and animals that the Barred Owl also affects, (example:
>> Western Screech Owl that it preys on).
>> I appreciate all those who have and still will participate in this
>> discussion - it's nice to get some new material to help me formulate my
>> latest thoughts on this subject (which actually comprises a multitude of
>> Once again, the Tweeters forum stimulates some brain cells...:-)
>> Barb Deihl
>> North Matthews Beach - NE Seattle
>> barbdeihl at comcast.net
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