Owl team response to population decline question

Owl team response to population decline question by Kim_Ingram, at 1:25 p.m. on 3 November 2011,

Dear Ms. Dobrovolny:

At the annual SNAMP meeting, I explicitly stated that I did not know what is causing this recent (past 10 years) owl decline. Our research suggests that the decline is real based on two different estimators producing the same result. I was also asked by a participant at the meeting if fuel treatments might be the cause of the decline and I said that I did not know because there were other factors that might be involved such as clear cutting on private land. By logical extension, this would apply to home development as well, as you suggested in your letter. Recall that the owl component of Last Chance includes the entire Eldorado spotted owl density study area, which encompasses a much larger area than Last Chance and has many more owl territories. Because of the uncertainty about the cause of the decline, the owl team has proposed a retrospective study to examine all observable changes in owl habitat that were due to disturbance. Presumably this would allow us to account for different types of disturbance, which would address one of your concerns. Our inference would be restricted to our study areas because we are not measuring change or monitoring owls throughout Eldorado County although our study areas might be a representative sample of this population. In addition, because of severe budget limitations, I doubt that our study could be expanded to include all of Eldorado County.


R. J. Gutierrez, Professor and Gordon Gullion Endowed Chair in Forest Wildlife Research

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