Date: 7/31/19 7:28 am From: <clearwater...> Subject: [obol] Re: Titmouse Oak or Juniper?
P.S. I finally found Kevin Spencer's discussion, down near the bottom of the daily digest, which brought up up the Cicero (1996) paper.
What Kevin wrote regarding titmice in the Klamath Basin makes sense to me. I've always been a little skeptical of Juniper Titmouse reports from Klamath Falls. At one time (early 2000s) we used to see reports from field trippers who thought they were seeing Oak Titmouse and Juniper Titmouse side by side in a couple of locations around K Falls. Those reports always seemed a little overly hopeful for me.
The Modoc Plateau just southwest of K Falls in California is more of a biological link than a barrier, as is the Cascade-Siskiyou area just north of the border.
But as you go east from there to Lakeview and beyond, desert basins start to act as barriers for tree-dependent species.
When you go over the Warner Mountains into the Cedarville/Ft. Bidwell/Adel area, you pass through conifer forest, particularly on the California (southern) end of the range. The forest habitat along the crest of this range isn't where you'd expect to find either titmouse species. So there's not much opportunity for gene flow across this divide, particularly for such sedentary species.
East of there you run into more and more desert basins (the Alkali Lakes east of Cedarville, Calcutta Lake north of there, etc.) that would inhibit east-west gene flow. Conversely, there are strips of junipers running north-to-south all through this area.
So there are plenty of reasons to expect Juniper Titmouse in this part of the Great Basin -- and very few reasons if any reasons to expect Oak Titmouse, or even hybrids.