Sunday 29 May 2016

[cobirds] RFI -- Red Crossbills and spruce

All,

I'm writing (yet again) to solicit information regarding the whereabouts of large concentrations of crossbills and spruce cones.

This summer/fall I'm hoping to do fieldwork that will compare reproductive isolation between types 2 and 5 during a large Engelmann/blue spruce cone crop to reproductive isolation when crossbills are predominately utilizing their respective "key conifers" (in this case, ponderosa and lodgepole pine). Although types 2 and 5 seem to be adapted for foraging on ponderosa and lodgepole, respectively, they will converge in their use of spruce when available, given that spruce seeds are easily accessible by both call types. One of the main projects I'm working on for my PhD is to try and understand how these fluctuations in resource availability might influence the extent of interbreeding between call types.

If you happen to notice any spruce forests with a large amount of developing cones, I would greatly appreciate hearing about it. If there are developing cones, they should be detectable already (as small pink/purple cones).

There are good numbers of type 2 along the Front Range foothills that should be on the move in search of developing cone crops soon (the type 2 that bred on ponderosa in the Laramie Range this winter have already moved on). One possibility is that they'll start moving to higher elevations where they could come into contact with a large spruce crop and type 5, which could make for a very interesting late summer/early fall breeding season.

Good birding,
-Cody Porter
Laramie, WY

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