To me Brian that looks like what they call Gummy Cherry, I've got some of that wood and it will have dark lines and change color like that. Sometimes the grain is bright red, it dosen't effect the wood quality or the sound it produces, but it does give the call a little character. The Gummy Cherry seems to be a bit softer than regular cherry, and cuts very easy and sometimes splinters a bit.
WI Youth & LTH Mentor
Dodge Co. NWTF