As I struggle to learn to distiguish similar species in the field, I began
to wonder how they became separate in the first place. It seems obvious, for
example, that Long and Short-billed Dowitchers came from a common
ancestor. They overlap in range and appear to have similar ecologic niche.
So what happened in the past to split them into two distinct species? Any
thoughts?

Jack Stephens
jsteph02 at sprynet.com
Edmonds, WA