Genetic variation within the bird kind, then reproductive isolation.
Whoa! "the bird kind?" All birds represent a single created kind? So a hummingbird, an ostrich and a penguin are all related by common ancestry!? But humans and apes aren't?!
45 posted on 11/22/2009 5:58:43 AM PST by Stultis
(Oceania has always been at war with Eastasia; Democrats always opposed waterboarding as torture)