Jeff's great images strongly suggest that the "Brewster's" Warbler is a very rare F2 backcross (4 reported instances at the time of publication of Peterson's guide) or a bird that has resulted from the mating between two F1 hybrids (Golden-winged x Blue-winged Warbler).
See picture in Peterson's "Field Guide to Warblers", p. 141. or google "f2 backcross Brewster's Warbler" on the Web. Paula Hansley Louisville -- You received this message because you are subscribed to the Google Groups "Colorado Birds" group. To post to this group, send email to [email protected]. To unsubscribe from this group, send email to [email protected]. For more options, visit https://groups.google.com/groups/opt_out.
