Hi Kaufman Field Guide to Advanced Birding is an excellent guide. There is over 30 pages devoted to just the 8 most challenging hummingbird species. Also a few years ago John Vanderpole published an excellent video guide, along with John Dunn, on North American Hummingbirds
Cheers, Bob Righter Denver, CO -- You received this message because you are subscribed to the Google Groups "Colorado Birds" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. To view this discussion on the web visit https://groups.google.com/d/msgid/cobirds/9E734FD3-BE10-40FF-960D-575E97DD2CCA%40earthlink.net.
