I remember sitting in the dark before dawn near some feeders in southeastern Arizona two years ago, just to catch a glimpse of a rare visitor to the area, the Streak-backed Oriole. After 3 hours we did catch just a brief glimpse of “the bird” (there was only one). Now two years later, I find they are common in this part of Mexico, and seem to like to enrich their fruit diet with a few flowers (perhaps containing nectar) plucked from various vegetation.
Like most Orioles, males of the Streak-backed variety are the most colorful, with females being considerably duller and less orange. However, the species ranges from northern Mexico (occasionally venturing into southern Arizona) where the two sexes are completely different in color, through most of Central America, where the two sexes become more and more similar in coloration going south.
Why would there be such a difference between coloration of females from the northern vs southern extent of their range?
Apparently, Streak-backed Orioles maintain permanent territories year-round in the southern part of their range, where the bright coloration of the females helps territory defense. In more northerly areas, the orioles maintain only a breeding territory, and may undergo short migrations away during the non-breeding season!