I'm a coffee drinker, but not a coffee connoisseur, so I'm a little hesitant to add to the conversation. But, I did want to point out that there is a "gold standard" in bird-friendly coffee, which is certification through the Smithsonian (based on 11 criteria developed through the Smithsonian's Migratory Bird Research Center. I've talked to a number of coffee farmers who grow shade coffee that is not certified and they have a number of reasons for not going the certification route. There is a cost to certification, which some growers can't afford. And, there are some farmers who have a ready market for their shade coffee such that certification isn't helpful in generating new sales or markets.
There are lots of great resources to read more about bird friendly coffee - ABA just put out a nice article in Birding which outlines some of the issues with certification, and goes into some detail about organic (required for bird friendly certification) and fair trade certifications which may be of interest to some birders.