not difficult photography if you can find sufficient light...I don't use flash (don't like that look).
many lodges in Ecuador (and nearby countries) have hummingbird feeders; they create an unnatural situation (so many hummers in one area), and no one knows what a "canned" sugar diet does to the birds (it could be harmless as sugar is sugar whether from a flower or from packaged sugar). Anyway, since these feeding stations are so popular with tour groups (birders), no one minds...and as a photographer, it certainly makes getting images of these birds a heck of lot easier...anyway, though hummers have lots of colors, that does not necessarily make a good color photo...
all images with Canon 5Ds and 400mm F2.8 II, sometimes with the 1.4x III TC.
ISO 400-800.