Just a short note. Yes, it is true that Black Merlins typically have less distinct tail bands than the other races (Taiga and Prairie). However, many Black Merlins can have quite distinct whitish tail bands, and Taiga Merlins can have limited or no tail bands at all. Like I always say (and have in print) "almost no field mark is 100% reliable."

Check out the Taiga Merlins above, the bird on the left (adult female) has a distinctly whitish-banded tail, the bird in the middle (juvenile) has limited tail bands, and the bird on the right (juvenile) lacks tail bands altogether. Note that most Merlins of all races do have a darker tip.