Unlike Robber Flies, this fly mimic, falls in the Syrphidae family along with the tiny flower flies that visit flowers. This particular syrphid fly, Eristalis flavipes behaves like a Bumble Bee, buzzing while flying and nectaring on flowers.
My first clue that this was a fly was the short antenna. Bumble Bees have much longer antenna. The other clue was that the black and yellow coloration did not match any of my bumble bee guides.