Nice capture! I like the angle of the bird swooping in toward the flower. The green stem in the background distracts - removing it and having just the dark background with mottled bits of green would make the bird "pop" better.
Nicely captures the challenge theme. Technically excellent photo and I'm sure it was difficult to capture. Addition of the hummingbird is a nice touch and having it dark against the dark background was a subtle choice. Perhaps too subtle, since it's pretty dark on my monitor.
Nice capture! It all works very well except the right side. There I'd recommend cropping out the brown bud and just a bit more. You may want to crop the same amount from the left side behind the hummer. Exposure is right on. Excellent choice of shutter speed.