You know the weird thing about a hummingbird robot, is that at this stage, it might be easier to get a camera and transmitter, and train a real hummingbird.  At least if it is in danger, a real hummingbird would fly somewhere else, not sure about the robot, the real hummingbird will last longer, and probably fly much more .. stealthily…

Alternates…

Find a way to transmit the visual cortex signals of a real hummingbird to ground… then train the hummingbird.

Find another hovering bird, which is smarter and more trainable than the hummingbird..

Make a robot to follow the hummingbird at a distance… with the camera on the hummingbird etc..