This very small little bird that I encountered a few times at the resort is called a Bananaquit. I mostly found them hanging around in the morning low in the bushes or near flowers, where they fed from.
These birds can be found on many of the islands in the West Indies as well as South America.
Many times, they behaved much like black-capped chickadees around here – very curious and not afraid to get in extra close to take a peek at what I was doing. They are quite acrobatic too, hanging upside down to get into flowers.
Bananaquit (Click Photos to Enlarge)