Here are some general principles concerning injured hummingbirds which you should know. This information is provided by the Hummingbird Society.
Hummingbirds fed on a diet of sugar-water alone will die, and full-nutrition formula for them is not available to the general public. You must seek competent, licensed help to assure a bird’s survival, and you must do it quickly.
It is illegal, a felony offense in the U.S., to keep a hummingbird in captivity, and it is also illegal to have possession of a nest or any part of the bird (such as a feather). As a result, the hummingbird should be transferred to a rehabilitator.
Mother hummingbirds rarely abandon a nest, although it can and does happen. Never assume that abandonment has occurred. To be certain whether this has occurred or not, you must watch continuously for at least an hour, sometimes more, to be sure she is not returning. In general, if the chicks look healthy, the mother is taking good care of them. Feedings can be extremely quick and surprisingly infrequent in some stages of the chick’s development.
While it is not very likely that you will encounter an injured hummingbird, I hope that you will find this information useful in the event that you should ever need it. If you have ever encountered an injured hummingbird, please share your story with us.