The Ruby-throated hummingbird looks just like it sounds; it has a ruby colored throat, making it easily recognizable by hummingbird admirers everywhere.
The ruby-throat is the most common species that breeds in the eastern States and is most commonly seen by admirers as they are easily attracted to feeders by their inquisitive personalities. These birds will quickly become accustomed to human presence. If you plan to hang a feeder, these birds will sometimes become the main attraction and easily steal the show with their aggressive tactics. They will at times stay perched close by and defend their new found food source as others approach. They have also been known to swoop in and investigate red articles of clothing to make sure they aren't missing out on any food sources. These birds can be highly entertaining to watch.
The sex of the bird determines the rest of the coloring:
In adult males, they have an emerald green back, an iridescent ruby red gorget (throat) that may appear black under some lighting conditions, gray flanks, forked tail with no white. Smaller than the female.
Adult Females will have an emerald green back, a white breast and throat and a rounded tail with white tips. The adult female is the larger between the two sexes and it also has a longer bill.
Juvenile ruby throats of either sex look like the adult female. In August and September, the young males may develop some red spots in the gorget.
Molting occurs during the fall migration and continues into March. The young male will acquire full ruby gorgets during their first molt.