Ruby-throated Hummingbird

Ruby-throated Hummingbird, Archilochus colubris, is a species of hummingbird that breeds in eastern and central North America.

Description
Tiny 7.5 - 9 cm, iridescent green bird with a black throat patch that reflects bright ruby red in the sun. Female is similar but lacks the throat patch. Juveniles are similar to females.

Similar species
Separating female and immature Black-chinned Hummingbirds from Ruby-throated Hummingbirds can be difficult (Tyler, 2005), and depends on a detailed study of individual primaries and rectrices (Pyle 1997), as cited in Butler, et al. (2007).