The Collaborative International Dictionary of English v.0.48:

Rubythroat \Ru"by*throat`\, n. (Zool.)
   Any one of numerous species of humming birds belonging to
   Trochilus, Calypte, Stellula, and allies, in which the
   male has on the throat a brilliant patch of red feathers
   having metallic reflections; esp., the common humming bird of
   the Eastern United States (Trochilus colubris).
   [1913 Webster]