Scientific name: Archilochus colubris
The only regularly breeding hummingbird in eastern North America, the Ruby-throated Hummingbird breeds west to about the 100th meridian. The tiny Ruby-throated Hummingbird puts on a great deal of weight after nesting, because a large amount of energy is needed for its southbound migration, which often takes it across the Gulf of Mexico.
Male Ruby-throated Hummingbirds are very territorial during the breeding season, but can also be aggressive in defending a food source such as a hummingbird feeder during migration. The only known record of nest parasitism by the Brown-headed Cowbird involved one egg that took up all of the room in the tiny hummingbird nest. The oldest known Ruby-throated Hummingbird was nine years old.