Ruby-Throated Hummingbird Fact Sheet

Signs of the Seasons observers are contributing phenology data to monitor for possible changes in the timing of hummingbirds’ annual life cycle events in response to a changing climate.

If you see a hummingbird in your yard or garden, it is most likely to be a Ruby-throated hummingbird. They are the only hummingbird regularly found from May into September east of the Mississippi. These tiny birds, only 3 to 4 inches long and weighing 2 to 6 grams, migrate north from central America and Mexico every spring to breed throughout the US and parts of Canada. They usually arrive in Maine sometime in May.

Appearance: Easy to identify by their small size and precise flight behavior the Ruby-throated hummingbird has a metallic green head and back, white breast, tail feathers and a long, needle-like bill. The male has a distinctive iridescent red throat (which at certain angles can appear to be black). The female does not have a red throat and her outer tail feathers have white tips. The juvenile resembles the female.

Feeding: The Ruby-throated hummingbird has an extremely rapid metabolic rate. Their hearts beat more than 600 times per minute, and their tiny wings can beat up to 70 times per second during regular flight, and faster during display behaviors, creating a characteristic buzzing sound that also makes them easy to identify. They can even fly backwards! This maneuverability in flight helps them obtain nectar, which they do while hovering in position, and catch insects. Ruby-throated hummingbirds eat 5-6 times each hour to maintain their high metabolic rate. They prefer tubular flowers that are red or orange in color. When nectar is not available, they may eat tree sap.

Life Cycle: Ruby-throated hummingbirds are solitary, and will migrate alone. Males typically arrive in Maine before females. Extremely territorial, the males will aggressively establish and protect a small area of nectar sources as their own, chasing off insects and other hummingbirds that dare to approach. You may witness some amusing acrobatic air shows when two hummingbirds are vying for the same feeder or area of a garden. Females build nests and raise their young on their own. Nests are built on tree branches or in shrubs, from a variety of materials held together with spider silk. Two or three eggs are laid and incubated until they hatch about 2 weeks later. Offspring then remain in the nest for another 3 weeks. Females will have, at the most, two broods each season. As fall approaches, hummingbirds intensify their feeding to build up fat deposits for the long trip back to Mexico or Central America. They also feed frequently along the migration route. A typical hummingbird will live about 5 years, but individuals have been known to live up to 12 years.

Sources and Additional Information:

USA Phenology Network – Observing Plants and Animals, http://www.usanpn.org/Archilochus_colubris

UMaine Cooperative Extension Bulletin # 7152, Understanding Ruby-Throated Hummingbirds and Enhancing Their Habitat in Maine

USDA National Resources Conservation Service and Wildlife Habitat Council, Fish and Wildlife Habitat Management Leaflet Number 14, December 1999, http://plants.usda.gov/pollinators/Ruby-throated_hummingbird.pdf

US Forest Service, Celebrating Wildflowers: Ruby-Throated Hummingbird, http://www.fs.fed.us/wildflowers/pollinators/pollinator-of-the-month/ruby-throated_hummingbird.shtml

US Fish and Wildlife Service National Digital Library, http://digitalmedia.fws.gov/index.php