By Rebecca Thompson, Manager of Academic Programs
Small, but sweet and filled with life, Arcilochus colubris, or ruby-throated hummingbirds, are but one of the magnificent aerial wonders visitors can discover at Holden Forests & Gardens (HF&G). Native to open, deciduous woodlands of eastern North America, these birds are typically seen flying acrobatically around forest edges, old fields, orchards, parks, gardens and backyards. They have unique physical adaptations in their bones and muscles, which allow them to fly straight up, straight down, backward and forward. They can also hover for long periods of time and perform aerobatics such as backward somersaults.
Ruby-throated hummingbirds’ primary food source is nectar. They lap up nectar with their tongues rather than using their beaks for straws. They can lick ten to fifteen times per second while feeding. They are particularly fond of tubular red or orange flowers, such as the cardinal flower, coral honeysuckle, jewelweed, bee balm, columbine and red buckeye. They are omnivores, sometimes feeding on insects and spiders. They can catch insects such as mosquitoes, gnats, fruit flies and bees in midair or pull them out of spiderwebs. Ruby-throated hummingbirds also forage for insects attracted to oozing sap from trees or by capturing small caterpillars and aphids from leaves.
Ruby-throated hummingbirds are the only species of hummingbirds to breed in eastern North America. Once males establish a territory, they court females with signature fluttering sounds while flying, diving and showing off their red throat. They usually mate with more than one female during breeding season. When mating season is over, female ruby-throated hummingbirds do not interact with the males.
Females build nests in deciduous trees such as oaks, birches and poplars. Occasionally, they build nests in pine trees. Nests are constructed in five to six days, ten to forty feet above ground on downward sloping, forked slender branches. Nests are two inches across and one inch deep. They are made of thistle or dandelion down held together with strands of spider silk. The outside of the nest is camouflaged by lichen and moss.
In early June, female ruby-throated hummingbirds lay two elliptical white eggs about the size of a navy bean. Females incubate the eggs for about sixteen days before tending to their young. The young hummingbirds fledge the nest in nineteen to twenty-two days. Females usually have one to two sets of young per breeding season. Females may begin building a second nest while still feeding young from the first nest.
According to the North American Breeding Bird Survey, ruby-throated hummingbird populations have increased every year
from 1966 to 2014. Partners in Flight estimates a global breeding population of twenty million. Hummingbird feeders have helped supplement ruby-throated hummingbirds’ diet. However, they can also create a problem for local populations if they are not maintained regularly and placed in proper locations away from house cats
Size: 2.8-3.5 inches
Wingspan: 3.1-4.3 inches
Description: Emerald back and crown, with gray or white underparts. Males have an iridescent red throat.
Range: Breed throughout eastern to midwestern North America, from southern Canada to the Gulf of Mexico; Winter in Mexico, Central America, Caribbean islands and a few remain in the Gulf states.
Voice: Males sing a constant series of monotonous chirps early in the day. Both sexes make high-pitch chirps and speak while in flight or being chased.
Best Location to View:
Holden Arboretum: Butterfly Garden and Wildflower Garden Botanical Garden: Pollinator Garden