Wildlife Profile


Ruby-throated Hummingbird (Archilochus colubris)
by Mark Johns

Wild Facts about the Ruby-throated Hummingbird

The Ruby-throated Hummingbird is eastern North America’s only species of breeding hummingbird, and a common summer inhabitant of woods, parks, and gardens from central Canada to the Gulf Coast. Hummingbirds are perhaps our most unique birds, capable of flying faster than 30 m.p.h., more maneuverable than helicopters and about the weight of a penny. Hummingbirds as a group are found only in the Americas, with about 325 total species that mostly live in the tropics. Seventeen species occur in the United States, and thirteen breed here. In recent years, other hummingbird species are being reported in North Carolina during winter, with five species detected as of the late 1990’s. However, the only breeding hummingbird of North Carolina is the Ruby-throated Hummingbird, which is at best a rare winter straggler in our region.

History and Status

This species is found throughout the state as a breeder, usually arriving in our region

in late March and early April each spring. It is a neotropical migrant that winters mostly

in Mexico and Central America. Neotropical (New World) migratory birds breed during summer in temperate North America, migrating north each spring from wintering areas, then fly back south to spend the bulk of the year in Mexico, Central or South America, or the Caribbean

In geographic area, this species occupies the largest breeding range of any North American hummingbird. Its western distribution conforms closely with the range of eastern deciduous and mixed forests. A recent increase in birds overwintering in lower Florida and along the Gulf Coast may be partly due to the increase in exotic plantings and abundance of feeders. On the whole, evaluation of density is difficult and more study is needed. Breeding Bird Survey (BBS) data suggest that populations are stable or increasing, but these data should be interpreted with caution since detection may be biased toward territorial males. For now, this bird seems to be doing well in our state.

Description

Ruby-throated Hummingbirds are iridescent green with a long slender bill. Adult males have a red throat patch that is absent in females and immature birds. The shiny throat feathers of the adult male, called a gorget, are the result of iridescence. In certain light, the colors glisten like the film on soap bubbles, but at other times simply appear black. The female has a blunter tail with white spots along the edges, while the male has a somewhat notched tail that is black along the sides with no or little white spotting. Some older females may develop a few red feathers on their throat, and immature males may have dusky streaks on their throat in addition to a few metallic red feathers.

Habitat and Habits

Adult Ruby-throated Hummingbirds only weigh about 3-4 grams on average. This tiny size doesn’t stop many of these birds from flying nonstop across the Gulf of Mexico during both spring and fall migration. To accomplish this over 500 mile flight, individuals often double their body mass by gorging on nectar and small arthropods before departure. However, the migratory routes of this bird remain rather poorly documented, and some may follow a coastal route south during fall migration.

These birds usually breed in mixed woodlands and eastern deciduous forest, but also associate with woodland clearings, gardens and orchards. In our region, they also nest regularly in pine and mixed pine situations. These birds are highly territorial during the breeding season, with the male’s territory often centered on a food source when sufficient cover is available. Interestingly enough, if food is plentiful breeding males may occupy territories only 50 feet apart.

There is no pair bond for this species during the breeding season, as the male and female remain together only long enough for courtship and mating. Males display for a female when she enters his territory, and the climax of this is usually a series of U-shaped looping dives above the female that gradually shift to a series of fast, side-to-side horizontal arcs. After mating, the female alone selects a nest site that is usually near the tip of a downsloping branch with openness below and a leaf canopy above.

The nest is sometimes near or directly above water, and is sometimes found in odd places like on loops of chains, wire and extension cords. The nest height ranges between 1 to 60 feet off the ground, with an average of about 15 feet. Females alone build the nest in about 6 to 10 days that is covered with lichens. This tiny cup of wadded plant down is bound with spider webbing, and is only about 1-2 inches high and 1.5 inches wide.

This bird is a daytime feeder. Floral nectar and small insects and spiders are the main food, with tree sap also taken when nectar is scarce. This bird prefers, but is not limited to, red tubular flowers as a nectar source. Some native favorites include: coral honeysuckle, trumpet creeper, wild bergamot, cardinal flower, buckeye, jewelweed, columbine, fire-pink and crossvine. These are all excellent choices to establish in your backyard to attract hummingbirds, as well as properly stocked and cleaned hummingbird feeders. The vine trumpet creeper appears to be primarily adapted to pollination by Ruby-throated hummingbirds. This bird also plays an important role in the seed setting patterns of cardinal flower, in preventing the hybridization of bee-balms and in pollination of jewelweed.

Range and Distribution

This hummingbird breeds throughout the eastern United States, and extends into parts of southern and western Canada. It winters in portions of lower Mexico and throughout much of Central America. Wintering individuals are also found in southern Louisiana and Florida on a regular basis, and a few successful overwintering records exist for Alabama and Georgia. Females have been documented to live at least 9 years, and males at least five years.

People Interactions

Although artificial feeders are sometimes blamed for delaying migration in Ruby-throated Hummingbirds, there is no evidence to support this. The natural urge to migrate (which is triggered by day length and is dependent on complex biochemical changes) is too powerful for the presence of feeders to make a serious impact. In fact, leaving feeders up in our region may be of benefit to the increasing numbers of western hummingbird species that are now being found in winter. Plantings of hummingbird flowers in gardens may improve breeding habitat, but this needs verification. Some predation from house cats has been noted at feeders, and collisions with windows in urban/suburban area occurs. Effects of pesticides on foraging birds needs study. All in all, this is probably the most beloved bird in our state, and certainly its return each spring to backyard feeders is widely celebrated.

Suggested Reading

Hummingbirds of North America by True, 1993, Univ. of New Mexico Press

How to Attract Hummingbirds and Butterflies by Ortho Books, 1991,Chevron Comp.

Enjoying Hummingbirds More by Bird Watcher’s Digest, 1992, Bird Watcher’s Digest Press

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