The ruby throated hummingbird (Archilochus colubris) is one of the most widespread and familiar hummingbird species in North America. With its metallic green upperparts, brilliant ruby red throat (in the male), and diminutive size, the ruby throated hummingbird is easily recognizable. Despite its small stature, the ruby throat plays an important role in its ecosystem as a pollinator and prey species.
Physical Characteristics
The ruby throated hummingbird measures between 2.8-3.5 inches in length and has a 3.1-4.3 inch wingspan. They weigh only 2-6 grams. As mentioned above, the males have vibrant metallic emerald green upperparts and a ruby red throat (gorget). The females lack the red throat patch and are more drab colored with green upperparts and white underparts. Both sexes have forked tails. The long, slender bill of the ruby throat allows it access to nectar at the base of long tubular flowers. Their wings beat up to 53 times per second, allowing them to hover in place and fly in any direction including upside down or backwards. This maneuverability allows them to access flower nectar that other pollinators may not be able to reach.
Habitat and Range
The ruby throated hummingbird has the largest breeding range of any hummingbird in North America. Its breeding habitat extends across most of eastern North America from Nova Scotia west to the Dakotas and south to the Gulf Coast. The species winters in Central America and Mexico. Preferred habitat includes meadows and forest edges with flowering plants. They are also common in parks and gardens, especially where nectar feeders are present.
Migration
One of the most incredible facts about the tiny ruby throated hummingbird is its migratory habits. The ruby throat makes an arduous round trip migratory journey each year between its breeding and wintering grounds. In fall, they migrate south across the Gulf of Mexico, flying 500 miles nonstop over open water. This feat is especially astonishing when you consider a 500 mile trip would be equivalent to a human running 4 million consecutive marathons. In spring, they make the same journey in reverse, fueled by flower nectar and tiny insects along the way. Some research suggests the species may navigate by sensing the earth’s magnetic field.
Diet
Like all hummingbirds, ruby throats have very high metabolisms. To support their energy needs, they feed on flower nectar and small insects and spiders. Their long, slender bill and extendable tongue allows them to retrieve nectar from tubular flowers. Some favorite nectar sources are bee balm, cardinal flower, trumpet creeper, and salvia. The ruby throat prefers red-colored tubular flowers, which are favored by fewer competing pollinators compared to blue or yellow flowers. To obtain protein, they capture small insects and spiders from flowers, trees, shrubs, and even snatch them out of spider webs. They may eat up to half their weight in insects each day. A few favorite insect prey include mosquitoes, fruit flies, gnats, aphids, and spiderss.
Reproduction
The reproduction of ruby throated hummingbirds begins in spring when the birds have returned from migration. Males establish breeding territories centered around nectar sources to attract females. Their aerial displays and aggressive defense of territories is one way they court females. Once paired, the female builds a tiny cup-shaped nest out of plant down, spider silk, and lichen on the branch of a tree or shrub. The inside of the nest is lined with soft plant fibers. She lays just two pea-sized white eggs and incubates them for 12-14 days. Ruby throat nests are only 1.5 inches across; an incredible feat of engineering allows the nest to expand as the chicks grow. The chicks hatch with eyes sealed shut and barely any feathers. They are fed regurgitated nectar and insects by the female and fledge from the nest in 16-18 days from hatching. The first brood departs the nest in late May-July, and females may raise 1-2 broods per summer. Males do not assist with nesting or feeding the young.
Ecosystem Services
Despite its tiny size, the ruby throated hummingbird provides valuable services to its ecosystem. Here are some of its contributions:
- Pollination: The ruby throat is the primary pollinator for many flowering plant species. As it visits multiple flowers to feed on nectar, pollen grains stick to its bill and head and are transferred to the next blossom, resulting in pollination. Some flowers even depend on the ruby throat specifically for pollination.
- Insect population control: By feeding on small insects like mosquitoes and aphids, the ruby throat helps control populations of harmful insects. They may eat up to thousands of insects per day.
- Seed dispersal: Nectar and pollen that stick to the hummingbird’s bill and head is carried to the next flower, resulting in pollination. When pollination is successful, it allows plants to produce fruits and seeds. By transporting pollen, the ruby throat facilitates seed dispersal and the spread of native plants.
- Indicators of stopover habitat quality: Since ruby throats migrate through the same stopover habitats each year, tracking their numbers in these areas provides a barometer of habitat quality and how well the stopover sites support migrating bird populations overall.
- Aesthetic value: In gardens, parks, and backyards, ruby throated hummingbirds provide enjoyment and entertainment while feeding at nectar feeders or visiting flowers.
Threats and Conservation
Overall, ruby throated hummingbird populations are still abundant, and they are classified as Least Concern on the IUCN Red List. However, there are some potential threats to their populations:
- Habitat loss from human development
- Pesticide use reducing insect prey populations
- Invasive plant species displacing native nectar plants
- Climate change effects on migration and flower/nectar availability
Some conservation practices that can benefit ruby throated hummingbirds include:
- Preserving intact forests and meadows with native flowering plants
- Landscaping with native plants, especially tubular red flowers
- Avoiding use of pesticides
- Providing clean nectar feeders especially during migration
- Participating in citizen science monitoring programs such as the Hummingbird Migration Celebration
With a few simple actions by homeowners, gardeners, and land managers, the ruby throated hummingbird’s vital ecosystem services can continue sustainably into the future. This tiny migratory bird has an outsized role in its environment; maintaining healthy populations ensures proper functioning of the broader eastern North American ecosystems it inhabits.
Conclusion
Despite its tiny stature, the ruby throated hummingbird plays an integral role in its ecosystem as a major pollinator for wildflowers, disperser of native plant seeds, controller of insect pests, and indicator of migratory stopover habitat quality. This migratory species provides essential ecosystem services across its breeding range in eastern North America through its interactions with flowering plants and insects. While currently abundant, some threats like habitat loss and pesticides could impact ruby throat populations. However, we can help conserve the species through actions like planting native flowers and reducing pesticide usage. The ruby throated hummingbird is a fascinating species that warrants our admiration and stewardship for the health of eastern North American ecosystems.
