Are Rufous Hummingbirds rare?

Rufous Hummingbirds (Selasphorus rufus) are one of the most widespread hummingbird species in North America, with a breeding range extending from Alaska south to California and east to the Rocky Mountains. However, within their range, they are considered uncommon to rare during the breeding season in many areas. Their rarity is due to their specific habitat requirements and the challenges they face on their incredible migratory journeys. In this article, we’ll explore the factors that contribute to the scarcity of Rufous Hummingbirds across parts of their range.

Breeding Range and Abundance

Rufous Hummingbirds breed primarily in forested mountain areas of the western United States and Canada, with Alaska representing the northern limit of their breeding grounds. They are most abundant in the Pacific Northwest region.

In Alaska and northern Canada, Rufous Hummingbirds are considered uncommon breeders. Farther south in Canada’s British Columbia province and the northwestern U.S., they are locally common during summer. However, moving east along their breeding range, Rufous become increasingly sporadic and rare.

For example, in Montana they are considered a rare breeding species, found only locally in the western part of the state. They are also scarce and local nesters in the Black Hills of South Dakota. In the Rocky Mountains, they are uncommon and very local in summer.

On the southern end of their range, Rufous Hummingbirds breed uncommonly in higher elevation areas of California, Nevada, Utah, Colorado, Arizona and New Mexico. Overall, their relative rarity across this wide span of their breeding grounds is attributed to specific habitat requirements.

Habitat Requirements

Rufous Hummingbirds rely on mature coniferous forests, woodlands and riparian areas that provide sufficient flowers, insects, and nesting sites. They prefer areas with an abundance of nectar-producing flowers and nesting sites near meadow openings which provide foraging opportunities. Since they are migratory, availability of protein-rich insects to fuel their long journeys is also a habitat requirement.

The increasing fragmentation of mountain forest habitats due to human activities poses a threat to breeding Rufous Hummingbirds. Loss of flower-rich meadows and disturbance of riparian areas further reduces habitat quality. Where human development encroaches on their specialized breeding habitat, Rufous Hummingbird numbers decline. Their reliance on certain habitat features makes them more vulnerable to decline across their breeding range.

Migration Challenges

The epic migratory journeys made by Rufous Hummingbirds also contribute to their relative rarity. They breed the furthest north of any hummingbird species, yet migrate astonishing distances to reach their wintering grounds.

Fall Migration

In late summer, Rufous Hummingbirds begin migrating south from their breeding grounds. They migrate down the Pacific Coast and also through the Rocky Mountains, wintering primarily in Mexico and the Gulf Coast region.

This migration covers 3,900-5,000 miles each way – the longest round-trip of any hummingbird species. The arduous fall journey lasts up to two months, involving travel through diverse terrain and habitats. Lack of dependable food sources along the migration route poses challenges and threats.

Rufous Hummingbirds require abundant nectar supplies to fuel their metabolically demanding flight. However, nectar availability and flower blooming cycles vary across latitudes and landscapes. The birds are challenged by locating reliable stopover sites to refuel along their route. Dwindling, fragmented habitat and expanding urbanization further threaten their migratory success.

Spring Migration

In spring, Rufous Hummingbirds begin the northward return trip as early as January. Competition for food resources is especially intense during this season, as many species migrate concurrently up the west coast.

The timing and abundance of flowering plants is more critical on the spring journey. Inclement weather such as snowstorms and cold snaps also endanger returning birds. Lack of fat reserves to endure such conditions causes mortality. Surviving such a lengthy and precarious migration likely takes a physical toll that impacts breeding success.

All these obstacles combine to whittle down their numbers, contributing to the Rufous Hummingbird’s generally uncommon to rare status across most of its breeding habitat. Successfully traversing thousands of miles twice annually makes their scarcity understandable. Their reliance on highly specific breeding and migratory habitats renders Rufous Hummingbirds vulnerable to population declines.

Population Trends

Despite the many threats they face, Rufous Hummingbird populations appear to be stable currently. According to the North American Breeding Bird Survey, Rufous Hummingbirds even showed a slight population increase from 1966 to 2015.

However, they are still considered Near Threatened on the IUCN Red List due to the many risks to their specialized habitats. There is concern that climate change could desynchronize flower blooming and nectar availability with periods of peak energy needs during migration. Continued monitoring is required to ensure Rufous Hummingbird populations remain stable.

West Coast

Along coastal California, Rufous Hummingbird numbers appear to be increasing locally, perhaps in relation to planting of exotic nectar-plants in gardens. However, this trend does not necessarily reflect their overall population stability, since breeding bird survey data for this region are lacking.

Inland West

Inland in the western U.S., Breeding Bird Survey data indicates Rufous Hummingbird populations are stable currently. But their relative rarity in this region during summer remains apparent. Conservation of fragile breeding habitats will be crucial for this species’ future.

Alaska and Canada

In Alaska and Canada, Rufous Hummingbirds occur in low densities and localized distributions, but survey data suggest stable or increasing numbers in most areas. These northern breeding strongholds will be important to monitor for effects of climate change in the coming decades.

Ensuring healthy Rufous Hummingbird populations into the future depends on mitigating habitat loss in their breeding range, providing adequate migratory stopover habitat, and minimizing climate change impacts across their range. Continued monitoring of populations and research into migration ecology will inform beneficial conservation strategies for this fascinating species.

Conclusion

In summary, Rufous Hummingbirds are considered uncommon to rare across substantial portions of their breeding range due to specific habitat requirements and extremely long migration distances. However, population trends appear to be stable currently in most regions. Maintaining their specialized breeding and migratory habitats will be key to ensuring their continued rarity rather than decline to endangered status. With thoughtful conservation measures, these tiny travelers will hopefully continue lighting up skies with their fiery plumes each summer.