The calliope hummingbird (Selasphorus calliope) is the smallest bird species in North America and one of the smallest in the world, weighing only 2-3 grams on average. These tiny birds breed primarily in the mountainous regions of western North America, including the Rocky Mountains, the Cascade Range, the Sierra Nevada, and the Coast Ranges. Their breeding habitat ranges from southern British Columbia down to northern Baja California.
The calliope hummingbird gets its name from its distinct vocalizations that resemble musical notes from a calliope or steam organ. The male’s song is a high-pitched squeaky chipping. This species is known for its vibrant plumage, with iridescent throats that range from bright red to purple depending on the angle of light. The female is primarily green with white tips on the tail feathers.
Breeding Range
The calliope hummingbird generally breeds between elevations of 1500-3000 meters in mountainous pine and fir forests, meadow edges, and stream sides. Its breeding range extends through the following states and provinces:
- British Columbia
- Alberta
- Washington
- Oregon
- California
- Nevada
- Idaho
- Montana
- Wyoming
- Utah
- Colorado
- Arizona
- New Mexico
- Baja California
Within this broad range, there are several specific breeding locations that are important strongholds for calliope hummingbird populations:
Key Breeding Locations
- Southern Rocky Mountains (Colorado, Wyoming, Utah)
- Sierra Nevada Mountains (California)
- Cascade Mountains (Washington, Oregon)
- Northern Coast Ranges (British Columbia)
- Transverse Ranges (California)
- Warner Mountains (California)
- Klamath-Siskiyou Region (Oregon/California border)
Some of the most dense breeding populations are found in subalpine meadows with abundant wildflowers in these mountain ranges. The availability of nectar-producing flowers is a key factor determining calliope hummingbird breeding habitat suitability.
Nesting and Reproduction
Calliope hummingbirds build very small, compact nests in order to breed. The female does most of the construction work, gathering plant down, spider webs, lichens, and buds to fabricate a delicate cup-shaped nest. Favorite nesting sites include pine branches, the undersides of logs, rock ledges, and low shrubs.
Nest Features
- Diameter: about 2.5 inches across
- Depth: 1-1.5 inches
- Exterior decorated with lichens and moss as camouflage
- Spider silk woven throughout for stability
- Lined with soft plant down
The female lays just 2 tiny white eggs, about the size of a jellybean. She incubates the eggs for 15-16 days before they hatch. The chicks remain in the nest for another 3 weeks, relying completely on the female for care as they grow their flight feathers.
Breeding Season Timeline
- April to May: Females arrive at breeding sites first and establish territories
- May: Nest building and egg laying
- May to June: Incubation and chick rearing
- June to July: Fledging of young
- August: southward migration for wintering grounds
The males depart the breeding territories earlier than the females. The winter range extends into Mexico and Central America. Remarkably, these tiny birds are capable of migrating thousands of kilometers between their summer and winter homes.
Habitat Requirements
Several key habitat features are required to support breeding calliope hummingbirds:
Mountain Meadows
Subalpine mountain meadows with abundant wildflowers provide critical feeding habitat. The birds have high metabolisms and require frequent energy intake from nectar. Some favorite flower species include:
- Indian paintbrush
- Columbine
- Larkspur
- Lupine
- Fireweed
- Penstemon
Water Sources
A clean, reliable source of water is vital for drinking and bathing. Small creeks, seeps, waterfalls, and rain pools in the mountains provide water. The birds sometimes drink droplets on vegetation if surface water is scarce.
Nesting Sites
The abundance of suitable nesting sites helps determine habitat quality and breeding population capacities. The birds need trees, shrubs, rock ledges, or logs sturdy enough to support a 2 gram nest. Pine and fir trees are frequently used.
Insect Prey
While nectar is the primary food source, the birds also eat small insects to obtain proteins and minerals. Larvae, beetles, flies, grasshoppers, and spiders are common prey. Breeding sites need adequate insect populations.
Threats and Conservation
The calliope hummingbird’s small population size and highly specific breeding habitat make it vulnerable to environmental threats:
Habitat Loss
Logging, urban development, meadow irrigation, and grazing pressures can degrade and reduce available breeding habitat in the mountains. Protecting subalpine ecosystems is crucial.
Climate Change
Flower blooming schedules may shift and mismatch with migration patterns. Drier summers could shrink water availability. Overall warming could enable other hummingbirds to encroach on calliope breeding grounds.
Wildfires
Severe wildfires can scorch meadows and burn up nesting sites. A warming climate may increase fire activity in western North America.
Threat | Impact on Breeding |
---|---|
Habitat Loss | Destruction of meadow feeding areas and nest sites |
Climate Change | Altered migration timing, competition from other species |
Wildfires | Incineration of nesting habitat |
To protect calliope hummingbird populations, conservation measures should focus on preserving subalpine breeding habitat, maintaining natural wildflower phenology, and reducing anthropogenic climate change. Expanded monitoring programs are needed to fill knowledge gaps about these smallest of mountain birds. With proactive habitat management, the calliopes’ high-pitched chipping song will hopefully continue resonating through western mountain ranges for generations to come.
Conclusion
The calliope hummingbird is a diminutive but mighty bird that breeds primarily in the mountains of western North America. This species depends on subalpine meadows rich in nectar-producing flowers and nesting sites in conifers and shrubs. Breeding occurs between April and July, with females incubating just two tiny eggs. Conserving high quality breeding habitat will be key for ensuring the future survival of calliope hummingbird populations in a changing climate. Through focused research and habitat protections, these tiny hummingbirds can continue gracing the alpine landscapes of the west with their vibrant plume and melodic song.