The calliope hummingbird (Selasphorus calliope) is the smallest breeding bird in North America and one of the smallest hummingbirds in the world. These tiny birds weigh just 2-3 grams on average, about the same as a penny. Despite their diminutive size, calliope hummingbirds embark on an immense annual migration covering thousands of miles between their breeding grounds in the western United States and Canada to their wintering grounds in Mexico.
Breeding Range
During the spring and summer breeding season, calliope hummingbirds are found primarily in mountainous areas of the western United States including the Rocky Mountains, the Cascade Range, and the Sierra Nevada Mountains. Their breeding range extends from southern British Columbia in Canada south through Washington, Oregon, California, Nevada, Idaho, western Montana, Wyoming, Utah, Colorado, northern Arizona, and northwestern New Mexico.
Within their breeding range, calliope hummingbirds prefer high elevation meadows, mountain forests, and stream edges. Some key areas where these tiny hummingbirds nest include:
- The eastern slopes of the Cascade Mountains in Washington and Oregon
- The Sierra Nevada Mountains of California
- The Rocky Mountains from British Columbia to New Mexico
- Mountain ranges in Nevada, Idaho, and Utah
During the breeding season, female calliope hummingbirds build tiny, thimble-sized nests out of plant down, spider webs, and lichens. They lay 1-3 tiny white eggs and incubate them for 14-19 days. The chicks hatch and fledge in another 18-22 days.
Fall Migration
As summer comes to an end, calliope hummingbirds begin migrating south to their wintering grounds. Most leave the breeding grounds starting in late July, though some may linger into early September.
The southbound migration route passes through mountain ranges of the western United States, including:
- The Cascades and Sierra Nevada in Washington, Oregon, and California
- The Rocky Mountains in Idaho, Montana, Wyoming, Colorado, Utah, and New Mexico
- Mountain ranges in Nevada and Arizona
As they migrate, calliope hummingbirds stop to rest and refuel on nectar in mountain meadows, parks, and backyards where flowering plants provide food. Some key stopover sites include:
- Mount Rainier and Mount St. Helens in Washington
- Crater Lake National Park in Oregon
- Yosemite and Sequoia National Parks in California
- Grand Teton National Park in Wyoming
- Rocky Mountain National Park in Colorado
From there, most calliope hummingbirds cross the border into Mexico and continue their migration south through the Sierra Madre Occidental and Sierra Madre Oriental mountain ranges. Their wintering grounds are mainly located in southwestern Mexico in the states of Sinaloa, Jalisco, Michoacán, México, Puebla and Oaxaca.
Winter Range in Mexico
Calliope hummingbirds spend the winter in forested mountain areas of southwestern Mexico at elevations between 5,000-9,500 feet. This region has a subtropical highland climate providing the nectar-flowers and insect food these tiny birds rely on.
Some specific wintering sites include:
- Sierra de Manantlán Biosphere Reserve
- Chamela-Cuixmala Biosphere Reserve
- Cumbres de Monterrey National Park
- El Cimatario National Park
- La Malinche National Park
In their Mexican wintering range, calliope hummingbirds are found in pine-oak forests, cloud forests, tropical deciduous forests, and scrublands. They also forage in mountain meadows, backyard gardens, and along streams and canyon edges.
Key nectar-producing flowers calliopes feed on during winter include:
- Salvias
- Sages
- Fuchsias
- Columbines
- Lilies
- Coral honeysuckle
- Firecracker flowers
They also eat small spiders and insects to get protein. By eating every 10-15 minutes from dawn to dusk, these tiny hummingbirds are able to survive cold mountain winters.
Spring Migration
As winter ends, calliope hummingbirds begin migrating back north to their breeding grounds. They follow blooming plants and seasonal nectar sources along a route through inland mountain ranges.
Key stopover sites where the birds rest and refuel include:
- Chisos Mountains in Big Bend National Park, Texas
- Madrean Sky Islands in southeast Arizona
- White Mountains in east-central Arizona
- Southwest Colorado
- Wasatch Mountains in Utah
From there they disperse back to breeding sites throughout the western mountains. Males arrive first by early April to establish breeding territories. Females follow by late April to early May. Upon returning to their breeding grounds, the migratory cycle begins again.
Threats and Conservation
Once considered common summer residents throughout their breeding range, calliope hummingbird numbers have declined significantly in recent decades. Loss of habitat, climate change, and pesticide use are major threats. Calliopes are now listed as Near Threatened by the IUCN Red List.
Some conservation initiatives aiming to protect these tiny hummingbirds include:
- Habitat restoration projects providing nectar flowers along migration routes and on the wintering grounds
- Pesticide regulations restricting the use of harmful chemicals
- Citizen science monitoring programs tracking calliope populations and distributions
- Research on effects of climate change to guide mitigation strategies
- Captive breeding and release programs in some areas to boost numbers
Backyard birders can also help calliope hummingbirds by planting nectar sources, avoiding pesticides, installing feeders, and participating in citizen science surveys. With cooperative conservation efforts, these smallest of hummers can continue their incredible migratory journey for generations.
Key Facts
- Calliope hummingbirds are the smallest breeding bird in North America.
- They weigh just 2-3 grams on average.
- Breeding range extends through mountainous regions of the western U.S. and Canada.
- They migrate south in late summer/early fall through inland mountains to Mexico.
- Winter range is in pine-oak forests of southwestern Mexico.
- Migration route covers over 5,000 miles round trip each year.
- Population numbers have declined significantly in recent decades.
- Conservation efforts aim to provide habitat and reduce threats along their range.
Conclusion
The calliope hummingbird is a tiny bird that makes an incredible migratory journey each year. Breeding in mountainous areas of the western U.S. and Canada, they migrate south through inland mountain ranges in late summer and fall. Their winter range is located primarily in pine-oak forests of southwestern Mexico. The round trip migration covers over 5,000 miles annually for these diminutive hummers. Habitat loss and other threats have caused calliope hummingbird numbers to decline in recent decades. However, conservation initiatives focused on protecting habitat and reducing pesticide use can help safeguard the future of these smallest of North American breeding birds.