The calliope hummingbird (Selasphorus calliope) is the smallest breeding bird in North America and one of the smallest birds in the world, weighing just 2-3 grams on average. These tiny hummingbirds get their name from their distinct call that sounds like high-pitched peeping. Calliope hummingbirds have an extremely long migration route for their tiny size, traveling up to 5000 miles annually between their breeding grounds in the northwestern United States and Canada to their wintering grounds in Mexico. Understanding their migration patterns and the incredible distances they travel each year provides insight into the persistence and endurance of these smallest of birds.
Breeding Range and Nesting
Calliope hummingbirds breed in mountainous areas of the northwestern United States and Canada, primarily in California, Oregon, Washington, Idaho, Montana, Wyoming, and British Columbia. They prefer high elevation meadows, mountain forests, and stream edges that provide abundant nectar-bearing flowers. The breeding season lasts from May through August.
To attract females, male calliope hummingbirds perform elaborate courtship displays. They fly in repeated U-shaped patterns, reaching speeds of up to 60 body lengths per second while diving. These courtship displays demonstrate the male’s strength and agility.
Once females choose a mate, they build a tiny cup-shaped nest out of plant down, spider webs, and lichens on the upper branches of trees and shrubs. The female lays just two tiny white eggs and incubates them for 15-16 days. The chicks hatch and fledge in about 3 weeks, an incredibly short time considering their small size and the long migration ahead.
Fall Migration
In late summer and early fall, calliope hummingbirds begin their long southerly migration to their wintering grounds. The southward migration starts as early as late June and continues through August, with the bulk of the migration happening in August and September as food supplies dwindle and cold temperatures set in.
Calliope hummingbirds migrate relatively early compared to other North American hummingbirds for their size. Their small body size makes them vulnerable to cold temperatures and freezing nights, so migrating early to warmer southern climates improves their chances of survival. Their early migration also ensures they have enough time to reach their distant wintering grounds.
During migration, calliope hummingbirds fly during the day and rest at night. They stop periodically to rest and refuel, primarily on nectar from flowers and small insects like gnats, aphids, and spiders. Excellent hoverers, they are able to feed while hovering in front of flowers.
Calliope hummingbirds migrate over land, flying low through mountain passes and river valleys. They generally migrate along the Pacific Flyway route through California, Nevada, Arizona, and New Mexico to Mexico. Some populations migrate east of the Rocky Mountains as well. They fly at an average speed of 20-30 miles per hour but have been recorded flying up to 60 miles per hour during a dive!
Wintering Range in Mexico
Calliope hummingbirds spend the winter in central and western Mexico, primarily in the Mexican Highlands between elevations of 5000 to 8000 feet. Their winter range includes areas in the states of Sinaloa, Durango, Zacatecas, Jalisco, Michoacán, México, Puebla, Oaxaca, and Chiapas.
In their winter habitat, calliope hummingbirds prefer pine-oak forests, shade coffee plantations, and arid scrublands rich with flowering plants. Favorite nectar sources include agaves, ocotillo, and eucalyptus flowers. They continue to feed on small insects as well.
To conserve energy, calliope hummingbirds go into torpor on cold nights, lowering their body temperature and heart rate. They may also enter torpor on excessively hot days to avoid overheating.
Not much is known about whether individual calliope hummingbirds return to the same winter sites each year. Banding studies show they often return to the same breeding sites in spring, suggesting they may also be site faithful on their wintering grounds.
Spring Migration
As spring approaches, calliope hummingbirds begin the long journey back north to their breeding grounds. They depart their wintering grounds as early as late January but most leave Mexico in March and April. Their spring migration is slower than in fall, likely because there is less urgency and the birds make more frequent stops to feed.
Calliopes once again travel along the Pacific Flyway through the southwestern United States. The males tend to migrate earlier than the females and select the optimal breeding territories before the females arrive.
Upon arriving back on their breeding grounds in May and June, males perform their elaborate courtship dances to attract females. The cycle then begins again, with females building their tiny nests and raising new chicks to continue the calliope’s story of persistence.
Total Migration Distance
The total migration distance covered by calliope hummingbirds each year is astonishing for such tiny birds. They travel between breeding grounds as far north as Canada down to wintering grounds centered in Mexico. Though their migration routes can vary, the average total distance traveled each way is an estimated 2,500 – 5,000 miles!
Here are some examples of estimated total migration distances:
- Breeding in British Columbia to wintering in Mexico: 5,000 miles
- Breeding in Idaho to wintering in Mexico: 3,500 miles
- Breeding in California to wintering in Mexico: 2,500 miles
The longest documented calliope hummingbird migration recorded by banding was from breeding grounds in British Columbia to wintering grounds in Chiapas, Mexico – a whopping 5400 mile round trip journey!
This means tiny calliope hummingbirds may fly up to 5000 miles or more annually as part of their seasonal migration. It’s an incredible feat for a bird weighing less than a nickel!
How Do They Fly So Far?
Calliope hummingbirds have many physiological and behavioral adaptations that enable them to complete their epic migrations each year:
- High fat reserves – They build up fat reserves equal to about 25-30% of their body weight before migrating.
- Hover feeding – Their ability to hover and feed while in flight allows frequent refueling.
- Torpor – They use torpor on cold nights and excessively hot days to conserve energy.
- Optimal flight – Their high metabolism allows very efficient conversion of food to energy for flight.
- Short wings – Their short wings provide optimum lift and hover performance.
- Site fidelity – Returning to the same sites each year provides familiarity.
These adaptations allow calliope hummingbirds to sustain their epic migratory journeys year after year. Their incredible flying skills and endurance has ensured the survival of these smallest of birds despite the vast distances they cover.
Threats During Migration
The arduous migration undertaken by calliope hummingbirds makes them vulnerable to many threats along the way, including:
- Habitat loss – Deforestation and urbanization eliminates crucial rest stop habitat.
- Climate change – Drought and severe weather events disrupt flowering schedules and food availability.
- Window collisions – Migrating calliopes can collide with windows on buildings.
- Fatigue – Exhaustion making them prone to predation or starvation.
- Starvation – Lack of food at migratory stopover sites.
- Predators – Vulnerability to hawks, jays, and other predators, especially when exhausted.
Sufficient stopover habitat along their migration routes is critically important to allow calliope hummingbirds to rest and refuel. Providing flowering plants and artificial feeders in gardens and parks can support these migrants as they pass through. Reducing obstacles like windows through the use of deterrents can also reduce collision risks.
Importance of Migration
The incredible 5000 mile migratory journey made annually by tiny calliope hummingbirds between their northern breeding and southern wintering grounds is an amazing feat of endurance. This arduous migration is driven by their specialized adaptations and site fidelity that has ensured the survival of this delicate species.
Some key reasons why migration is so important for calliope hummingbirds include:
- Access to optimal breeding grounds with abundant food for rearing young.
- Escape harsh winters and freezing temperatures by moving south.
- Take advantage of seasonal peaks in food availability, flowers, and insects.
- Return to familiar and proven breeding and wintering sites each year.
- Complete their breeding cycle and perpetuate the species.
Calliope hummingbirds time their migration to make the most of widely separated northern feeding grounds and southern wintering habitats. Though migration is filled with hazards, these tiny trooper’s persistence pays off in allowing both survival and successful breeding.
Their long migrations may be arduous, but they demonstrate the incredible endurance of one of the world’s tiniest birds. Calliope hummingbirds continue to persist thanks to the providence of their 5000 mile migratory journeys between the northern latitudes and Mexico each year.
Conclusion
The calliope hummingbird lives up to its namesake as a hardy hero by undertaking an epic 5000 mile round trip migratory journey every year. These tiny birds breed in mountainous regions of northwestern North America as far north as Canada, then migrate long distances to winter in the highlands of Mexico. Though a hazardous endeavor for a bird weighing just grams, their specialized adaptations allow calliopes to complete the round trip migration with remarkable endurance and precision. Understanding the migration patterns of calliope hummingbirds provides insight into their persistence despite diminutive size, while also revealing their vulnerability and reliance on networks of stopover habitat along the way. The migratory nature of calliope hummingbirds drives the seasonal movements that are essential for accessing optimal breeding conditions in summer and escaping harsh winters. Despite the risks, these smallest of birds continue to survive and thrive thanks to the epic 5000 mile migratory feat they perform annually.