Hummingbirds, with their iridescent feathers and rapid wingbeats, are a familiar sight in many gardens during warmer months. As temperatures drop and flowers fade, a common question arises: where do these tiny birds go? The answer for most North American species lies in remarkable annual journeys, driven by instinct and survival.
Migratory Patterns
Most North American hummingbird species travel south to warmer climates for winter, primarily Mexico or Central America, with some venturing as far south as Panama. These journeys can span hundreds or even thousands of miles. The Ruby-throated Hummingbird, a common species east of the Mississippi, often travels to southern Mexico and Central America, with some individuals remaining in the southern United States along the Atlantic and Gulf Coasts.
The Rufous Hummingbird undertakes one of the longest migrations for its size, covering nearly 4,000 miles from its northern breeding grounds in Alaska and Canada to wintering sites in Mexico. This species typically moves up the Pacific Coast in spring and returns through the Rocky Mountains in late summer and fall, forming a clockwise loop. Other western species like the Black-chinned and Broad-tailed hummingbirds also migrate to western Mexico or Central America. Most hummingbirds begin their southward journey in late summer or early fall, often spurred by decreasing daylight hours rather than immediate cold or hunger.
Reasons for Migration
The primary drivers for hummingbird migration are the availability of food and suitable temperatures. As cooler weather arrives in northern breeding grounds, nectar-producing flowers become scarce. Insects, which provide hummingbirds with essential protein, also become less abundant. Hummingbirds have an exceptionally high metabolic rate, requiring constant access to energy-rich nectar to sustain their hovering flight and fast-beating hearts.
Prolonged cold temperatures pose a significant threat to these small birds. Their high metabolism means they burn energy quickly to stay warm. Without sufficient food sources to fuel this demand, surviving cold northern winters would be impossible for most species. Migration allows them to access regions where flowers bloom year-round and insects remain plentiful, ensuring their survival until conditions improve in their breeding territories.
The Journey’s Demands
The migratory journey itself is an incredible feat of endurance. Before departing, hummingbirds enter a phase of intense feeding, known as hyperphagia, to build up substantial fat reserves. They can gain 25-40% of their body weight, with some even doubling it, to fuel their long flights. This stored fat provides more than twice the energy per gram compared to carbohydrates or protein and also produces water, helping to prevent dehydration during flight.
Hummingbirds fly alone, often following the same paths year after year, and typically fly low to the ground to spot food sources. To conserve energy during the journey and overnight, hummingbirds can enter a state of torpor, similar to a brief hibernation, where their metabolic rate and body temperature significantly decrease. This allows them to stretch their energy reserves, particularly when food is scarce or during cold nights.
Hummingbirds That Don’t Migrate
While most North American hummingbirds migrate, some species or populations remain in certain regions year-round. The Anna’s Hummingbird is a notable exception, residing throughout the year along the Pacific Coast, from northern Mexico into parts of southern Canada. Their ability to tolerate colder temperatures and adapt to new food sources, such as exotic flowering trees and human-provided feeders, has expanded their non-migratory range.
Other species, like some Allen’s Hummingbirds in southern California, and Buff-bellied Hummingbirds in South Texas, also maintain non-migratory populations. These resident hummingbirds survive winter by relying on consistent food sources, including native winter-blooming plants and backyard feeders. Even among migratory species, some individuals may occasionally overwinter in milder climates along the southern U.S. coasts, particularly if food is available.