Hummingbirds, with their iridescent plumage and aerial agility, are known for their rapid wingbeats and hovering flight. They play a unique role in ecosystems as pollinators. Their life cycle, particularly their reproductive behaviors, showcases adaptations and displays.
Understanding the Mating Season
Hummingbird mating season varies by species and geographical location. In warmer climates, some species like Anna’s Hummingbirds breed from November through June. For many North American hummingbirds, the breeding season starts in spring after returning from wintering grounds. Ruby-throated hummingbirds, for instance, see males arrive in mid-March, with females following two weeks later, and their breeding season can extend into July.
Environmental factors trigger mating season. Increased daylight hours signal spring, prompting migratory species to return to their breeding territories. Warmer temperatures also contribute, ensuring an abundant supply of food sources. Hummingbirds rely on nectar from flowering plants for energy and insects for protein, both of which become plentiful as the weather warms. The availability of these resources is important for the energy-intensive activities of courtship, nesting, and raising young.
Courtship Displays
During the mating season, male hummingbirds engage in courtship rituals to attract females. These displays involve aerial acrobatics and visual signals. Males often perform dive displays, ascending to heights, often up to 100 feet, before plummeting downward at high speeds. The Anna’s hummingbird, for example, can reach speeds of up to 60 miles per hour during these dives.
As the male pulls out of the dive, he may produce a chirping or buzzing sound. This sound is not vocal but is generated by the vibration of his tail feathers as air whips through them at high speed. Some species, like the Ruby-throated hummingbird, perform a wide U-shaped arc, with the male often retracing the path precisely. These performances, which can last about 12 seconds, demonstrate the male’s strength, agility, and fitness to potential mates.
Nesting and Rearing Young
After mating, the female hummingbird takes on the sole responsibility for nesting and rearing her young. Male hummingbirds do not participate in nest building, incubation, or feeding the chicks. The female constructs a tiny, cup-shaped nest, often no bigger than a quarter or walnut shell, typically 10 to 90 feet high in trees or shrubs. She weaves together plant fibers, moss, and leaves, using spider silk to bind the materials and anchor the nest. Spider silk’s elastic nature allows the nest to stretch as the nestlings grow.
The female lays two tiny, white eggs, usually one or two days apart. She begins incubation once both eggs are laid, lasting 14 to 21 days, varying by species and conditions. During incubation, the female sits on the eggs almost continuously, leaving briefly to feed, ensuring consistent temperature.
Hatchlings are altricial, meaning they are born blind, naked, and dependent on their mother for warmth and food. She feeds her chicks a high-protein diet of insects and nectar by regurgitation. Hummingbird chicks grow rapidly, fledging within 18 to 28 days of hatching. She continues to care for them for about a week after fledging, teaching them to forage independently.