Hummingbirds, with their iridescent plumage and astonishing aerial acrobatics, often inspire wonder about their lives, including their social behaviors.
The Truth About Hummingbird Mating
Hummingbirds do not form monogamous pairs. Instead, they exhibit a polygynous mating system, where one male may mate with multiple females during a single breeding season. Females typically also mate with multiple males, a behavior known as promiscuity. There is no pair bond between male and female hummingbirds; their interaction is brief, lasting only long enough for mating to occur. The male departs after mating, leaving the female to manage all subsequent parental duties.
Reasons for Non-Monogamous Behavior
Several ecological and evolutionary factors contribute to the non-monogamous lifestyle of hummingbirds. Nectar, their primary food source, is widely available and often cannot be easily defended as a single, concentrated resource. This means males do not need to provide food for females or offspring, reducing the incentive for pair bonding. Males have extremely high energetic demands, particularly during the breeding season, which drives them to maximize mating opportunities with as many females as possible to pass on their genes. Male hummingbirds are also highly territorial, but this aggression is primarily directed at defending rich feeding areas from other males, not at establishing a territory for a mate or family.
Courtship Displays and Nest Building
Male hummingbirds engage in elaborate courtship displays to attract females. These displays often involve aerial maneuvers, such as high-speed dive displays where the male ascends up to 100 feet (30 meters) and then plummets past the female, sometimes reaching speeds of 50 to 60 miles per hour. During these dives, some species create distinct sounds with their wings or tail feathers. Males also flash their iridescent throat feathers, or gorgets, to display their vibrant colors. A receptive female may signal her willingness to mate.
Following mating, the female takes on the sole responsibility of nest building. She constructs a tiny, cup-shaped nest, often in a tree or shrub, that is well camouflaged with materials like moss and lichen. The nest is intricately woven using soft plant down, leaf hairs, and spider silk. This spider silk allows the nest to stretch as the young grow. The construction process can take up to seven days.
Parental Care
Male hummingbirds have no involvement in raising the young. The female alone incubates the typically two pea-sized eggs, which hatch after about 12 to 15 days. Once the chicks emerge, blind and featherless, the mother tirelessly feeds them a diet of regurgitated insects and nectar. She also defends the nest from potential threats. This solo parenting requires the female to constantly forage for food to sustain herself and her rapidly growing brood.