The Bee Hummingbird (Mellisuga helenae) is the smallest bird in the world, measuring just 5-6 cm long and weighing 1.6-2 grams. This tiny bird is endemic to the island of Cuba and is best known for its rapid wing beats and ability to hover in place while feeding on nectar from flowers. Despite its diminutive size, the Bee Hummingbird exhibits complex reproductive behaviors common to many larger bird species. Read on to learn more about how these tiny birds find mates, build nests, lay eggs, and raise chicks.
Courtship and Mating
The breeding season for Bee Hummingbirds takes place between March and June each year. As this time approaches, male hummingbirds establish feeding territories with plenty of flowers rich in nectar. They use these territories to attract potential mates by performing elaborate courtship displays. A male Bee Hummingbird will fly back and forth in a U-shaped pattern in front of a perched female, rapidly beating his wings to produce a loud buzzing or “whirring” sound with his tail feathers. The male may also vocalize with chirps and whistles to get the female’s attention. If interested, the female will respond with similar vocalizations and allow the male to approach.
Courtship feeding often occurs next, where the male will collect nectar from his territory and present it to the female. This offering of nectar shows the female that the male has access to sufficient food resources to raise a family. If receptive, the female will allow the male to mount her and mate. The actual act of copulation is very brief, lasting just a few seconds. Once mated, the male and female go their separate ways and the male has no further involvement in nesting or raising the chicks. The female must carry out the rest of the reproductive process on her own.
Nest Building
About a week after mating, the pregnant female Bee Hummingbird will begin constructing a nest in which to lay and incubate her eggs. She selects a low hanging horizontal branch or twig, usually 3-6 feet above ground in the tip of a small tree or shrub. Using soft plant down collected from vegetation and spider silk gathered from spider webs, she carefully builds a tiny cup-shaped nest about the size of half a walnut. The outside of the nest is camouflaged with lichen and moss to help it blend in.
Inside, the nest is lined with soft plant fibers which the female shapes into a cup using her body. As she rotates within the cup, the movements of her feet work the fibers into the cup walls. The end result is an elastic, resilient nest just big enough to cradle two tiny eggs. Building the entire nest takes 6-9 days and represents a huge effort from such a small bird. But a secure, well-built nest helps ensure eggs and chicks will be protected.
Egg Laying and Incubation
Once nest construction is complete, the female Bee Hummingbird lays a clutch of just two pea-sized eggs. The eggs are creamy white with very little markings. She lays one egg per day, early in the morning.
Incubation begins as soon as the second egg is laid. The female takes sole responsibility for incubating the eggs, sitting on them for periods of 40-60 minutes followed by brief 5-10 minute breaks to feed. To incubate the eggs, she settles her body onto the nest with her feet drawn up into the feathers of her belly. This provides direct body heat transfer to the eggs beneath her.
The high metabolism of hummingbirds requires them to feed frequently, so incubation sessions are short but frequent, totaling about 60% of daylight hours. This attentive incubation ensures proper development of the growing embryos inside the eggs. After a period of 14-23 days, the eggs hatch in quick succession. The chicks are altricial, meaning they hatch naked, blind, and completely helpless – totally dependent on their mother for survival.
Raising Chicks
From the moment they hatch, Bee Hummingbird chicks are voracious eaters. They obtain all their early nutrition from their mother in the form of sugary nectar. The female spends most of her time flying from flower to flower collecting nectar which she carries back to the nest in her crop, a throat pouch where nectar is stored before being delivered to the chicks. She regurgitates this high energy nectar directly into the mouths of the chicks, feeding each one up to 1,300 times per day!
Incredibly, the chicks grow rapidly on this diet, nearly doubling in size within 24 hours of hatching. Their eyes open at around 3 days old and feathers begin growing visibly at 5 days old. By 12-18 days, the juvenile hummingbirds are fully feathered and ready to leave the nest. The female helps encourage them to fledge by stopping feedings, forcing the chicks to use their wings and venture out in search of food. They often return to the nest to roost for a few days after fledging.
From start to finish, the female Bee Hummingbird raises her chicks completely solo. Their tiny size belies the incredible amount of energy and dedication required for these diminutive birds to successfully reproduce and raise the next generation.
Key Facts
Courtship and Mating
- Breeding season lasts from March to June
- Males perform courtship displays like aerial dances and loud buzzing sounds
- Courtship feeding of nectar helps convince the female to mate
- Mating lasts just seconds with no further male involvement
Nest Building
- Female builds tiny cup-shaped nest in 7-9 days
- Nest is camouflaged with moss and lichens
- Plant down and spider silk form soft, resilient cup
- Nest is only big enough for two eggs
Egg Laying and Incubation
- Female lays two eggs, one per day
- Incubation lasts 14-23 days
- Female incubates eggs for 60% of daylight hours
- Frequent feeding is required during incubation
Raising Chicks
- Chicks hatch naked, blind, and helpless
- Female provides sugary nectar via regurgitation
- Up to 1,300 feedings per chick daily
- Chicks fledge in 12-18 days
Conclusion
Despite weighing less than a penny, the Bee Hummingbird successfully breeds each spring and summer through evolutionarily adapted behaviors. Intricate courtship displays by males help them find mates. Females build ingenious tiny nests to cradle eggs and chicks. Their high-energy nectar diet sustains nearly nonstop incubation and feeding of chicks. These diminutive birds perfectly exemplify avian reproductive success through specialized adaptations allowing them to thrive and continue their unique species. The Bee Hummingbird’s persistence in the face of its tiny stature is a marvel of nature.