Hummingbirds are some of the smallest and most fascinating birds. Their rapid wing beats, ability to hover and fly backwards, beautiful iridescent colors, and important role as pollinators capture people’s attention. An interesting aspect about hummingbirds is how quickly they grow and develop from tiny eggs to independent juveniles leaving the nest.
Newly hatched hummingbirds
Hummingbird eggs are very small, often not much larger than a jellybean. However, they contain everything needed for the embryo to develop into a hatchling. Incubation periods for hummingbird eggs range from 14-23 days depending on the species. When hummingbird chicks first hatch, they are tiny, naked, blind, and helpless. Their eyes are sealed shut, they have no feathers, and they are completely dependent on their parents for food, warmth, and protection.
Physical development in the first week
In their first week after hatching, hummingbird chicks develop very rapidly. Their eyes open within a few days, giving them their first glimpse of the world. A covering of soft downy feathers starts to grow in to help retain body heat. By age 5-7 days, hummingbird chicks already strongly resemble adult hummingbirds, just on a smaller scale. Their wings and tail feathers begin growing in at this point.
Growth of flight feathers
The next big step in a baby hummingbird’s development is the growth of their flight feathers on the wings and tail. These long, narrow feathers are critical for being able to fly. They start emerging when the birds are around 7-10 days old. The flight feathers continue growing and developing until the birds are ready to make their first flight at around 3 weeks of age.
Leaving the nest
Baby hummingbirds stay in the nest while they are still developing their flight feathers and building up their wing muscles. They are fed by their mothers the entire time. Then, at some point between 18-26 days after hatching, the young hummingbirds decide it’s time to leave the nest and fly off into the world.
The exact timing depends on the species. For example, here are estimated fledging ages for a few common North American hummingbirds:
| Species | Days to Fledging |
|---|---|
| Ruby-throated Hummingbird | 18-23 days |
| Rufous Hummingbird | 20-22 days |
| Allen’s Hummingbird | 22-26 days |
| Calliope Hummingbird | 18-23 days |
As you can see, most species fledge somewhere between 18-26 days after hatching. So, on average, baby hummingbirds leave the nest when they are about 3 weeks old.
The first flight
The first flight for a young hummingbird, known as its fledging flight, is a major and risky milestone. The hummingbird perches on the edge of its nest and uses its rapidly beating wings to lift off. Often the bird will hover and fly briefly back and forth to nearby perches and back to the nest. These early flights are shaky and lack finesse.
Sometimes the first flight is a direct path away from the nest as the young hummingbird heads off into the world for good. But even after fledging, the baby birds still have a lot to learn. Their flight skills, such as hovering, flying backwards, and maneuvering, need more practice. And they don’t yet have the feeding skills to obtain all the nectar and insects they need.
Care after leaving the nest
In the first days and weeks after fledging, young hummingbirds still rely heavily on their mothers for care and feeding. They beg and chase after her when they are hungry, relying on her to lead them to flower patches and other food sources. As they practice flying and foraging, their skills gradually improve.
This post-fledging period lasts anywhere from a few days in some species up to 3-4 weeks in Allen’s and Rufous hummingbirds. By aggressively chasing their young away from their territory, mother hummingbirds encourage the juveniles to become fully independent at the appropriate time.
Interestingly, some research indicates that occasional feedings by the mother may continue sporadically for a month or longer in some species, especially of the young hummingbird is struggling to feed itself or is still hanging around her territory.
Surviving to adulthood
The journey from a 2 gram hatchling to an independent juvenile is an extremely risky one for hummingbirds. Their tiny size, need for frequent feeding, vulnerability in the nest, and high metabolic needs mean mortality rates are high.
It’s estimated that between 70-80% of hummingbird nestlings and fledglings may die due to factors like starvation, weather, predators, and accidents. However, those that do successfully fledge from the nest and make it through the first few weeks and months have a high chance of surviving to adulthood.
By 1-2 months of age, most juvenile hummingbirds are competent at flying, feeding on their own, and avoiding predators. They are ready to migrate, if the species is migratory, and to survive on their own going into their first winter.
Variation between species
While the general time frame is the same, the exact age at which hummingbird fledglings leave the nest can vary by species due to differences in size, development rate, and behavior.
For example, Calliope hummingbirds are one of the smallest species, so they reach adult size and flight capability quickly, fledging at 18-23 days like their Ruby-throated cousins. Larger hummers, like Allen’s and Rufous, seem to need a few extra days.
Here are some more details on fledging ages that researchers have observed for particular kinds of hummingbirds:
Ruby-throated Hummingbird
– 18-23 days after hatching
– May flee nest if disturbed at 16 days
– Male and female fledge at same age
Black-chinned Hummingbird
– 18-22 days after hatching
– Male and female fledge at same age
Rufous Hummingbird
– 20-22 days after hatching
– Males may fledge 1-2 days earlier than females
Allen’s Hummingbird
– 22-26 days after hatching
– Males fledge at 22-24 days, females 24-26 days
Calliope Hummingbird
– 18-23 days after hatching
– Male and female fledge at same age
As you can see, even within a species there is a normal range of 16-26 days when fledging typically occurs. The largest sources of variation are likely the size of the hatchling, how quickly it grows and gains flight capability, and how much the mother continues to feed.
How can you tell if a hummingbird is ready to fledge?
If you are lucky enough to spot a hummingbird’s nest in your yard and observe it regularly, you may get to witness the exciting moment when the chicks fledge. How can you tell when the babies are getting ready to take their first flight? Here are some signs the young hummingbirds are nearly fledged:
- Rapid wing flapping and exercise of flight muscles while perched
- Wing and tail feathers are fully emerged and well-developed
- Moving around the nest frequently and perching on the rim
- Pausing nest activity and appearing alert when noises occur
- Preening and organizing feathers repeatedly
- Sleeping partly outside the nest
- Less begging of the mother for food
The presence of feather sheaths on the tips of the flight feathers can help estimate a hummingbird’s age and how far along they are in development. But even if you don’t know the exact age, these behaviors will let you know fledging is imminent! Once the hummingbird perches on the edge of the nest and starts fluttering those wings, get your camera ready.
Fledging weather and time of day
Hummingbird fledglings don’t get to choose the exact moment their first flight occurs, but certain weather conditions and times of day tend to be most favorable.
Mild weather with minimal wind and rain are important so the young birds aren’t blown around or chilled. Bright sunny mornings often provide good fledging conditions. The warmer air makes it easier for the hummingbirds to generate lift and fly.
Many hummingbirds fledge in the morning between 6-10 am. The already-warm temperatures help, and ample daylight remains for the critical first day of flying. However, some young hummingbirds become impatient and will fledge in the evening hours too.
Risks and dangers when fledging
That first fledging flight is fraught with dangers for a naive young hummingbird. Their flight skills are weak, and they are prone to accidents like colliding with trees and manmade objects. One study showed 23% of newly fledged hummingbird suffered an injury, often to the beak or wings.
Exhaustion is another risk if the young bird can’t find food sources fast enough to meet its high metabolism. And predators like birds of prey, snakes, and cats seize on the opportunity to snatch a clumsy fledgling.
Natural selection helps hummingbirds fledge at an optimal time when risks are balanced by the benefits of leaving the confines of the nest. But the process is still perilous for an animal that weighs less than a penny! Hundreds of thousands of baby hummingbirds don’t survive this vulnerable life stage each year in North America.
Conclusion
Baby hummingbirds grow amazingly fast, transitioning from tiny hatchlings to fledged juveniles in just 18-26 days. The actual timing of a hummingbird’s first flight depends on factors like size, development rate, species behaviors, and the mother’s willingness to continue nurturing.
While the general time frame is similar across most hummingbird species, there can be a few days of variation in the average. Providing adequate energy, avoiding hazards, and learning to feed are critical challenges for young hummingbirds after they fledge and start life on their own.
