Hummingbirds are the smallest birds in the world, known for their high metabolism and unique ability to hover and fly backward. Their reproductive habits are complex, requiring immense effort from the female, who manages the entire process alone. Understanding the incubation period is key to grasping the dedication required to raise a new generation.
The Specific Incubation Period
The incubation period typically ranges from 14 to 21 days, with 16 to 18 days being common for many North American species like the Ruby-throated Hummingbird. The female is the sole provider of warmth and protection, as the male plays no role in the nesting process.
The mother is dedicated, often sitting on the nest for 50 to 55 minutes out of every hour to maintain a constant temperature. She leaves only for very short foraging trips to refuel her body. Absences must be brief because the tiny, pea-sized eggs—the smallest of any bird—can cool rapidly.
The typical clutch consists of two small, white eggs, usually laid a couple of days apart. Incubation begins as soon as the first egg is laid, meaning the eggs may not hatch simultaneously. This difference creates a slight age gap between the two altricial chicks, who are born naked and helpless.
The Full Nesting Timeline
The mother’s commitment begins before incubation, starting with nest construction. The female spends about 5 to 10 days meticulously building a small, cup-shaped structure using soft plant down and spider silk. She often camouflages the exterior with pieces of lichen.
Once the nest is complete, she lays her two eggs over one to three days. After incubation, the intensive nestling phase begins. The young remain in the nest for an additional 18 to 25 days as they grow rapidly and develop feathers.
The mother constantly forages for tiny insects and nectar to feed her offspring through regurgitation. The total time from the first egg being laid until the young birds fledge, or leave the nest, is approximately five to six weeks. They may remain dependent on the mother for a few more days before achieving full independence.
Factors That Influence Incubation Length
The incubation period is a range influenced by several environmental and biological variables. Ambient temperature is a primary factor influencing the duration the mother sits on the eggs. In cooler weather, the female must spend more time on the nest to maintain warmth, which extends the incubation period.
Nests at higher altitudes or those experiencing a cold snap can push incubation toward the longer end of the range, potentially lasting up to 22 days. If the weather is consistently warm, heat transfer is more efficient, and eggs may hatch closer to the 14-day mark. Species variation also plays a role; for example, the Allen’s Hummingbird has an average incubation period of 17 to 22 days.
The mother’s physiology and foraging success also impact the timeline. She must leave the nest to feed herself, but her ability to quickly find sustenance allows her to return rapidly. This minimizes the time the eggs are exposed to cooling temperatures, as prolonged cooling slows the growth process.