Hummingbirds have a fascinating breeding and nesting behavior. The tiny birds build intricate nests and display complex parental care behaviors. One interesting aspect of hummingbird reproduction is the incubation period – how long the parents sit on the eggs before they hatch.
Incubation Period Overview
The incubation period is the amount of time between when a hummingbird lays eggs and when those eggs hatch. For most hummingbird species, this ranges from 14 to 23 days. However, the exact length depends on several factors:
- Species – Different hummingbird species have slightly different incubation periods.
- Geography – Hummingbirds in colder climates may have longer incubation.
- Time of Year – Eggs laid later in summer may hatch faster.
- Clutch Size – Larger clutches take longer to incubate.
During incubation, one or both parent hummingbirds will take turns sitting on the eggs to provide warmth. The parent will sit tightly on the nest, often not leaving for hours or days at a time. Proper incubation is essential for normal embryonic development and hatching.
Incubation Period by Species
Here is a breakdown of the typical incubation period for some common North American hummingbird species:
| Species | Incubation Period |
|---|---|
| Ruby-throated Hummingbird | 13-14 days |
| Rufous Hummingbird | 16-17 days |
| Allen’s Hummingbird | 16 days |
| Calliope Hummingbird | 15-18 days |
| Broad-tailed Hummingbird | 16-17 days |
| Black-chinned Hummingbird | 15-18 days |
As you can see, the incubation period tends to range from about two to three weeks for most common North American species. However, even within the same species, the exact incubation time can vary by a few days depending on factors like geography and weather.
Role of the Male and Female Parents
In hummingbirds, the female is solely responsible for building the nest, incubating the eggs, and brooding the hatchlings after they emerge. However, the male plays an important role as well.
Here are the general parental duties during hummingbird incubation:
- Female: Builds nest, lays eggs, incubates eggs, broods newly hatched chicks
- Male: Stands guard near nest, chases away intruders, feeds female while she incubates
The female hummingbird will spend the majority of the incubation period sitting tightly on the nest, leaving only briefly to preen and feed. Males defend the territory and may call to attract passing females. They also forage for food such as nectar and insects to bring back to feed the incubating female.
What Happens in the Nest
Hummingbird nests are incredible structures, often built on twigs or branches using soft plant down and spider silk. The female intricately weaves the nest materials into a small, expandable cup shape.
Once the outer shell is complete, the female lines the interior with down feathers. This creates a soft, insulated layer to help retain heat and moisture during incubation. Female hummingbirds have bare spots on their bellies just for directly contacting the eggs while incubating.
Incubation Process
When sitting on the nest, the female hummingbird settles her body down into the feathers so the eggs make direct contact with her bare belly. She may slowly rotate or shuffle the eggs periodically using her bill.
The parent’s body heat is transferred to the eggs, stimulating embryo development. The female must maintain the eggs at a proper temperature between 96-104°F and ensure adequate moisture levels.
To do this, the female frequently leaves the nest for just 5-10 minutes to drink, bathe, preen, or forage. During these recess periods, eggs are left uncovered to cool slightly. The parent returns quickly though to restore optimal egg temperature.
Hatching
Towards the end of incubation, the female spends more time on the nest, only leaving 1-2 times per day. She may even sleep on the nest at night. Just prior to hatching, the chick embryo starts “pipping” – using its egg tooth to break through the shell from inside.
It takes 12-48 hours between the start of pipping and the chick fully emerging. Once hatched, the altricial baby hummingbird is nearly featherless. The female continues brooding the chick in the nest, providing warmth and protection.
The chick grows quickly, developing feathers in around 2-3 weeks. At this fledgling stage, the young hummingbird will leave the nest and start learning to fly and feed itself.
Why the Incubation Period Matters
The incubation period is an extremely vulnerable time for hummingbird eggs. Without constant parental care, the eggs may fail to develop, overheat, get chilled, or be predated by animals. Even a short disruption in sitting could be detrimental.
That’s why hummingbird eggs typically hatch in about 2-3 weeks. This relatively short period allows the embryos to fully develop while minimizing risks.
A longer incubation time would increase opportunities for failure. For example, the parent may need to leave the nest more frequently to feed itself, exposing the eggs. Conversely, a shorter incubation period wouldn’t provide enough time for proper growth.
Through evolution, different hummingbird species have adapted incubation durations that maximize hatching success given their particular environments and reproductive strategies.
Interesting Facts About Hummingbird Incubation
Here are some fascinating tidbits about the hummingbird incubation process and nesting behaviors:
- Hummingbird eggs are only about the size of a coffee bean – the smallest of all birds.
- Nests may be reused for multiple broods in one season.
- Some tropical hummingbirds can lay eggs year-round with multiple clutches.
- High altitude species have longer incubation periods.
- The developing chicks chirp inside the shell near hatching.
- Females may add new nest materials during incubation.
- Parents are very defensive of the nest, attacking intruders.
Conclusion
Incubation is a critical part of the reproductive cycle for hummingbirds. The female dutifully sits for up to 23 days without leaving the nest for long. Her constant heat and moisture allows the tiny embryos to fully develop and hatch.
This intensive parental care early on ensures the best chances of survival for the next generation of these amazing pollinators. Understanding hummingbird incubation periods also provides insight into their evolutionary ecology and advanced nesting behaviors.
