Hummingbirds are some of the smallest and most fascinating birds in the world. Their unique ability to hover mid-air thanks to rapidly flapping wings sets them apart from all other bird species. Hummingbirds exist only in the Americas, with over 300 different species calling North, South, and Central America home. While they may be small in stature, hummingbirds lead interesting lives. Their tiny size allows them to survive on nectar from flowers, a food source many larger birds can’t exploit. And they play a key role in plant pollination as they flit from bloom to bloom. Hummingbirds’ diminutive size also means their eggs and offspring are teeny-tiny. So just how small are hummingbird eggs? What does it take for them to successfully hatch? And how do the babies survive once they’ve entered the world? Let’s take a closer look at the incredible process of hummingbird eggs and hatchlings.
The Minute Size of Hummingbird Eggs
One of the most astounding facts about hummingbirds is the small size of their eggs. With birds, there is often a correlation between adult body size and egg size – after all, the egg must contain all the nutrients and energy for a chick to successfully hatch and survive. But hummingbirds lay the smallest eggs of all birds in relation to their body size. The eggs measure less than 1 cm long but must contain everything needed for the chick to develop, making them absolutely tiny.
To understand just how small hummingbird eggs are, let’s look at some measurements. The bee hummingbird is the smallest hummingbird species and the smallest bird in the world, with adults reaching lengths of just 2 inches and weighing 2 grams. They lay eggs that are about the size of a coffee bean – just 0.39 inches (10 mm) long and 0.25 inches (6.3 mm) wide. Eggs of larger hummingbird species may reach 0.5 inches (13 mm) long. But even the 0.5 inch egg is tiny when you consider the 4 inch size of an adult hummingbird’s body.
The tiny hummingbird egg must contain the entire embryo, yolk, and nutrients to sustain the growing chick. So the contents are very densely packed into a minute package! But the small size allows the female hummingbird to lay the perfect number of eggs to match the availability of food resources. The egg production matches the number of eggs the parents can successfully raise on the nectar and insect resources of their territory.
How the Hatching Process Works
The process of hummingbird eggs hatching takes roughly two to three weeks from the time the female lays the eggs until they hatch. Here are the steps in the hummingbird egg hatching process:
- The female hummingbird lays 1-3 tiny white eggs in a delicately woven nest about 3 cm across.
- She incubates the eggs for roughly 14-23 days. The body heat from the mother sitting on the nest keeps the eggs at the proper warm temperature for development.
- Inside the egg, the embryo develops air cells, blood vessels, and organs. Nutrients from the egg yolk sustain the growing chick.
- In the last days before hatching, the chick starts to pip – using an egg tooth to break a hole in the egg shell. This can take 12-24 hours of pecking before it creates a hole.
- Once the hole opens up, the chick keeps pecking to break the shell completely open and emerge from the egg.
- It takes energy and strength for the tiny chick to pip and hatch, so hatching can take a full day from initial pipping to fully exiting the egg.
Throughout the process, the egg must be kept at proper warmth and humidity levels for successful hatching. The female hummingbird’s constant incubating maintains ideal conditions. If she leaves the nest, hatching could be disrupted. So once she starts incubating, the mother is committed to sitting on the nest for long periods until hatching completes.
What Happens in the Egg During Incubation
When the female starts incubating, the hummingbird embryo inside the egg begins developing into a chick. Here’s an overview of what happens during incubation:
- Days 1-3: Fertilized cell starts dividing and elongating into a neural tube that will become the nervous system and backbone.
- Day 4: Heart begins beating; blood vessels and bones start forming.
- Days 5-8: Major organs like the eyes, lungs, and stomach develop.
- Days 9-14: Feathers begin growing; the beak becomes hardened; egg tooth develops for piping.
- Days 15-23: Yolk sac shrinks as nutrition is consumed; chick gets in position to pip egg.
The speed of development varies based on hummingbird species and temperature conditions. But in general, the tiny embryo transforms from a single cell into a fully formed chick ready to hatch in just two to three weeks!
Pipping and Hatching from the Egg
On day 14 to 23 of incubation, the fully developed chick starts the process of working its way out of the egg. This process is called pipping. The chick has developed a temporary egg tooth on the tip of its beak that allows it to peck a hole through the eggshell. It pecks a small hole then takes a 12 to 24 hour break before pecking more to crack the shell open.
Pipping and hatching take tremendous effort for the tiny hummingbird chick. Its egg tooth falls off shortly after hatching. Here are some key steps in the pipping and hatching process:
- The chick first pip a small hole in the eggshell, rotating within the egg to get properly positioned.
- After resting from creating the initial pip, the chick starts pecking off bits of shell to create a larger opening.
- It may take 12-24 hours from initial pip hole until the chick creates an opening large enough to emerge from.
- The chick has to contort its body to fully push out of the small hole, with its legs and wings folded in.
- Once free of the shell, it rests before unfolding to a normal bird position. This can take 4-6 hours.
- The mother may help remove fragments of attached shell and membrane from the wet chick.
This long intricate process shows just how challenging it is for the tiny hummingbird chick to escape its egg! But their determination results in a successful first entry into the outside world.
Hummingbird Chick Development After Hatching
Once the strenuous hatching process is complete, the hummingbird chick still has a long way to go in its development. Here’s a look at how hummingbird chicks grow and fledge after hatching:
Appearance After Hatching
A newborn hummingbird chick weighs only 0.6 to 1.5 grams – that’s less than the weight of a penny! Their bodies are almost featherless, covered in just a light gray down. Their eyes are sealed shut at hatching. They have a short non-functional beak and no tongue. It’s difficult for them to lift their heads or even control their neck muscles. These tiny helpless chicks are completely dependent on their parents for survival.
Early Care from Parents
For the first week, the mother hummingbird feeds the chicks by regurgitating nectar and insects into their mouths. She also broods them – sits on the nest to provide warmth. The father hummingbird may also bring food and assist with feeding. As they grow stronger, the chicks are able to lift their heads and move around in the nest.
Growing and Fledging
Within a week, hummingbird chicks open their eyes. Pinfeathers start growing in. Over the next couple weeks, they become covered in feathers until they reach adult plumage. The chicks grow very quickly – their weight can increase over ten times within the three week nestling period! By two weeks old, they develop enough neck strength to feed on their own by poking their beak into the parent’s mouth to get regurgitated food.
At three weeks old, the hummingbird chicks are ready to fledge and leave the nest. They will continue begging parents for food as they learn to fly and become adept at feeding on their own. The incredible growth from hatchling to fledgling is complete in just a few short weeks!
Conclusion
Hummingbird eggs and hatchlings are absolutely tiny, with egg size as small as 0.39 inches long. But the delicate eggs contain everything needed for the embryo to develop into a chick. Through a 14 to 23 day incubation period, the female hummingbird keeps the eggs at proper warmth for the chick to grow. The chick then spends hours pecking a hole through the egg tooth – an amazing feat for such a tiny creature. After hatching, the chick is still extremely small and undeveloped. With diligent care from its parents, the hummingbird rapidly grows and gains independence in just three weeks. The hummingbird’s early life – from egg to hatching to fledging – is a remarkable process considering its minute size. But evolution has equipped the hummingbird with everything it needs to succeed through each intricate stage of growth. The result is one of nature’s most spectacular and resilient birds that persists across the Americas, wowing us with its flying skills, colorful plumage, and key role in pollination.
