Before a bird is ready to find a mate and fly off into the sunset, it needs time to build confidence, come out of its shell (pun intended!), and allow its body to develop the necessary muscles and features that will help it survive life outside of the nest. From egg to air, the different stages of development are critical for a baby bird to become successful in adulthood.
Take a look at the different stages of baby bird development.
Blue Jay Eggs
In the Egg
Before even hatching, a baby birds undergoes a total transformation, developing from a mere embryo into a chick who’s ready to break through the confines of the eggshell. Depending on the species, it may be the only egg in the nest (as is the case with condors), or one of a whole fleet of offspring (up to 17 eggs for grey partridges) who will soon have to learn how to share with their siblings. Once ready, the baby bird uses a hardened bump on the tip of its beak – commonly called an egg tooth – to crack through the shell and make its grand entrance into the world. This may take a couple hours or a couple days. Talk about getting straight to work!
Hatchling Purple House Finch
The work doesn’t end there. Though strong enough to survive outside of the eggshell, the baby bird – now called a hatchling – still has a lot of development to get to. Most hatchlings haven’t yet opened their eyes, and they usually have very little downy fluff on their naked skin. Plus, they typically don’t have the muscle strength needed to move around much. As a hatchling, the baby bird is still incredibly vulnerable and has to rely on its parents for survival as it continues to develop its physique. A baby bird is considered a hatchling for about three days.
See also: What Do You Feed a Baby Bird?
A baby bird is considered a nestling anywhere from three to 14 days old – but the characteristics are more important than the actual age for determining the baby bird’s stage of development. A nestling has opened its eyes, and its bare skin is becoming covered with thicker downy fluff and thin, stringy tubes which will soon transform into the baby bird’s wing feathers. Though exciting things are happening, a nestling is still bound to life in the nest, relying on its parents for food and warmth.
Fully feathered and ready to make moves, a fledgling has developed enough muscle tone to start hopping, fluttering, and walking about. Flying is still a bit shaky, but the baby bird is definitely starting to figure out how those wings work. The parents still play an active role during this stage, and though the fledgling has ventured out of the nest, the parents are usually close by.
This is the stage of baby bird development that often excites and causes alarm for backyard birders. It’s not uncommon to come across a little fledgling in the yard and think that it’s injured. Fledglings are still learning how to use their body, so those jerky movements and failed take-offs can ultimately ring alarm bells for concerned birders. Though it may seem like fledglings need help, it’s best to leave them alone when they’re in this stage of development, as these failed attempts at flying are actually a valuable part of the baby bird’s learning process. Don’t worry – fledglings will figure it out just fine!
Juvenile Blue Jay
Some bird species then enter a stage of life where they’re not quite considered a baby, but not quite an adult either – hey, most of us can relate! A juvenile bird has mastered all the skills necessary for surviving on its own, like flying and finding food. However, a juvenile bird isn’t quite considered an adult yet, and there’s usually a distinguishing feature that can give birders a clue. For example, the juvenile’s proportions might be off by just a little as it continues to grow, or its markings haven’t reached full maturity. Bald eagles are a great example, as they’re actually born with a brown head and are still considered immature until those crown feathers turn white, which can take a couple of years.
Adulthood at Last!
Finally, a bird is considered an adult when it is sexually mature, meaning it’s able to reproduce, and it expresses the complete markings of adults for its given species.
It’s important to remember that every species is slightly different when it comes to development. Some birds skip certain stages while others take a bit longer to reach adulthood. Owls and ducks, for example, break out of their shells ready to go, skipping through the hatchling and nestling stages quickly to go straight for the fun stuff, like leaving the nest and finding their own food. Regardless of how fast a baby bird matures, every stage of development offers unique challenges that allow the bird to learn the skills needed to thrive as an adult.