Altricial or Precocial Young Birds: Know the Differences

Altricial or Precocial Young Birds: Know the Differences

Whether you are a bird enthusiast or a casual observer, most of us have interacted with a baby bird or a young bird on the ground. Knowing a baby bird’s appearance and behavior can help you decide on the most appropriate action if you face the decision to intervene or leave the chick alone.

How is that?

Birds have two types of chicks: those that remain in the nest and depend entirely on their parents (altricial) or those that leave the nest within 1-2 days after hatching (precocial).

What is a precocial and an altricial chick?

All bird chicks are altricial or precocial or something in between.

• Altricial birds (also known as nidicolous birds) remain in the nest and depend on their parents for food, heat, and protection. Altricial chicks are born with closed eyes, naked, patches of down feathers, and unable to move away from the nest. Altricial birds include passerine birds, hummingbirds, swallows, woodpeckers, among others.
• Precocial birds (also known as nidifugous birds) are born with open eyes, a well-developed down cover, and leave the nest within a day or two after hatching. Precocial chicks can walk, run, and swim after a few hours of hatching. They can find their food, but they are usually helped and protected by their parents. Precocial birds include ducks, shorebirds, coots and allies, quails, and tinamous, among others.

Birds of prey, owls, and some seabirds are an exception; they are altricial but hatch with a well-developed down cover.

Altricial birds (left) remain in the nest and are largely naked at hatching. Precocial birds (right) leave the nest shortly after hatching and have a down cover at hatching.

Plumage in altricial and precocial birds

• Altricial birds are naked or with scarce patches of down after hatch. The down grows in specific areas of the body, often in the form of tufts on the shoulders, the top of the head, and the back’s center.
• Precocial birds have a dense, well-developed layer of down that covers the entire body. There are no naked areas in the body. In general, the down cover has color patterns that resemble the habitat coloring and patterns where the young birds will spend the first weeks of their life. The plumage patterns of young chicks help them to blend in with their habitats.

The Juvenile Plumage

The juvenile plumage replaces the down cover and constitutes a bird’s first true set of contour feathers.

• Juvenile plumage in altricial birds: the juvenile plumage begins to appear while the chicks are in the nest. The juvenile plumage begins with pin feathers on the wings followed by the rest of the body. The pin feathers grow and open up to form feathers that cover the body of the bird. The naked areas on the neck, belly, and face are the last to cover the juvenile plumage.
• Juvenile Plumage in precocial birds: the juvenile plumage begins to grow while chicks follow the parents during the first few weeks of life. Pin feathers are generally not visible and grow under the down cover. The juvenile plumage reveals itself as the down cover begins to fall off.

Altricial chicks (left) showing pin feathers. Precocial chick with pin feathers growing under the down. The juvenile plumage appears when the down begins to fall off.

In general, the first set of contour feathers in young birds is not as stiff and cohesive as in adult birds. The juvenile plumage also differs in color and pattern from those of adult birds. Juvenile plumages often have spots in dots’ shape on light-colored birds to help camouflage the chick from predators.

Altricial chick in juvenile plumage. Note the very short tail, the bare areas on the face, and the beak’s yellow base.

What happens after the chicks acquire the juvenile plumage?

Passerine birds: In most species, the juvenile birds separate from their parents when they become nutritionally independent. In some species, juvenile birds stay with their parents until the next breeding season. In others, chicks remain as family groups where young people help their parents raise next year’s chicks (their siblings).

Ducks: young ducks separate from their parents after they can fly. In some species, they separate even before they can fly.

Shorebirds: In highly migratory species, chicks are abandoned by their parents as soon as they become nutritionally independent. The parents begin their migration journey before the chicks can fly. The chicks follow the parents to the wintering grounds a few weeks later.

Hawks and owls: Generally, juvenile raptors and owls stay with their parents until they become nutritionally independent. This separation may take a few months or over a year.

Main differences between altricial and precocial birds

	Altricial	Precocial
Behavior:	Stay in the nest Unable to move They depend entirely on their parents. The majority is capable of perching on branches.	They leave the nest after 1-2 days. Able to walk and swim They can find their food, but their parents accompany them. They are mostly restricted to the ground.
Eyes at hatching:	Closed eyes. They start to open them after a few days.	Open eyes. Able to walk through obstacles and find food
Plumage at hatching:	Naked or only patches of down on the body Some altricial chicks such as raptors, owls, and seabirds have well-developed down after hatch.	No naked areas of the body at hatching but a well-developed down cover

Closing Remarks:

Understanding young birds’ behavior and appearance will help you decide if the chick you see on the ground is either an altricial or precocial bird. Knowing the differences will also help you decide whether to intervene or leave the chick under the care of its parents.
In general, it is not a good idea to pick up and try to help a baby bird. Typically a chick on the ground, whether altricial or precocial, is under its parents’ care.

If the chick still shows pin feathers, a short tail, and bare areas on the back, neck, and face, it is more likely to be an altricial bird that recently left the nest. These features suggest that the young bird is still unable to fly. The nest from which it came from and the parents are likely to be in the vicinity. If the parents are not around, they may be caring for the other siblings.

If the young bird has a well-developed cover of down and walks and swims well, it is most likely that it is a precocial bird and needs to be left alone.

Whether on the ground or in branches, altricial and precocial birds make persistent calls to alert their parents about their location. Their parents will quickly pinpoint their chicks’ location.

It is recommended to transfer it to an expert’s care only if the young bird is injured, is almost naked (fell prematurely from the nest), or runs the risk of being attacked by cats or dogs.

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References:

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• Gill, B. Frank (2003). Ornithology (Second Edition). W. H. Freeman and Company.
• Starck, J.M .; Ricklefs, R.E. (1998). Avian Growth and Development. Evolution within the altricial-precocial spectrum. New York: Oxford University Press.

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