By Guest Contributor MELISSA BLOCK

Have you ever noticed that newly hatched birds all look different? For example, baby cardinals are born helpless, bald, eyes closed and heads bobbing. In contrast, Wood Duck babies—which look like miniature versions of their parents— jump from their nest box after just 24 hours.

Ornithologists classify birds as either altricial or precocial  to describe the degree of development in young birds at hatching. The classifications recognize that instead of a sharp dividing line between hatchlings that are precocial and those that are altricial, there is a range of precociality.

Altricial birds are born with their eyes closed, pretty much naked (some have little patches of down feathers), and act like bobble-heads, unable to hold their heads up and unable to maintain their body temperature. They are completely dependent on their parents for food, shelter, and warmth. Altricial birds must be fed and incubated by the parents. Altricial birds are usually incapable of moving around after hatching. Most songbirds, woodpeckers, and hummingbirds fall into this category.

Precocial birds are born with their eyes open, a dense and well-developed down cover, and leave the nest within a day or two of hatching. They can walk, run, swim, and find their food after a few hours of being hatched. Some precocial chicks can feed themselves very soon after hatching and can maintain their body temperatures. Although precocial birds are pretty much ready to go after leaving the nest, they will still be helped and protected by the parents.It is usually weeks until they can fly. Water birds, like ducks and geese, are usually precocial.

Some birds of prey and owls are an exception. While they are born with a well-developed coat of down, they are completely dependent on their parents for food and warmth. If you’ve ever seen any of the eagle cams, or owl cams, you can watch the newly hatched bobble-heads.