This is one of a series presented by the National Aviary, America’s bird zoo. The National Aviary works to inspire a respect for nature through an appreciation of birds.
What hatches out of a bird’s egg can be homely and helpless or capable and cute, depending on what kind of bird it is. Hatchlings of altricial species start out life as small, oddly proportioned pink blobs, unable to see or stand up or feed themselves, and unable to keep warm without a parent to brood them. For many days they are little more than a big mouth and an over-sized digestive tract, kind of like the avian equivalent of a caterpillar. Depending on the species, altricial chicks must remain in the nest for 10 days to two or more weeks, until they develop their forelimbs (wings), hind limbs (legs), and enough feathers to give them the mobility they will need in order to survive outside of the nest.
Precocial young, on the other hand, are up on their well-developed legs and feet and raring to go within hours of hatching, needing only for their thick coat of downy feathers to dry off first. They will rely on their parents for protection but not for food — they feed themselves from the start. As they grow, they develop their flight feathers and eventually can fly, but this process takes many weeks longer than for altricial species, which can fly (more or less) as soon as they leave the nest.
All of the world’s songbird species — robins, sparrows, jays and the like — fall in the altricial category. Because their young require parental care for an extended period of time, most altricial species build a substantial nest capable of remaining intact for several weeks or more. Precocial birds include all wild and domestic fowl (chickens, turkeys, grouse and the like), shorebirds (sandpipers and plovers) and waterfowl (ducks, geese, and swans). The nests of these species are often little more than a scrape on the ground. That is because precocial young can leave the nest within hours after hatching. Although the parent birds do protect them from predators, precocial chicks feed themselves from day one.
At this time of year young birds of many kinds are newly on the wing. Some of these may look like they are alone, hopping awkwardly across your lawn, calling continually or maybe just sitting there looking a little bewildered and lost. Rest assured, though, that parent birds are pros at keeping tabs on their young, so it is a good idea to resist the temptation to “save” baby birds that you think have been orphaned.
The National Aviary abounds with baby birds at this time of year, too. Two fairy bluebird hatchlings are being hand-reared right now in our Avian Care Window, there is downy brood of ringed teal in the Wetlands, and many other species are incubating their clutches of eggs, all of which means it’s a good time to get cracking and come see what’s hatching.
— By Robert Mulvihill, National Aviary ornithologist