Songbirds and most seabirds
Songbirds and most seabirds have altricial young, meaning that the newly hatched birds are blind, featherless, and helpless. Immediately after hatching, altricial birds can do little more than open their mouths to beg for food. They remain in the nest where the parents can feed and protect them while they continue to develop. For the first week of life, most altricial birds cannot control their own body temperature and must be constantly brooded (kept warm) by their parents. By the end of the first week, their eyes are usually open and their feathers are beginning to emerge. During this period, nestlings can experience remarkable growth by doubling their body weight several times!
Precocial species, such as ducks and many shorebirds, are born fully feathered, mobile, and with eyes open. Incubation periods are longer for precocial birds than altricial birds, allowing for increased embryonic development in the egg, and therefore they have relatively advanced motor and sensory functions at hatching.
“Quack, quack! Yourself,” mimicked Harriett sardonically.