Is down the same thing as feathers?

No. Natal down consists of simple, soft filaments lacking the interlocking barb structure of true feathers, which provide the rigidity needed for flight and weatherproofing. Down alone provides insulation but no flight capability or full weather protection, which is why downy chicks of tree- and cavity-nesting species stay in the nest until true feathers grow in.

Why do downy ducklings look so different from downy songbird chicks?

The difference reflects precocial versus altricial development rather than down itself: a duckling hatches with a dense, even covering of down over its whole body and open eyes, ready to walk and swim immediately, while a nestling songbird hatches with only sparse tufts of down over bare, often pink or grey skin, eyes closed, entirely dependent on the nest and parental feeding.

Bird Atlas

Downy Chick

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A downy chick is a hatchling covered in soft, fluffy natal down rather than true feathers — its exact appearance and mobility depend on whether the species is precocial or altricial.

What down is

Down is the soft, fluffy first covering many bird chicks hatch with, made of simple filaments that lack the stiff central shaft and interlocking barbs of a true feather. This structure makes down excellent for trapping air and providing insulation but useless for flight or shedding rain the way true feathers do — a downy chick is warm but neither waterproof nor capable of flight, and stays either nest-bound or close to a parent until true feathers grow in during the following weeks.

How much down a chick has, and how it looks, depends heavily on whether the species is precocial or altricial. A greylag goose gosling hatches with a dense, even coat of down covering its entire body, eyes open, ready to leave the nest and follow its parents within hours. A nestling common starling, by contrast, hatches with only sparse tufts of down over mostly bare skin, eyes closed, and depends entirely on the nest's shelter and a parent's body heat for warmth in its first days.

From down to true feathers

As a chick grows, true feathers emerge from the same follicles that produced the natal down, typically pushing the down out to the tips of the new feathers before it is finally shed or worn away — this is why growing chicks of many species look temporarily scruffy, with tufts of old down still clinging to the ends of new, structured feathers. Once the first full set of true feathers (the juvenile plumage) is complete, the chick gains the ability to fly, thermoregulate more effectively, and — in precocial species already capable of movement — better weatherproofing against rain.

The speed of this transition varies enormously: fast-developing precocial species can reach flight capability within weeks, while some altricial species with long nestling periods take considerably longer to trade down for a complete, flight-ready set of feathers.