Molting takes a lot of energy, and losing a lot of feathers at once can make it hard for a bird to keep itself warm. Precocial species, on the other hand, are born with feathers and are fairly self-sufficient.Īll baby birds go through successive molts- periods when they lose the feathers they have and grow in a new set of feathers, before eventually reaching their adult plumage.

Altricial birds hatch naked and helpless their lack of feathers means that their parents can more efficiently transmit body heat directly to the babies' skin. Today, baby birds are on a spectrum in terms of how developed they are when they're born and how much help they need from their parents.

Illustration of what a newly hatched Enantiornithine bird may have looked like. 'We want to know, how did this process evolve? How did it differ across groups of birds? And how has that shaped bird evolution, shaped the survivability of all these different clades?' Two of O'Connor's recent papers examine the molting process in prehistoric birds.Ī paper in the journal Cretaceous Research detailed the discovery of a cluster of feathers preserved in amber from a baby bird that lived 99 million years ago. 'Molt is something that I don't think a lot of people think about, but it is fundamentally such an important process to birds, because feathers are involved in so many different functions,' says Jingmai O'Connor, associate curator of fossil reptiles at Chicago's Field Museum. Baby birds molt in order to lose their baby feathers and grow adult ones mature birds continue to molt about once a year. They're made of a protein called keratin, the same material as our fingernails and hair, and birds rely on them to fly, swim, camouflage, attract mates, stay warm, and protect against the sun's rays.īut feathers are complex structures that can't be repaired, so as a means of keeping them in good shape, birds shed their feathers and grow replacements in a process called molting.

Feathers are one of the key traits that all birds share.

Legend of dinosaurs and monster birds