Why Are Some Birds Bald?
A Bare Head is Normal for Some Bird Species, Unusual for Others
Jan 31, 2008 Rosemary Drisdelle
Most people, except perhaps turkey farmers, think of birds as being feathered all over, but there are birds with no feathers on their heads—either because that’s normal for the species, or because something has made all their head feathers fall out at the same time.
Birds that are Naturally Bald
Quite a few species of birds normally have no feathers on their heads. A few familiar ones are turkeys, vultures, and some species of storks and ibis. In the case of vultures, it’s generally thought that having no feathers on the head is preferable for a bird that eats carrion: head feathers would get fouled with decomposing material from carcasses and be difficult to clean.
In other birds with bald heads the skin replaces bright plumage: exposed skin is typically very brightly colored and it may be adorned with bumps, wattles, or other features. In some species the skin colour can change rapidly. All of this is thought to be important in display and courtship behavior.
Meanwhile, the familiar Bald Eagle is not bald at all—adults have white feathers covering their heads (bald is derived from an outdated English term meaning ‘white head’ or ‘white patch’).
Patches of Exposed Skin on Birds’ Heads
Patches of brightly coloured skin on birds’ faces and heads are very common. Like the bald colourful heads of turkeys these skin patches are usually ornamental and play a role in courtship. In some species, however, such as tropical penguins, bare skin plays an important role in shedding excess heat.
Bald Molting Birds
For most birds, molting is a process where a few feathers are lost and replaced at a time—the bird looks a little scruffy, but it always has a covering of feathers. In some species, however, particularly Blue Jays, cardinals, and possibly grackles, a few individuals seem to lose all the feathers on their heads at once, resulting in a very odd looking bird.
When birds become bald this way, it’s temporary: new feathers soon grow and the bird looks normal once more. Some bird experts believe this is a rare (and insignificant), molting pattern seen in particular individuals year after year. Others wonder if the phenomenon is caused by a health problem.
Bald Birds with Health Problems
Ornithologists have speculated that bald birds (those that are not naturally bald) may have health problems such as malnutrition, mite infestation, or some unidentified disease. None of these things have ever been proven to be the cause, however. These explanations probably account for a small percentage of bald birds.
Sources:
Bald Birds. Project Feeder Watch
Firefly Encyclopedia of Birds. Perrins, Christopher ed. Buffalo: Firefly Books, 2003
Northern Bald Ibis
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Northern Bald Ibis (Waldrap)
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