Why do birds molt

Other birds such as Gray Flycatchers fly down to their tropical grounds first to wrap up the process there. Tree Swallows, meanwhile, may begin the swap up north, pause for migration, and then complete it after arriving at their wintering destinations. Many species also have a partial molt in late winter or spring, replacing their head and body feathers but not their flight feathers.

That's how a male Scarlet Tanager can switch to olive-green for the winter and back to luminous red for spring and summer. In general, smaller species replace all their feathers once, and will often replace some twice.

But the bigger the feather, the more taxing it is to replace it. That's why huge birds such as eagles and pelicans don't grow a new set of flight feathers each year; they restore individual primaries and secondaries on the wings in a staggered manner, taking multiple years to refresh. The juvenile stage refers to the period right after a fledgling leaves the nest.

For some species it lasts just a few days; for others it can take up to a year. Take the young Western Sandpiper , for example: It's crisp and clean-looking, almost like a recently detailed and upholstered car. After a bird goes through its first juvenile molt, it only changes feathers sequentially, which means it always has something old and something new on its body.

Wear is another way. In autumn, the gorgeous Snow Bunting molts into a buff and white plumage. But during the winter, those buffy tips rub away to reveal the underlying black and white breeding suit of the male. There's a small, but important difference between the two terms.

Wear is mechanical deterioration from flapping and environmental elements that causes the feather tips to fray. Generally, paler plumes wear more quickly because they lack melanin, a pigment that strengthens cells and protects them from damage. Fading, on the other hand, is a photochemical reaction, where UV radiation from the sun breaks down a feather's structure.

Lice and bacteria also contribute to feather loss. Due to this birds try to molt at times of year when there are not other activities occurring that need a lot of energy, such as building nests or migrating.

The two most common times of year for birds to molt is either before or after the breeding season. One complete molt per year — many birds only have one complete molt per year. There are many kinds of these birds, including chickadees, flycatchers, hawks, hummingbirds, swallows, and woodpeckers.

One complete molt and one partial molt per year — many other birds will molt all of their feathers after nesting. Then before the next breeding season, they will have a partial molt. At this time the males will grow bright colors in order to attract a mate. Birds with this approach to molting include buntings, tanagers, and warblers.

Two complete molts per year — The final approach, which only a few birds choose, it to make two complete molts every year. These birds tend to live in areas that put a lot of damage on their feathers and so they need to be fully replaced. Some of these birds include Marsh Wrens. The time it takes to finish molting is also always different.

The above source wrote, "note that molting periods cover a range as long as 4 months. The list includes keeping her in a warm temperate, feed her vitamin and protein rich seed, and covering her cage earlier at night, kind of like forcing her to go to bed. Even just from observation, I can tell how much molting helps. She looks very ugly while molting, but the feather grow back colorful and soft.

Kelsie, this is so interesting! I always knew they did this but I never knew WHY. My friend used to have one who would do this but her mom told us it's because the bird was under an immense amount of stress living in that house. Why do birds molt? About three years ago, I bought a pet parakeet.