The middle and late parts of summer are when a little-noticed but very interesting change takes place in the Ozarks’ bird world.
Take a close look at birds at your feeders or around your home, and you might notice they look a little different than they did in spring. The same species (cardinals, robins, etc.) are still around, but their colors aren’t as vibrant. In some cases, their feathers might look a bit rougher or more disheveled than they were a couple of months ago.
Don’t worry. Chances are, your backyard birds aren’t sick. They’re simply going through a normal process that, for most bird species, is an annual occurrence — molting. Molting is a word most of us have heard, but many people aren’t quite sure what it means.
Molting is the process through which birds replace their feathers. Broken and worn feathers cannot be repaired. Instead, birds systematically drop feathers and replace them with new ones. Most birds molt annually, though there is some variation between species. Frequency of molt can be affected by age, seasonal changes, hours of daylight and breeding activity.
The replacement of a bird’s feathers might seem like an inconsequential event to humans, but if you’re a bird, your life depends on it. One benefit of having a good set of feathers is protection. Feathers protect a bird from the sun’s hot rays, from rain and from injury to their delicate skin. They also assist in flight, swimming and other actions that are specific to some bird species.
In spring, brightly colored feathers are needed by males of some species for courtship purposes. Feathers also have the ability to create trapped air pockets that serve as insulation in cold weather. Feather replacement also helps control lice living among a bird’s feathers.
Middle to late summer is when many bird species molt because it’s a time of preparation. Some bird species are getting ready for long migratory trips. Other species that are year-round residents are starting to prepare for the arrival of the cooler temperatures of fall and winter. Either way, it’s imperative to a bird’s survival to have a fresh coat of feathers in the near future.
Molting can last from several weeks up to three months. Some species, such as Canada geese, become flightless during molt. Goldfinches do a drastic color change, going from a bright yellow to a drab olive-green. Most birds, though, conduct business as usual throughout their molting period and undergo noticeable, but relatively minor, appearance changes.
In most songbirds, molting begins with the loss of their inner-most feathers (called secondary feathers). Feathers are lost and replaced in a process gradual enough to allow the bird to continue with normal feeding and flight activities. The final replacement comes to the large flight feathers that are on a bird’s wing farthest away from the main body (called the primaries).
The molting period is a physically taxing time for a bird because the production of new feathers requires extra energy. It’s also a period when a bird is more susceptible to disease because of its increased energy use.
In spite of these higher risks, humans shouldn’t spend much time worrying about molting birds. Birds have been molting successfully without human intervention for millions of years. Keeping feeders filled and providing a relatively clean water source for birds to bathe in are two of the best things people can do to help make molting easier for their backyard birds.
Information about birds can be found at the Missouri Department of Conservation’s Southwest Regional Office in Springfield and at the Springfield Conservation Nature Center. Information about birds also can be found at missouriconservation.org.
Francis Skalicky is the media specialist for the Missouri Department of Conservation's Southwest Region. For more information about conservation issues, call (417) 895-6880.