By Tony Gazso, Interpretive Naturalist

For most of Ohio’s birds, August is an in-between time. The breeding season is done, but it’s not yet time to migrate back to wintering grounds. This is the time that most birds molt their feathers. The young are old enough to not need constant care by their parents, and there are still plenty of food sources available. With migration approaching, birds need a nice fresh set of feathers to make the long journey. Molting is something most of us know birds do, but not all birds do it at the same time or in the same way!
 
For most birds, like the local American robin, one complete molt occurs every year (some birds molt more often). You may have noticed the goldfinch at your feeders are bright yellow in summer, but a drabber yellow-brown in winter. They molt twice in a year, once in late fall where they molt into their basic (or nonbreeding) plumage, and then again into their alternate (or breeding) plumage in spring. Male mallards (like most ducks) molt into a basic plumage and take on the appearance of a female, losing their trademark green head. This is known as eclipse plumage. During this time, the ducks molt all of their flight feathers, leaving them mostly flightless for a period of a few weeks (this is actually where the term “sitting duck” comes from). In late fall/early winter they molt back into breeding plumage in preparation for courting.
 
For other birds, molting takes place throughout the first few years of their lives until adult plumage is reached. The male summer tanager goes through a number of partial molts until it reaches adult plumage. It’s only in its second year of life that the juvenile olive plumage gives way to the bright red adult plumage. During this transformation, birds are an interesting mix of colors (see below). Some birds take a longer period to reach adult plumage. A bald eagle may take five years of molting before they develop their signature look, while gulls don’t finish their juvenile molting cycle for four years. 

Summer tanager

All this molting business is why many of our avian visitors look so much more drab during fall migration than in spring, leading to difficulties in identification. It’s one of the reasons that fall migration is typically seen by birders as a more challenging time of year, but those up to the challenge are rewarded with birds that while subtle, are just as striking.