Summer Molt - Iowa Wildlife Federation

Summer Molt

Photography courtesy of Lowell Washburn, all rights reserved.

Brightly colored and sculpted to a fault, the cardinal is one of my favorite backyard birds.  But the bird currently sitting at my feeder did little to fit that description.  By contrast, this cardinal appeared dull and disheveled.  Happens every summer.  Having raised their latest crop of youngsters, adult parents began losing and replacing their feathers one by one.  It’s called the annual molt.  

Losing His Cool – Although appearing disheveled today, this molting cardinal will be shiny as a new penny by late fall.

A time of complete transition, the summer molt is not unique to backyard cardinals.  All birds undergo some fashion of an annual change of feathers.  Feathers, like all living things, grow, age, and die.  For birds to survive, feathers need to be replaced.  But although all birds molt, the individual strategies are as widely varied as the birds themselves.  Most birds undergo their first complete molt when transitioning from juvenile to adult plumage during their first full year of life.  But others, such as bald eagles, may require several years of partial molt before finally attaining their stunning, fully adult plumage.  Indigo buntings, red-tails, Cooper’s hawks, and orioles complete their transitions in two to three seasons.     

Molting red-tail – A single remaining, barred tail feather identifies this molting red-tail as a yearling well on its way to attaining adult plumage.  Unlike waterfowl, molting raptors never lose their ability to fly, an essential skill for conducting daily hunting forays.

Waterfowl [ducks, geese, and swans] have the most dramatic molt of all birds.  Instead of dropping last year’s feathers a few at a time, they shed them by the dozens.  The annual molt is most noticeable in the males [drakes] that change, seemingly overnight, from the flamboyant gaudiness of spring plumage to the drab and subdued [eclipse] plumage of summer.  The waterfowls’ molt of primary wing feathers is so rapid and so complete that adults become totally flightless while awaiting the arrival of new plumage.  This flightless period occurs during mid to late summer when natural wetland foods are most abundant and emergent escape cover is at its thickest.  In spite of losing their ability to fly; species like mallards, teal, wood ducks, and Canada geese are still able to successfully guard and raise their broods.  It’s a well-timed strategy that allows grounded fowl and their growing youngsters to survive the obvious perils that accompany temporary flightlessness.

Flightless Canada – Canada geese molt their primary wing feathers so rapidly that adults become totally flightless.  This flightless period occurs during mid to late summer when natural wetland foods are most abundant and emergent escape cover is thickest.

For most bird species, the annual molt is a much more conservative and gradual process than that of local web-foots.  And although many birds such as jays, red-tailed hawks, and chickadees may attain an extremely ragged appearance, the birds never lose their ability to fly; a critical skill needed by most species for hunting and delivering food to nests of growing young.

Although many of our backyard birds may appear ragged and moth eaten today, the seasons pass quickly.  Before you know it, the annual molt will be complete, and our favorite species will once again become the brightly colored showoffs that we love to watch.

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