The annual process of molting

If it’s late summer, it must be cicada screaming season. Having lived much of my life where they’re a regular part of the landscape, I’ve learned to turn them into background noise. But one of my international students recently exclaimed, “I didn’t expect summer to be so loud here!”  

The Blue Jays have also been pretty vocal for the last couple of weeks, their scolding cries a match even for the cicadas. I’ve been watching them at my feeders, dominating the other birds. (Except for the doves. The doves just sit stolidly in the feeder and stare the other birds down.) One of the Blue Jays is bald. And I mean totally bald. Without any feathers, its head looks rather like a lollipop stuck onto the body of a bird. It looks a lot smaller without its feathers, especially since it’s lacking its trademark Blue Jay crest. 

Unlike human hair, which never stops growing and requires trimming as the ends get brittle and split, feathers mature quickly and then stay put. Thus, as feathers wear out and fade, they have to be replaced. The exception is if a feather is pulled out or otherwise lost—then a replacement will grow in pretty quickly.

Most birds molt as they grow from their juvenile to their adult plumage. You might have noticed this with robins. Young robins have white patches on their faces and speckled breasts, growing darker heads and their red breasts as they mature. Young birds can be mistaken for entirely different species from adults. Take a look at gulls, for example, which have distinct feathers for each of several years until they finally develop their adult coloring.  

Molting is an annual or semiannual process for many birds, and molting might involve changing all or only some feathers. Our Blue Jays molt once annually; hence their late-summer baldness. Canada Geese migrate in mid-summer to lakes where they are relatively protected from land predators as they can’t fly as they molt.

Some birds molt partially as they get ready for breeding season. The bright warblers that we welcome every spring are much drabber as they return during fall migration. This time of year, they’re a lot harder to tell apart, as acknowledged in my Peterson’s Field Guide by a section called “Confusing Fall Warblers.” 

And then there’s this mystery I solved while I was researching this column. I haven’t seen European Starlings in my yard in several weeks. Today they were back, but looking much more brownish-gray than they did earlier in the season. According to my Handbook of Bird Biology from Cornell Lab of Ornithology, this is because the tips of their newly-molted feathers are much lighter. Over the winter, these tips will wear off, exposing the beautiful iridescent colors that make me forgive them for being such pests at my feeders. 

Male Northern Cardinals will do much the same thing. Look for them to get redder as the winter wears on and be at their brightest in March, just when they start singing their cheer, cheer, cheer song—loudly—to tell other cardinals that this is their territory and to let us humans know that spring will be here soon. 

Of course, it’s the cicadas that have the most spectacular molt. Once they emerge in late summer, they leave their exoskeletons all over the place as they transform into adults practically the size of hummingbirds. Who then proceed to scream us from summer to autumn.