Feathers collected in a House Finch nest (Image: Brendan McGarry)

There you are, strolling 12th Ave, when you notice a swallow swoop down to the pavement ahead of you. Curious by an aerial creature landing on the ground, you stop. As the bird takes to the air again, it carries a fluffy white feather, bobbing on its way to a nearby nest. Feathers are so useful to birds that they not only are covered in them but scavenge them too. When it comes to vintage fashions, Capitol Hill birds recycle, too.

In daily life most of us don’t consider feathers much. Sure, we appreciate birds and feathers, we put them on things and we enjoy their beauty, but what do average people know about feathers? Very little. My hypothesis as to why: Those of you reading are all mammals.

Mammals have hair and hair provides thermal insulation, protection, and communication. However, besides fanning the flame of our narcissism, we don’t consider hair anything other than superficial (don’t freak out on me hair stylists). Feathers are abstract to the human body.

As I’m sure you have guessed, I think about feathers a lot. They almost all have the same basic design, which consists of a shaft, sprouting a series of branches called barbs, which have more branchings called barbules that link everything together like a zipper. Just like hair they need to be replaced regularly and they grow from a follicle. However, I’d never suggest hair trumps feathers in terms of diversity of form or function.

One can loosely lump a bird’s feathers in three categories:

• Flight feathers: the feathers of the wing or tail, which provide balance and propulsion to birds.
• Contour feathers: which cover most of the body, and are a shield from the element and help make a bird a sleek form.
• Down feathers: which are insulation and largely stay hidden, protected and unseen beneath the contour feathers. The first two categories are what carry pigmentation for display or camouflage and are more rigid than down. Rigidity is necessary for things such as protection from bodily damage and creating an air foil out of the wing for flight.

This time of year, feathers are obvious, because birds covet them just a little bit more. This is the breeding season for most bird species on Capitol Hill. Feathers display fitness (just one of several forms of communication that feathers provide), so birds want to look their finest. A male bird won’t get mates in beat down plumage, and feathers aren’t impervious to abrasion or UV damage. Just think about a robin crashing into the protection of a blackberry bush to evade a Cooper’s Hawk or a Glaucous-winged Gull being beaten down by sun-rays on the flat roof of an apartment building. These things lead to broken, ratty, or as us ornithologists say, abraded, feathers.

This male Black-headed Grosbeak has a lot of well worn feathers. (Image: Brendan McGarry)

So what is a bird to do? Surely you’ve noticed how brilliant even gulls and pigeons are this time or year. They get that way by molting.

Most birds replace a good majority if not all their feathers annually. Molting, the term for this replacement can be quite complex depending on the species, but for our purposes consider it an annual total replacement. This is no small undertaking either, because even a small songbird can have anywhere between 1,500 to 3,000 feathers. Just like our hair replacement, it usually doesn’t happen simultaneously (although ducks do replace all their flight feathers at once), because birds need to be able to fly and stay warm. For many of our birds, replacement happens post breeding season (sometimes in several doses), so that when spring comes around they look so fresh and so clean.

I’m sure you’ve seen a large bird like a Bald Eagle flying overhead, and noticed mirroring missing feathers in each wing. This is representative of how the vast majority of birds molt their feathers: sequentially, largely so that flight is not thrown off balance. A close call with a predator can find a bird missing feathers unevenly, left in the grasp of a cat say, and those can be replaced too, which is called adventitious molting.

Feathers are immensely more complex than what I’ve briefly described, but I wanted to take this month to consider the feathers we take from granted as a part of birds, as a wonder of evolution. Next time you find a discarded feather on the ground, realize there’s also a story there. Maybe it’s from a pigeon that nearly lost its life to a Peregrine Falcon high over the buildings of Pike and Pine, but escaped with only the loss of one feathers on the left wing, which you now hold in your hand. This feather is curved and stiff, to help create the airfoil that the pigeon relied on to avoid becoming lunch. Treat it as a totem or leave on the ground for someone else to find, either way it’s amazing.