Ah, spring is here at last. Snowbanks are shrinking fast, creating rivulets and slushy pools of water. These are a prime attraction to birds at this time of year.

On one recent day, a mixed flock of pine siskins, goldfinches, and house finches sat on the bare limbs, busily preening and fluffing their feathers. I sat quietly for a few minutes, and the birds, apparently deciding the coast was clear, flew down to continue what I had interrupted – the serious business of bathing.

They were so comical as they dipped their bodies into the water, shaking their feathers and flicking their wings and tails with each dousing.

Some of the birds were a little more restrained, choosing the shallow rivulets of water to bathe in – it seemed they were barely touching the water. Others practically immersed themselves in small, slushy puddles. These enthusiastic birds dipped the entire front half of their bodies under, flipping their heads up to throw the water over their backs.

As funny as they were, the care and maintenance of their feathers is of extreme importance. Their very lives depend on it – not only for flight, but also for insulation and waterproofing.

There are five types of feathers, and each has a different form and function.

First are the contour feathers, which are the typical body and flight feathers. These feathers are made by interlocking structures (think of these structures as resembling a zipper or Velcro), which form a vane. The bottom of the vane, which is closest to the skin, is soft, loose and downy. This provides excellent thermal insulation. The top part of the vane provides an airfoil, sheds water, protects the downy undercoat and reflects or absorbs solar radiation.

Semiplumes are softer and looser, not quite as stiff, and are hidden underneath the contour feathers. They also provide thermal insulation, as well as defining the shape of the bird’s body.

Down feathers are extremely fine, soft and loose. They provide insulation for all bird species. A particular type of down feather, called the powder-down feather, produces a fine, white powder composed of keratin granules. This powder is completely resistant to water and is shed throughout the plumage, providing an effective waterproof shield.

Bristles are extremely stiff structures located mostly around the bill, the eyes, on the head and on the toes of some birds. These act as screening agents or as sense organs, enabling birds to capture flying insects. They are most visible around the beaks of flycatchers, such as the eastern phoebe, or the so-called nightjars, such as the common nighthawk.

Finally, there are the filoplumes. These are fine and hairlike, sometimes growing above the contour feathers and adding to the appearance of the bird. Most often they are hidden. They are a refined sensory system, providing information on the positioning of other feathers for flight, display, bathing or insulation.

Birds bathe and preen to remove debris and parasites, and also to ensure that all the feathers fit together properly, providing maximum protection and insulation. Installing birdbaths in your yard will go a long way in helping the birds maintain healthy feathers, as well as providing unfrozen water to drink in the winter.

Chris Corio is a volunteer at Fields Pond Nature Center. She can be reached at fieldspond@juno.com.