Identify birds when their feathers are wet

Feather colors and patterns provide some of the most important clues we have for identifying birds and are usually quite reliable. Only a few things change the appearance of feathers. They wear out and fade over time. They can be temporarily out of place, disrupting the typical color pattern and sometimes revealing an unexpected grayish or whitish color from the exposed feather bases.

Feathers can also be stained or discolored by external substances, and the most common of these is plain water. Feathers are water repellent and water generally rolls off (like water off a duck’s back), leaving the feather unaffected. When the feathers are subjected to a real spray, some of the water sticks to the feather and they become wet. This most often happens when water is somehow squeezed into the feathers: sparrows pushing through wet grass, doves exposed to a heavy prolonged rain shower, or warblers taking a bath.

The surface of a dry feather is a fine mesh of reflective surfaces. When water saturates this mesh, the appearance becomes darker and the barbs that form the rounded tip of a normal feather are gathered into tufts, forming an irregular, pointed shape.

Once you’ve seen a few wet birds, it’s usually easy to recognize the condition and take it into account when working on an identification. However, if you don’t expect it or realize that a bird is wet, it can be quite confusing. Because the feathers on a bird’s body are arranged in an organized pattern, the dark, pointed tips of wet feathers often line up to form what appear to be dark streaks, dark lines around the face, or other patterns. And when the barbs at the tip of a feather clump together, it can expose the pale gray or whitish base of the feather below, which is normally concealed by the broad, rounded tip of a dry feather.

The solution to this challenge, like so many other bird identification challenges, is to be aware of the possibility, examine multiple characteristics, and keep an open mind. With practice, it will become second nature.

This article first appeared in the July/August 2021 issue of BirdWatching magazine.

Watch a PBS video on how water runs off a duck’s back