Inspired by the recent sighting of at least two king rails in Wells, I am devoting this column to one of the least appreciated groups of birds in Maine, the rails. Our rails are marsh birds, infrequently seen but often heard.

Rails belong to the avian family rallidae, a group that also includes the coots. Coots are duck-like in their behavior and by no means secretive. I’ll stick to the rails in this column.

Rails have short, rounded wings. Despite the meager surface area of their wings, many rails are migratory. Lots of oceanic islands have been colonized by these unlikely migrants. Once on an island, rails speciate to form an endemic species. Alas, most of these endemic island rails are extinct, primarily due to direct or indirect effects of humans.

Rails are predators, preying on insects, spiders, crayfish, snails, other invertebrates, small fish and even seeds. Bill length varies quite a bit between species but always serves as an effective forceps to grab single prey items. Rails have long toes, allowing the birds to walk through muddy areas without sinking into the mire.

Rails are laterally compressed. Imagine putting your hands on either side of a balloon and pressing in. The balloon becomes thin and tall. This body shape in rails certainly helps them move through the dense vegetation of a cattail marsh or a salt marsh.

My wife and I had an argument about the derivation of the term “thin as a rail.” My claim was the phrase refers to the thin width of one of these marsh birds. My wife claimed the reference is to the split logs used to make fences. We decided to enlist the aid of a Colby reference library that disabused me of my interpretation. Nevertheless, thin as a rail fits for these birds.

We have five types of rails in the state. Two of them, the Virginia rail and the sora, are common in the summer throughout Maine. Clapper rails, king rails and yellow rails are rare birds for the state.

The Virginia rail is a handsome bird, 9 to 10 inches long. A rusty breast, olive-brown dorsal surface, flanks striped with black and white, a gray cheek patch and a long, red bill make these birds sharp dressers.

Alas, their secretive nature means a fleeting glimpse is all you can expect. Their presence in a marsh is usually given away by their insistent clicking vocalizations, as well as pig-like grunting.

Our other regular rail is the sora. A bit smaller than a Virginia rail, a sora has a gray neck and breast, a black face and a short, bright yellow bill. The common name comes from a rendering of one of its vocalizations, a two-note whistle. It also gives a downward spiraling whinny. The twilight hours are best for hearing these remarkable calls.

On May 10, Bri Benvenuti photographed a king rail along Eldridge Road in Wells. Other birders learned of this rail on June 7, and birders have been flocking to Wells to see this local rarity. We know there are at least two present. This sighting represents the seventh record of the species in Maine and the first in 20 years.

As the name suggests, king rails are large, about 15 inches long. Their mostly cinnamon feathering camouflages them well. Fortunately they like to forage along the water’s edge, so they are often seen along the marsh edge.

Clapper rails are very similar to king rails. Identification requires a good look at the edges of the contour feathers (buff in king rail, gray in clapper). That’s a tough task in such secretive birds.

We have six records from Maine, the latest being from 1973 in Wells and last September in Scarborough.

Finally, the small yellow rail is probably more common than we know. They seem to migrate through Maine from mid-September through mid-November.

Herb Wilson teaches ornithology and other biology courses at Colby College. He welcomes reader comments and questions at:

whwilson@colby.edu