It was a great surprise and delight to members of the birding world that a bird called a ruff showed up last week at Weskeag Marsh in Thomaston.

A ruff is a shorebird, or more specifically, a member of the sandpiper family. Its relatives include some birds you may know, like the lesser and greater yellowlegs, sanderlings, and spotted sandpipers. What makes the ruff exciting to birders in North America is that it is really a species of the Old World. Ruffs breed in northern Europe and Russia and winter in Africa and southern Asia. At least most of them do. A few are seen every year across North America, leading some to speculate over the years whether a small breeding population might occur in the Canadian or Alaskan Arctic. Indeed a single nest was found years ago in Alaska but the eggs were infertile; apparently no nests have been documented since then.

We have been lucky enough to see a couple of ruffs over the years, one down in Scarborough Marsh and one in Upstate New York. When we found a few hours to get down to Weskeag Marsh to see this ruff, we were not disappointed. Ruffs are so named because the males develop a ruff of feathers around the neck that they puff out when in breeding display. On the breeding grounds, male ruffs gather in groups called leks and display their neck ruffs to visiting females. The males sometimes attack each other as they display, hence their scientific species name of pugnax, as in our word “pugnacious.”

Male ruffs were known to come in two general types. One has a ruff that is very dark overall while the other has much white in the ruff. Researchers have found that the male ruffs with the darkest neck feathers are the kings of the leks while the ruffs with more white (some are almost all white) hang around the edges and are what researchers called “satellites.” Although the darker ruffs get the most matings, sometimes the satellites are able to sneak in and copulate with a female during the hubbub.

The sexual system was discovered just a few years ago to have an even greater twist. Researchers in the Netherlands were capturing and banding ruffs when they came across one that looked like a female but was much larger. They investigated further and found to their surprise that it was a male and that its testes were 25 times the size of normal males. A scientist named David Lank, who has maintained a captive research flock of ruffs at Simon Fraser University in British Columbia for many years, added some of these birds to his flock and began studying their behavior and genetics. Named “faeders” by the researchers—a name that means “father” in Old English—these birds slip under the radar screens of the aggressive displaying males and watch for opportunities to quickly sneak in to copulate with females that have crouched to allow a dominant male to mate with them. Interestingly, the researchers also discovered that these “faeders” have a large piece of DNA that somewhere back in evolutionary history got flipped upside down, apparently resulting in these males that look like females.

The ruff that we and many others enjoyed viewing in Weskeag Marsh looked like a traditional male with mostly dark feathers but with some white ones mixed in. If he makes it back to a lek, will he be a dominant male or a satellite? Is he headed back to Europe or to a small unknown breeding colony somewhere in Arctic Canada or Alaska? Will he be duped by a “faeder,” if he does get back to a lek?

We’ll never know, but time will tell, just as it has for generations of these fascinating birds.

Jeffrey V. Wells, Ph.D., is a Fellow of the Cornell Lab of Ornithology. Dr. Wells is one of the nation's leading bird experts and conservation biologists and author of the “Birder’s Conservation Handbook.” His grandfather, the late John Chase, was a columnist for the Boothbay Register for many years. Allison Childs Wells, formerly of the Cornell Lab of Ornithology, is a senior director at the Natural Resources Council of Maine, a nonprofit membership organization working statewide to protect the nature of Maine. Both are widely published natural history writers and are the authors of the book, “Maine’s Favorite Birds.”