The day ended up being as close to perfect as it could get.

The morning had been cold, with gusty winds chopping up the Atlantic and making warm clothes imperative. Throughout the day, though, the winds had moderated; when we reached protected coves, the bright sunshine made it feel downright summer-like.

Definitely not what I had expected to find out on Isle au Haut in October. We had come to observe harlequin ducks, but there were numerous other birds present throughout the weekend, some of which were a first for me.

We had reached a small, horseshoe-shaped cove with a pebble beach and long ledges upon which to sit and set up our spotting scopes. Out at the entrance to the cove, a dozen birds rocked gently with the waves, resting with their heads tucked into their feathers. Every once in a while, one would look around, perhaps shake out its wings, and settle again. They were red-necked grebes, and they looked as comfortable as we would be at home in our favorite living-room chairs. I imagined they were taking a much-anticipated rest after migrating from their breeding grounds in the western United States, Alaska, and Canada.

It was mid-October, about the time these birds would begin to appear. They’d spend the winter on the coastline from Newfoundland to North Carolina, resting and fattening up for their return trip in the spring. At that time they’ll begin to acquire their beautiful breeding plumage.

This grebe has a particularly elegant summer dress. The top of the head is crowned black; the face below its eye is white; and its neck is a warm cinnamon. The rest of its body is soft gray.

In autumn they trade their eye-catching costumes for the more practical and less costly winter wear: their necks fade to a dim reddish-brown, and the rest of their bodies are a more uniform gray.

Researchers have documented complex social behaviors among these birds. One, called the “discovery ceremony,” is used during courtship rituals; this is a highly ritualized display that establishes the bond between the pair. I’ve never actually seen it, but reading about it brings to mind an intricately choreographed ballet. The performance includes dives, pivots, lifts and face-to-face dancing. It ends with the birds rushing side by side along the surface of the water before they drift apart.

Tickets for this show come at a price; if we don’t take heed, we’ll not likely get many more chances to attend. Unfortunately, the list of grievances is long: toxic contaminants, entanglement in gill nets, degradation of habitat, and disturbance of nesting and roosting sites have all been implicated in this bird’s reduced success at breeding.

Once this show is over, it can never be brought back.

Chris Corio, a volunteer at Fields Pond Nature Center in Holden, can be reached at fieldspond@juno.com