A beautiful sunset closed out our lazy afternoon on Caribou Lake in the Boundary Waters Canoe Area Wilderness. Photo by Emily Stone.    

Chiiiiirrrrp! A single, loud noise rang through the dark.

My eyes popped open. “I don’t know what that was,” I whispered into the tent. “Well, it’s never good when the naturalist doesn’t know what made a noise,” joked my friend as they rolled over, sleeping bag rustling. While they fell back to sleep, I scrolled through a species list in my head.

Still, no luck in matching the sound to an animal I’d heard before. But wait, a few years ago I watched a couple videos of cheetahs chirping. Do other big cats ­– like cougars – ever chirp? I wondered.

A poem Mary Oliver wrote about seeing a bear track popped into my sleepy brain. “But not one of them [stories about people seeing bears] told what happened next – I mean, before whatever happens – How the distances light up, how the clouds are the most lovely shapes you have ever seen, how…Every leaf on the whole mountain is aflutter.”

And indeed, the thought of a cougar in the forest made it feel just a little more alive. Deciding not to worry about it, I also rolled over and let the steady rasp of beaver teeth from across the bay lull me to sleep. This was the first night of a quick weekend trip to the Boundary Waters, and I wanted to thoroughly enjoy my stay at the best campsite on Winchell Lake. We woke up to a white-shrouded dawn, but a stiff breeze chased the mist away while we ate breakfast on the beautiful rocky point.

The wind I’d listened to all night had returned in full force. Not wanting to linger and let the waves build even more, we packed up camp, loaded the canoe in the lee of our point, and struck out down the lake. Despite the lateness of the season, we spotted a few different solo loons bobbing in the waves, identifiable by their distinctive silhouette.

The sun’s glare off the choppy water made it difficult to tell if they were adults or juveniles, but either way they still had plenty of time to migrate before ice-up. Despite the headwind, we made good time on another big day of travel.

After a late lunch at our new campsite on Caribou Lake, we swam, and set up camp, and pulled out “Devotions” by Mary Oliver. “And to tell the truth I don't want to let go of the wrists of idleness, I don't want to sell my life for money, I don’t even want to come in out of the rain.”

The wind slackened with the setting sun, and we were soon enveloped in layers of darkness, nylon and down.

Chiiiiirrrrp! The mystery noise had followed us! But since we survived it the previous night, I assumed we’d survive again.

Sure enough, we woke to another white-shrouded dawn. Just off our campsite, the silhouette of a water bird faded in and out of the fog. Our visitor’s pointed bill and graceful neck were reminiscent of a loon, but their overall stature was more petite and delicate. Just like a loon, the bird thrust its face beneath the waves to peer beyond the surface glare. Seeing something tasty, it dove gracefully and then reappeared.

Then, chiiiiirrrrp! We looked at each other and laughed. Here was the source of our midnight mystery sound. By the general shape and size, I was pretty sure that the waterbird was a grebe.

Like loons, grebes dive to avoid danger and to catch fish, which they swallow head-first underwater, and have legs so far back on their bodies that they are awkward on land. Their newly hatched chicks also find refuge on Mom or Dad’s back. Unlike loons, grebes sometimes emit a single, loud chiiiiirrrrp!

Grebes also have lobed toes instead of webbed, and ingest a lot of their own feathers, which form two separate balls inside their stomach. Scientists think that the feathers may protect their digestive tract from sharp bones or fish spines. Grebes have more habitat flexibility than loons, since they are able to take off from smaller lakes, and they build up open, bowl-shaped nest structures on emergent plants or in shallow water, and therefore don’t have to rely on finding the perfect shoreline location.

Based on my Sibley Guide, my memories of the bird, fuzzy smartphone photos and encounters in previous years, I think this neighbor was a red-necked grebe. They breed mostly in Canada and Alaska, but can also be found on shallow lakes in northern Minnesota. While they migrate through the Great Lakes, grebes tend to spend the winter on the shallow estuaries and bays of northern New England.

The grebe had disappeared by the time we finished breakfast and packed up camp, but the thought of that little bird being the source of the mystery sound made me chuckle several times as we paddled out. With just one odd note, that grebe had created a permanent place for itself in my Boundary Waters memories.