Bird migration

The Case of the Missing Spectacles

Migration mysteries are not only a thing of the past. In fact, we at Terra are driven by the ongoing questions about migration that are yet to be solved. And that brings us to a modern-day mystery that was solved relatively recently: the Case of the Missing Spectacles.

Migration around the Arctic Circle

If you asked the average person today what we know about animal migration, they might say that most of the animals — at least the big ones — have been accounted for. Science surely knows the migratory habits of all birds the size of geese. But if that was your answer in 1994, you’d be wrong.

In spite of our advanced technology, places like the Arctic Circle pose challenges to researchers that can be impossible to overcome. Deep cold, days without sunlight, and deadly storms all make studying the creatures of the far north especially difficult. The fact that any creature survives in such menacing conditions is a miracle of nature, and no animal is so miraculous as the Spectacled Eider. 

Tracking Spectacled Eiders

Eiders are sea ducks, large birds that spend much of their time in salt water, often feeding on clams and other invertebrates. Spectacled Eiders are one of the northernmost version of Eiders, and can be seen in the summer Alaska and northern Siberia nesting near bodies of water in grassy wetlands. Their name comes from their striking face plumage, which makes them look like their wearing oversized glasses.

And in winter? Nobody knows. At least nobody knew, until some very determined researchers went to Alaska in summer to solve the mystery. Working from a tent in the Y-K Delta, they attached tracking devices to twenty-six Spectacled Eiders, hoping to trace the route to their secret wintering grounds when the seasons turned. Unfortunately for the researchers, the batteries in the trackers failed early, apparently due to the high body temperature of the birds. After that, the birds disappeared again without a trace, and the mystery was as unsolvable as ever.

Life on the ocean

Or so they thought. Six months after the transmitters had been attached, one transmitter sent out a single signal. It was undoubtedly some kind of technical error, because the beep came from the frozen Bering Sea, 120 miles from any point of land. Nonetheless, a couple of biologists studying the birds went to look.

Flying over the icy ocean in a small prop plane, all they could see was polar bear tracks and snow. One of the team said, “The overcast sky had merged with an endless expanse of ice, and there was no visible horizon — just white in every direction, as if we were flying inside a light bulb”. As their fuel began to get low, a small brown spot appeared on the horizon.

And then they saw it. Fifty-thousand Spectacled Eiders, all within 20 miles of each other, jammed into cracks and holes in the ice, thriving in some of the harshest conditions on earth. In fact, it’s likely that the majority of the worlds Spectacled Eider population winters in this god-forsaken area, feeding on clams and other invertebrates through the winter, their thick feather coats keeping them warm, until it’s breeding season and they make the brief return to the land. Males, in fact, spend 11 months of the year on the ocean. These eider are among the most perfectly adapted survivalists on the planet, and it was only perseverance, and luck, that gave us a glimpse into their incredible lives.