The thick carpet of pine needles felt springy and dry under the trees. Patches of sunlight kindled warm fragrances to tickle our noses. On the wooden wildlife observation deck, though, an inch or so of soggy snow—not fit for November—dripped steadily through the planks. Skims of ice only clung to the shallowest pools in the marsh, and in one bay, a column of mist rose from the dark water. Although it was just past noon, the low angle of the sun illuminated the swirling cloud in soft light as it danced in partnership with the breeze.
Abruptly, a raucous “kreh kreh kreh” erupted from the edge of the pines. My first thought was a merlin – a small falcon with a big voice. But merlins head south in September, and the peak of their migration is long past. I peered into the pine boughs where the sound originated, and caught a glimpse of a gray-colored bird a little bigger than a robin. As soon as I spotted it, the bird flew. Our visitor didn’t high-tail it into the bushes, though, it made an unhurried swoop toward us on downward angled wings, and perched in a nearby birch. There was no mistaking that flight pattern; the alarmist was a gray jay.
The habitat range of these non-migratory birds--once called Canada jays—encompasses most of Canada up to tree line, and scoots just under the nose of Lake Superior like a mustache. Here at the southern edge of their range they aren’t very common. Usually I have my annual encounter with a “camp robber” in the Boundary Waters or Sax-Zim Bog north of Duluth.
Why do they live so far north? Gray jays seem to be dependent on two things: a strong presence of certain tree species (black and white spruce and jack pine in our area), and cold temperatures. Both requirements relate to their food storage method.
In order to survive the long, bitterly cold winters in their range, gray jays must put up food all summer and fall. They accomplish this by coating mouthfuls of food in sticky saliva, then gluing the boluses in tree crevices, under lichens, in evergreen needles, and behind the flaky bark of their preferred tree species. A gray jay may hide 1,000 separate caches of food in a single, 17-hour day. “Scatter-hoarding” is the technical term for this technique. “Gray jays have a memory like a Vegas card counter,” writes Joe Rankin in Northern Woodlands magazine, referring to the fact that the jays seem to be able to retrieve 80 percent of their food-filled saliva balls.
At least a portion of the lost 20 percent is due to spoilage. Some boreal tree species may contribute antibacterial compounds that help the food stored under their bark stay fresh. But that’s not enough. Cold temperatures in the gray jay’s preferred habitats are necessary to prevent cached food, even chunks of meat, from spoiling.
On this lovely, sunny, warm day in November, the vulnerability of these southernmost gray jays was driven home. Their refrigerator is broken. This is the warmest fall on record, and that doesn’t bode well for the longevity of cached meat and other food. Their reproductive rates may suffer, since gray jays nest in late winter, and feed nestlings from their caches. A study by the University of Guelph in Ontario confirmed that gray jays are food-limited during the breeding season. The researchers connected this with warmer fall temperatures allowing food to spoil and a 50% decline in numbers of gray jays in Algonquin Provincial Park over the past three decades.
It’s not because they’re picky eaters, either. Gray jays are opportunistic omnivores, and they consume everything from small mammals, nestling birds, carrion, and arthropods to fungi, fruits, and seeds. They have been observed picking engorged winter ticks off the backs of moose. Anyone who has camped within their range knows that these “camp robbers” are not shy about snatching up a crust of bread off the picnic table, or nabbing a marshmallow before it can become a s’more.
Our lack of food made us boring to the “camp robber” who came to investigate. He scrutinized us for only a minute before flying off. Since gray jays mate for life and stick together year-round, I would guess that this solo guy is a bachelor, and probably a young of the year. Even without the broken refrigerator, his is a tough lot.
In early June, the two-month-old chicks begin an intense sibling rivalry. Only one dominant juvenile gets to stay with its parents, after driving the rest of the young away. These “stayers” gets access to their parents’ food caches and mentorship, in exchange for helping to raise little brothers and sisters the next summer. Even with the help, they still face a 52 percent mortality rate. The “leavers” that get kicked out may be able to volunteer their nanny services to an unrelated pair currently without chicks of their own. Or they may simply perish during the hungry winter. Leavers experience an astounding 85 percent mortality rate, while stayers only die about half the time.
As we gazed over the wetlands and pine forests, the midday sun warmed my face and the unseasonable weather made me sigh. That lonely jay had every right to scold us for breaking his refrigerator.
[Columnist Emily Stone is publishing a book of her Natural Connections articles as a fundraiser for youth programming at the Cable Natural History Museum. Since kids are often the inspiration for her articles, the Museum is conducting an art contest for local students to illustrate each of the 52+ chapters. The hope is that students will read some chapters, learn something about the plants and animals in those chapters, do a little more research on their own, and then create a black-and-white line drawing based on their research. The best and most relevant illustration for each chapter will be included in the book. Please share this opportunity with any kids in your life! Entry forms can be found at:cablemuseum.org/programs-and-events/.]
|Gray jays are charismatic camp robbers that live close to their southern limits in Northern Wisconsin. Photo by Skip Perkins.|