A Northwoods Almanac for 9/16-29, 2011
Life in a Northern Winter: The Ultimate Survivor Show
While the main order of business for plants and animals in summer is reproduction – courting, mating, birthing, and raising young – it’s another story altogether in autumn. A different intensity now replaces summer’s fecundity. From an animal or plant perspective, autumn is likely experienced as simply a prelude to an Armageddon that we call winter. Here in northern Wisconsin, plants and animals have only three options available to them to survive winter: migrate, adapt, or die. “MAD” serves as the perfect acronym, and it does seem mad to try to live through a winter that averages 150 days of below-freezing temperatures and 140 days of ice and snow cover. Add in greatly diminished food supplies and extremes of weather that would seem impossible to withstand, and winter takes on more than a patina of dread.
How do plants and animals make it to spring? Every organism has its own remarkable story, its own set of amazing adaptations that range from the extremes of hibernation to eating nearly 50% of one’s own body weight daily in order to get to tomorrow.
Thus, there’s more going on in winter than meets the eye, and autumn is all about the necessary preparation for it. For birds, flight avails them of southern climes. Of our 226 confirmed breeding bird species in Wisconsin, over 130 migrate to Central or South America where pina coladas replace antifreeze. Their intent is to live in a perpetual summer – maybe they sing continuously their own version of George Gershwin’s “Summertime and the Living is Easy”. However, their migratory flights are no romp in the park – they must skirt a perpetual array of hazards from predators to storms to lack of food to electrical wires. Despite the birds’ amazing flight and navigational capabilities, most won’t make it back, a resounding testimony to their drive to escape the even greater dangers of a winter lived in northern Wisconsin.
We humans, of course, also “migrate,” some to Florida and Arizona, but most of us move to an indoor world warmed by furnaces, lit by electricity, and supplied by food from far southern regions via trade and a web of transportation. Our “migration” hazards are of a different order – the use of vast quantities of various fuels from thousands of miles away to supply our every need for six months or more. But that lead us into a political story, a moral dilemma and spiritual imperative that is beyond the reach of this column. It is enough now to marvel at the changes going on around us in the natural world, where survival relies on responding to signs of natural change.
Wild Cranberries
Every September for the last decade I’ve led a hike for artists who were selected to be in the world-renowned Birds in Art exhibit at the Leigh Yawkey Woodson Museum in Wausau. Last weekend I led a group again, this time on the Raven Nature Trail south of Woodruff. Once section of the trail crosses a bog, and I was able to find enough wild cranberries for most of the folks to sample on the hike. Despite their tartness, the cranberries were a hit!
The wild cranberry (Vaccinium oxycoccus) are attached to a slender, creeping stem that is hard to spot. The alternate, simple leaves are tiny, less than 3/8" long, while the red, often speckled berries are twice the length of the leaves, a surprisingly large fruit from such a tiny plant.
The cranberries spread over the bog mat by sending out long stems that root at the joints and begin another clonal plant. The leaves, like most bog plants, are evergreen,
and though the berries taste sour, making the eyes squint a bit with each bite, they make fine sauces and jams.
Wildlife seem to ignore the berries for the most part, and the fruits may last through the winter, though chipmunks, ruffed and sharptail grouse, and mourning doves eat a few.
The berries keep well (must be all the tartness that does it). Early settlers picked their share, and before them the Indians used them in trade. A 1762 writing stated, "They are excellent against the scurvy." The Ojibwe made a tea of the leaves to cure nausea.
Cranberries got their name from the Old German "Kranbere", or crane-berry, in reference to the long protruding stamens in their flowers that bear a resemblance (use ample imagination) to the beak of a crane. Oxycoccus comes from oxy meaning "sharp, keen, or acid", and coccus meaning "berry".
Sugar Maple Seeds
I noticed a bountiful crop of seeds on some sugar maples this week, and they’ll be falling soon. Sugar maples produce enormous quantities of seeds, varying in one 12-year study from 40,000 per acre to over 5 million per acre on the same site. Since maple seeds are shed at the same time as leaf fall, they receive the advantage of being buried in the nutrient rich leaf litter. The result is huge numbers of young seedlings occupying the forest floor, commonly 20,000 per acre. One researcher estimated that 4,000 young seedlings spring up every year under one mature sugar maple, or a total of 1,400,000 seedlings in the life of a 350-year-old tree. Out of those only about 70,000 last into the second year; maybe 1,400 live to 10 years; perhaps 35 grow over 20' tall; two may reach 150 years old; and one may be lucky enough to reach old age.
Leaf Change
It sure seems like autumn leaf color is taking its sweet time this fall. To view a statewide fall color report so you know when and where to go leaf peeping, go to www.travelwisconsin.com/fallcolor_report.aspx#/Report.
Porcupine Dispersal
In the last few weeks, I’ve noticed an inordinate number of road-killed porcupines. The most likely reason is that juvenile porcupines disperse in the fall when the mother stops lactating and begins to come into estrus. Since porcupines court and mate as early as September (the peak of breeding season is in October and November), it makes sense that we usually see an increase in porcupines along roadsides in the fall. Their dispersal is a wired-in behavior to limit inbreeding and resource competition. Mostly juvenile females disperse, while juvenile males typically remain on their natal territory.
Adult males also disperse in the fall if they’re unable to breed due to competition from another male – being a bachelor porcupine is not a desirable life. Average dispersal distance in one study was about 2 miles, so they’re not wandering great distances.
Once bred, the female begins a 205 to 217 day gestation period, and then bears a single young, rarely two. Weaning doesn’t usually occur until three months of age, and by six months of age, the porcupette is independent.
Porcupines begin breeding at 15 to 18 months, and their potential life span is 10 years.
Jam!
It’s the time of year to be making jams and jellies if you haven’t already been making them from strawberries, blueberries, blackberries, et al. The elderberries in our yard are ripe and ready, so we’ll be jamming soon. But if you’re unable to make your own jam, or just want to buy some unusual varieties, you need to know of a great source for jams made in the Keweenaw Peninsula – the Jampot, operated by the Society of St. John near Eagle Harbor (www.societystjohn.com/store). Their selection is amazing. Whenever we lead a hawk-watch trip to Copper Harbor in May, this is a required stop along the way, and often nearly as big a hit as a good flight of hawks!
Sense of Smell in Birds
Turkey vultures seem to be on the increase in the Northwoods, and in the course of discussing their population, I’m often asked about their sense of smell and the sense of smell in birds in general. Well, birds have a very poor sense of smell, perhaps, say some laboratory studies, in the range of one-third to two-thirds that of fishes and mammals. As a group, they have very small olfactory lobes in their brains, which by inference indicates a weak ability to smell.
But a few birds clearly have a well-developed sense of smell, one of which is the turkey vulture. Their olfactory organs are unusually well developed for a bird – according to one study, they are the ninth largest of 108 avian species. Their ability to locate food by smell has been repeatedly demonstrated experimentally and has been supported by many anecdotal observations. For instance, in various studies, turkey vultures have been caught in traps well hidden from view or baited with scent only; they often find concealed food by approaching from downwind; they’re attracted to mushrooms and flowers with carrion-like fragrance. The odorants they use as cues are unclear, but positive results for ethyl mercaptan have been noted. This is the same gas that natural-gas companies introduced into pipelines as an odorant, and the gas companies have discovered leaks where turkey vultures were found circling or on the ground.
One other Wisconsin species appears to have a highly developed olfactory process. Virginia rails have a large number of nasal glands and ducts in their olfactory chamber, and a large olfactory bulb in their brain; thus they probably have a keen sense of smell, but no studies have been conducted to prove this out.
A little west of us, black-billed magpies often cover food caches with a stone or leaf, and then apparently remember many of their cache sites by sight or smell. In field test of their olfactory abilities, magpies were able to recover significantly more hidden caches of raisins and suet if they had been scented in cod liver oil than control caches. The ability to use scent probably enables magpies to find and eat each other’s caches, and “cache kleptoparasitism” (what a great term!) has been observed in unrelated birds near a roadkill, and by mates within a territory.
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