Nature Notes: Harvest Time
Early autumn, and the living is easy, as easy as it gets in the natural world at our northern latitude. The heat and drought conditions of summer are gone, and the deprivation of winter has not arrived. This is a time of plenty for most wildlife and they are making the most of it. Across the animal kingdom there are a fascinating range of behaviors to boost the chances of survival through the long winter months. Let’s check in with some of our favorite species to see what they are up to now.
If you have been watching the night skies lately, you have seen some wonderful moons, including the full moon today on October 9. At 6 AM today that moon was hanging just over the horizon when I awoke, with an orange glow as it sank from sight. While September’s full moon is often referred to as the harvest moon, October’s full moon was known by indigenous people as the hunter moon. This was the time of year when game animals were at their peak, representing prime protein for the tribe’s hunters. Of course, humans are not the only hunter/gatherers in the field right now. Almost every creature from tiny insects to the largest mammals are diligently searching for their next meal and often setting aside some supplies for the cold months to come.
A recent trip to Saskatchewan and Manitoba gave me the opportunity to observe vast flocks of ducks, geese and sandhill cranes as they began the long journey from their breeding grounds in the tundra and boreal regions of northern Canada. The first major rest stop on the journey is the vast grain belt of those two provinces, where you can drive for hours in a seemingly endless swath of canola, wheat, peas, soy and more. Even the best combines drop a surprising volume of grain on the ground and this becomes a buffet for all those hungry waterfowl. In one field I was awed by the sight of at least 10,000 snow geese stooping in to share the bounty. Those hungry birds will make many more stops on their way to the southern US, using agricultural lands and protected wetlands for rest and recharging.
Another thrill on my trip was seeing hundreds of raptors including hawks, owls, eagles and falcons of all sorts. All those grain fields attract a huge number of small mammals and birds, creating a prime opportunity for winged predators. In rural areas it seemed like every half mile I would spot another Swainson’s hawk, a kestrel or if I was lucky, a prairie falcon, sitting on a post or power line looking for a meal. Many of those raptors will use favorable tail winds to head south to their winter haunts, in some cases deep into South America, so they must build their energy reserves for the long trip.
If you have ever studied an active beaver pond in the autumn, you probably witnessed the big rodents working on their dam to keep it in prime condition. The water in the pond behind the dam is critical to protect the beavers during winter when ice creates a cap, sealing the beavers into the pond for months, and keeping predators at bay. Beavers pack mud on top of their houses that when frozen forms a nearly impenetrable barrier to all but the most determined bears. You may also have noticed the beavers swimming with freshly cut branches – these are carefully stuck in mud at the bottom of the pond, forming a food cache that will sustain the beaver family when they are unable to go ashore to cut new saplings.
All summer long we watched our local groundhogs gorging on green grass, flowers and garden vegetables if they could penetrate a gardener’s defenses. As the weeks went by, you could almost see the creatures gaining bulk as they fattened up. The young of the year also grew considerably, at least those who survived raids by foxes, coyotes and large raptors. But October marks the end of the feeding season as the groundhogs retreat to their deep winter dens, often constructed in a wooded or rocky area to foil predators that might try to dig their way into the burrow. Groundhogs are true hibernators that spend up to six months underground in a deep sleep, conserving energy as their pulse rate drops from 100 to four beats per minute and their body temperature falls into the 40’s.
Black bears have spent the summer and early autumn packing on the pounds and a healthy layer of fat. Gorging on vegetation, fruit, nuts and meat when it is available, a healthy bear may gain 35 percent or more body weight before cold weather arrives. They also spend several months in a winter den, but they are not considered true hibernators. While their metabolism slows and they consume no food during their confinement, their body temperature only falls by 10-15 degrees. They are actually in an intermediate state between sleep and wakefulness called torpor, since they may rouse occasionally if they are disturbed or have cubs in the den. If you happen to come upon a bear den in winter when snowshoeing or Nordic skiing, it is advisable to stay a considerable distance away from the den.
This is the time of year when the squirrels test my patience digging holes in the yard. Our oak trees are still dropping a considerable volume of acorns, a high nutrient food for rodents, white-tailed deer and turkeys alike. Rather than consume all of the nuts they find, squirrels are careful to save some of the mast for an icy day to come. Some of the nuts are stored aloft in hollow trees or cavities, some are stashed in handy spots like stone walls or garden sheds. Others are buried in a seemingly random pattern around the yard, although the squirrels have a wonderful memory for their hiding spots. Some of those buried nuts will remain underground next year and may sprout to become the next generation of oak trees. Since squirrels have insufficient body mass to sleep the winter months away, they must remain active at least in the coldest weather to eat some of their cache and keep their bodies from freezing.
Our feathered friends are also working overtime now to bulk up on calories. Those species that migrate face long flights to distant locations so they need to be in top physical condition to remain healthy when they arrive at their destinations. Many of those birds fly long distances at night, thereby reducing the chances of being picked off by an airborne predator. Sitting in the woods the other day I was surrounded by a cacophony of bird sounds as yellow-rumped warblers, tufted titmice and robins hustled about finding food. Juvenile birds can be rather naive to the dangers around them so if they are too focused on feeding, they become prey for larger creatures. Birds that remain here during the winter also need to bulk up now since food will become scarce as the months unfold.
If you have bird feeders out now, watch carefully to see how various species handle your bounty. Some larger birds like northern cardinals and finches will happily sit at your feeder for long periods while they munch away on black sunflower seeds or the like. Smaller birds like the black-capped chickadees or white-breasted nuthatches will make repeated trips to the feeder, grabbing food and then zipping off to nearby trees or shrubs. In some cases, they are using security cover to crack open the seeds for immediate consumption, hoping to avoid sharp-shinned hawks and other predators. But a variety of birds are clever enough to hide food in niches all over the area, tucking their precious seeds away in nooks and crannies in hopes that it will still be there in hard times. Scientists have determined that birds like the chickadees are capable of adding brain cells during this timeframe, giving them the ability to remember the exact location of several thousand hidden seeds. They just have to hope that some sharp-eyed blue jay does not observe their hiding places and swoop in to steal the food.
Just as humans are gathering the final crop yield from their fields and gardens, wild creatures are active for many hours each day now as the imperative of survival drives their actions. Some will perish due to inexperience or bad fortune, but those with good instincts, proper lessons from their parents and good luck will make it through the winter to once again begin the next breeding cycle. It is always instructive to observe how the circle of life unfolds around us.
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