Stuck at my desk, clearing the last to-dos so I can head to the cabin, I’m feeling the crushing weight of another Anchor deadline. The songbirds and gray squirrel feeding a few feet away are a diversion. The germ of an idea is in my head but undefined when BANG — something smashes into the sliding glass door! I look up in time to see the back end of a sharp-shinned hawk streaking from the scene and his feathers littering the ground.
Any writer will tell you that story ideas often pop up when you least expect them, and I had to run with this one. While I am keenly interested in all the raptors, it was the interaction between hawk and squirrel that sealed it. Full disclosure: I am irritated with the squirrels this month because they are tearing holes all over the yard. With acorns raining down, the squirrels are working overtime to bury their harvest before other creatures gulp down the bounty.
We are in mast season, the time of year when the fruits of many trees and shrubs are falling. Hard mast includes dry fruit from oaks, beeches, black walnuts, conifers and hickory trees. Soft mast includes raspberries, cherries, apples and blueberries. During this season, there is a rush for all kinds of wildlife to snatch as much food as possible to pack on the pounds and fat layers for the coming winter.
In Europe, an ancient practice known as “pannage” involved farmers turning their hogs loose in the forest to gorge on acorns and chestnuts. (Sadly, there are few chestnuts around here these days). This continues today in England’s New Forest, fattening the hogs while removing excess acorns that can be toxic if consumed in large quantities by cattle or wild ponies.
Scientists have found that mast forms the foundation of autumn and winter diets for most wildlife dwelling in forested areas. Nuts and fruit are high in carbohydrates, fat and protein, along with potassium, calcium and phosphorus. A black bear gorging on such foods might gain 50-100 pounds before retiring to a winter den. White-tailed deer and wild turkeys will forage for many hours during this period, using their feet to scrape away leaves on the forest floor in search of nuts. Woodpeckers, blue jays, mallards and wood ducks also feast on these delicacies.
Of particular interest to scientists is the intermittent frequency of masting, which occurs in variable cycles over periods of up to a dozen years in some forests. Some years it is hard to find a quantity of acorns. In other years, they are raining down in vast numbers, nearly covering the ground under mature trees with large canopies. This has significant consequences for wildlife species dependent on mast for growth and survival, especially juveniles. Studies have shown that mast seeding has become more variable during the last century, probably one more result of climate change.
Scientists also are studying another phenomenon of masting, that of synchronous production among many plants in the forest. While the forces that trigger these cycles are not fully understood, it is thought that there are benefits for forest diversity and regeneration, rare plant conservation, disease suppression, and resistance to invasive species. When masting is heavy, more squirrels, mice and birds will be strong enough to survive their first winter. In years when mast is scarce, most juveniles will not live to see the next spring. It is no surprise that this affects both prey and predator species, with regular peaks and valleys in their populations.
That gray squirrel and his buddies are not tearing up my lawn just to be devious, although there is room for discussion here! When food is available in excess, squirrels can afford to set aside supplies for a cold winter day or a late spring. While they might gorge on soft mast as soon as food is available, squirrels are more likely to hoard nuts, in some cases storing thousands of them in trees or caches below ground. One theory, the predator satiation hypothesis, says that mast-bearing trees have evolved to overproduce every few years so more buried nuts survive to take root and ensure the regeneration of the forest.
Mast abundance this year ensures that my gray squirrel will remain in a mad rush to “squirrel” away as much food as possible. Head down, digging another hole in my yard, he just might fall prey to that lurking sharp-shinned hawk!
