Sue Pike| Portsmouth Herald
A friend recently told me about the inordinate amount of squirrel activity around his house, much of it targeted at collecting pine cones and carrying them off to secret locations.
Squirrels, red squirrels in particular, love pine seeds. It takes a lot of effort for a squirrel to strip a pine cone and get at those two tiny seeds located at the base of each scale, but they are worth it because pine seeds are loaded with fat.
More than 50 percent of the weight of a pine seed is fat, something that all overwintering animals need to survive; this is why seeds and nuts are so popular at bird feeders. Seeds and nuts contain the energy needed for that young tree to germinate and grow until it can start producing its own food via photosynthesis. That energy equals calories. Fats and oils are compact, high-quality sources of calories, perfect for packing into a tiny seed, perfect for helping a small, fuzzy mammal stay warm on a cold winter's night.
Squirrels do one of two things with a pine cone: eat the seeds immediately or cache them. Pine seeds that will be stored (cached) for later use need to be handled with care. Exposure to oxygen can be detrimental to the pine seed, affecting its germination rate. Pine trees have a number of adaptations that help protect their seeds from the ravages of oxygen.
The coating on a typical pine seed is often loaded with antioxidants. In addition, some pines have tightly sealed cones that greatly reduce exposure to air. Pine nuts found in these tightly sealed cones can remain viable and able to germinate for decades.
Kim Long in her fantastic book "Squirrels: A Wildlife Handbook" notes that because of their higher nutritive value, squirrels prefer seeds from sealed cones (before they have opened up in preparation for fertilization). Red squirrels will cache whole pine cones deep in middens (piles of organic debris, often piles of old stripped cones) where it is dark and cool and wet; a low-oxygen environment that keeps the seeds fresh and keeps them from germinating. The cache of one red squirrel can contain up to 14,000 pine cones.
This method of caching large stores of food in one place is known as larder-hoarding. These pine cone middens were well known to foresters in previous centuries who would raid the middens for seeds to plant as nursery trees and for reforesting woodlots.
Foresters aren't the only ones to raid squirrel middens. The big challenge of hoarding food is protecting it from thieves. Gray squirrel thievery of seeds and nuts from red squirrel middens can be significant enough to impact the health of the victim. Unlike red squirrels, gray squirrels scatter-hoard, distributing smaller amounts of food throughout their territory so that if one hoard is discovered, they will not lose all of their stored food, thus minimizing the impact of pilferage.
My friend who observed all of that squirrel activity was mostly watching gray squirrels and discovering their caches, in his tool shed, under tarps, in piles of lumber. He found stripped cones and tightly closed, unopened cones.
These caches could mean the difference between life and death to a squirrel in a really harsh winter, so it is best to resist the urge to clean up that cluttered corner or at least wait until spring when fresh food becomes available again.
Sue Pike of York has worked as a researcher and a teacher in biology, marine biology and environmental science for years. She teaches at York County Community College and St. Thomas Aquinas High School. She may be reached at spike3@maine.rr.com.
