First published in 1997 by the Ottawa Field Naturalist’s Club in the “Trail and Landscape” 31(4):146-147 , erectile
this article by long-time Keyworth Avenue resident Jack Holliday celebrates and explains the relationship between the bur oak and the squirrels. Mr. Holliday published 27 articles in this journal between 1987 and 2003.
By Jack Holliday
The riverside park area of Ottawa (between Island Park Drive and Tunney’s Pasture) is blessed with some magnificent Bur Oaks. These trees, most over 100 years old, produce a bountiful crop of acorns each year. The acorns are food for crows, Blue Jays, grackles, and squirrels. Oh the squirrels! Black or grey, they thrive on the acorns, supplemented in season, by apples, berries, tulip bulbs, food scraps, and in winter by the generous humans who keep bird feeders filled for the squirrels to raid.
The acorns are the staple, on which every squirrel depends. September is the month that the acorns ripen, but long before that month the squirrels are busy eating the not-yet-ripe seed.
When the nuts ripen and drop to the ground, squirrels hasten to carry each and every one to an area where a hole can be hastily scratched, the nut firmly forced into the hold and covered, before the squirrel races to get the next one. Such activity. Favourite “spots” for the hiding of the nuts are places with soft earth such as found in gardens. Not surprising then is the unearthing of dozens of acorns by gardeners. Spring, summer, and fall, whenever we dig in our gardens, we unearth acorns.
Over the years my casual look at the “up-dug” acorns revealed a surprising number that had been damaged by a hold excavated in the top or the bottom of the nut. “Some insect,” I surmised, before tossing it aside (to be gleefully claimed by the next squirrel passing that way).
However, this year, I truly looked at some of these unearth acorns. Not insects. No, these holes had been made by squirrels. The marks of the teeth were quite evident. That being so, the question arose as to why the squirrels would damage the nuts in this manner?
To me, the answer seems to be that the acorn is damaged in such a way that will prevent the acorn from growing. Either the bottom of the nut where the tap root will emerge, or the top where the cotyledons will developed, is chewed away so that acorn cannot develop normally.
In May, with moist, warming earth, the hundreds of thousands of buried nuts will stir into life, and soon the emerging cotyledons will be evident everywhere. Not so with the “doctored” nuts. Unable to grow, they will remain in the earth protected from rot by the high concentration of tannic acid of which oaks are famous. They will certainly last through the summer, perhaps longer, fresh and plump as the day they were buried, to provide “out-of-season” food for the provident squirrels.