Sitting alone along the edge of a field underneath a dense cover of leafless hardwood branches I watch for wildlife through my binoculars. Like most days spent in the field more happens in my mind than in the wild landscape before me. Still, I am hopeful for some wildlife activity that will peak my curiosity. Waiting in the wilds is a lonely game. I watch the shadows as they lengthen in the aging day. I watch a few clouds, and wish they would shape into wild images like those you read about in stories. I look at my watch again and again, and wonder how time could move so slowly, and then I look at my watch with a suspicious eye and realize that it isn’t working!
It is one of those days when nothing seems to be moving; there is no wind to move the branches above my head and no birds to flitter about the shrubs in front of me. I am not surprised, most of the time wildlife observing has nothing to do with observing wildlife, but rather observing where your mind travels with only its own impetus. On this day I am wondering how our world recovered so quickly after being entirely decimated by the last glacier period. Twenty thousand years ago or so the advancing glaciers, ice sheets miles thick, absolutely wrecked this part of the planet. All animals, plants, soil land formations, and features were displaced completely by the mountains of advancing ice that dominated the landscape. The more fortunate animals were able to migrate away from the advancing ice sheet, but the animals that were not mobile, or incapable of moving ahead of the glaciers were decimated. All plant communities, being primarily immobile, were decimated. Land forms left by previous glaciers were annihilated. Lakes, ponds, and many river beds were filled, scoured, removed, or otherwise wiped out beyond recognition. There were no survivors. Nothing could withstand the type of slow, methodical punishment that the glaciers handed out.
Eventually, thousands of years later, the glaciers retreated slowly. The world they left behind was a moonscape; miles and miles of bedrock and naked earth with no signs of life anywhere. Barren does not even begin to describe the landscape left behind the retreating glaciers.
While I am lost in these thoughts a blue jay lands about 100 feet in front of me. He is holding an acorn in his beak and scratches in the soil puts the acorn down and scratches soil over this oak fruit and flies away. About ten minutes later he returns and does the same thing all aver again. He does this over and over again. Given the time he is gone I understand that the Jay must be transporting the acorns some distance, likely to a spot near his nest. Blue Jays have had a symbiotic relationship with the oak family for thousands of years. The blue jay uses the acorn as a main food source. In turn he plants the acorns up to a mile away from the parent tree usually near its nest, spreading the genetics of that particular tree and expanding the oak forest. A blue jay may move 3000 to 5000 acorns in a given year, only about one fifth to one third of those acorns will be recovered as food. Some of the remaining acorns will be foraged by turkeys, deer, squirrels, chipmunks, and other wild animals, but many will sprout and with a great deal of time grow into oak trees. Not all jays take part in this behavior, some of them migrate south for an easier winter life style.
Immediately after that thought the proverbial light bulb went off in my mind! Eureka, another piece of the puzzle! Is it possible blue jays had a hand in the recovery of the oak forest after being decimated by the glaciers?
Beyond the terminal moraines of where the glaciers stopped there remained unharmed plant communities, wild animals, some of which migrated ahead of the advancing glaciers, and untouched landforms. Some of the higher elevations held some of the same plant species that inhabit more northern latitudes, just like they do today. For instance although the Appalachian Mountains in North Carolina are 800 miles south of the Green Mountains in Vermont they hold some of the same plant communities. The tall Appalachians make up in altitude what they lack in latitude and may have a similar climate to the foothill regions of the north. Although some of the plants may differ, particularly the ground cover plants, many plants may be the same in these two regions due to the altitude difference.
It could be that some of those Jays trying to stay ahead of the glaciers as they advanced in a southward direction settled in high southern altitude areas that still contained some oaks. As the glaciers retreated the resurging plant communities slowly followed the path of the retreating glaciers. First the wind born seeds of herbaceous plants and grasses, then the shrub community, some of which can be spread by root rhizomes, and others by which can be spread far and wide by animal foraging. The trees go last. First the trees that have light seeds, like maples and ash, can repropagate by stout winds dispersing the seeds far and wide. Others, like the black cherry utilize a small hard seed consumed by mammals and birds, and redistributed in scat. But the trees with heavy seeds like the oak seemingly have a problem. Squirrels and chipmunks typically only move them a few hundred feet at a time. Mammals that consume the acorns digest too muck of the seed for it to remain viable.
Could it be that Blue Jay, the pesky little boss of the forest, may have contributed heavily to the replacement of the oak in the northern deciduous forest? Although unintended, the blue jay may be responsible for the fast return of the oak to northern climates and the salvation of many of the forest inhabitants. This bird has special adaptations like a beak that can crush the tough and resilient acorn husk and a throat that expands so that it can carry an acorn while the Jay is in flight. The oak is, along with the beech nut, the premier hard mast (nuts, seeds,and acorns) forage crop of the modern deciduous forest. Before the American chestnut suddenly perished in the early part of the 20th century it was the king of hard mast.
Millions of pounds of forage were produced annually. Its sudden failure created a large gap with respect to wildlife forage. Primarily the oak and it’s seed, the acorn, had to fill this gap.
A strong cool wind from the northwest shakes my thoughts loose and returns me to my surroundings. The day is now long in the tooth and the shadows have lengthened into dusk. As I stand up and turn myself westward I can see the remaining light of day melting away on the horizon. And just then,as if prompted by the bird gods, a blue jay cries from the branches above, and my day is complete with new possibilities and new revelations.
Originally written in September of 2007