The large black oak stands alone in the field. It is a survivor. The tree was spared when the rest of the forest was cut to create a pasture. Unlike their white oak relatives, black oaks usually grow in the shade of a Douglas fir forest. Only when well-established can they tolerate an unfiltered Southern Oregon summer.
It's October, and on a warm, sunny day there is nothing more important for me to do than lie under the tree and stare idly up through the branches. The leaves are turning a bright yellow, but there are other colors as well, including several shades of blue and a touch of red. The red belongs to the acorn woodpecker, and the various shades of blue belong to western scrub jays and Steller's jays.
It is harvest time, and the crew is hard at work. A family of acorn woodpeckers carts off acorns in relays and sequesters them in their granary. The granary consists of thousands of small holes usually drilled in the soft wood of a dead ponderosa pine. Each hole is the perfect size to receive and safely hold an acorn for a meal sometime in the year to come.
The jays also have thoughts of future meals, but their strategy is different. Trip after trip in the clear fall skies, they pluck acorns and sail off to tuck them away for the lean times. Steller's jays head back into the forest, where they bury them or place them in some recess. They are so secretive that I have yet to see one hide its prize.
Scrub jays head in the opposite direction. They head for more open areas. Most often they bury acorns in the ground. One time I watched a jay carefully press one into a lawn. It took several attempts before the jay was able to bury the acorn sufficiently to meet its approval. Then it picked up a fallen leaf and placed it very carefully over the top of the buried acorn. Did the jay really expect the leaf to remain in place and mark the spot until it was ready to return, possibly months later? It's optimism such as this that explains the abundance of black oak seedlings on my property. The nearest mature black oak is some distance away in a neighbor's yard.
The hope is not totally unjustified. Members of the crow and jay family have excellent memories. The champion is the Clark's nutcracker, which lives high in the mountains in places like Crater Lake where snows hide most potential food for much of the year. Studies have demonstrated they can remember where they have cached more than 10,000 seeds for a period of up to nearly a year. Scrub jays live in the lowlands, where there are many more feeding opportunities, and their memories are no match for the nutcracker. It is not as critical that they remember where every stash is. Steller's jays have somewhat better memories than scrub jays, but nowhere as good as the nutcracker.
For now I am savoring one last warm day, content to watch others hard at work. Soon it will be time to retreat to the warmth of the house and my own food cache in the refrigerator.
Stewart Janes is a biology professor at Southern Oregon University. He can be reached at firstname.lastname@example.org.