Berry Season

By Curtiss Clark

The shy catbird gave up the comforts of his birch-leaf lair for some uncharacteristic exposure atop a sun-baked stone wall — a perch that afforded him a better view of the low-bush blueberries Kate and I planted in a new dooryard garden this year. (Bird thought: So many berries, and so few opportunities for pillage unhindered by the proprietary dog, or the man waving arms.) The catbird gave its mewling squawk of approval and launched his raid. I ran out from the kitchen, waving my arms.

It’s berry season, and there is plenty of contention over the spoils of fruiting plants. It’s war, and as always, the victors in this particular war are the plants.

The fruit lovers in the animal kingdom, ranging the least wisp of a wren to the earth-thudding elephant have been led by the palate down the evolutionary path by plants with a critical interest in seed dispersal. Every fruit is a conveyance system wherein a seed rides in its own lunch bucket of nutrients and sweet calories. It is more than happy to share the bounty with those birds and beasts willing to give it a ride to some far-flung ground where it won’t compete for sun and sustenance with its immediate ancestors. Often the seed is planted at its destination with a generous dose of contributed fertilizer.

In her wonderful book, The Ghosts of Evolution, science writer Connie Barlow traces the parallel evolutionary paths of plants and animals to show how plants reached across the flora/fauna divide to hitch rides with animals. Some did it by developing Velcro-like burrs and attaching themselves to passing animals, and others did it by making the embryos for their seeds delicious. Both plants and animals adapted to each other with varying degrees of success. Birds routinely gorge themselves on pokeberries that would poison us.

Some fruiting plants are anachronisms, according to Barlow. There are still some large tropical fruit pods in Costa Rica waiting at the base of Cassia grandis trees for mastodons that haven’t shown up for the past 11,000 years. No other animals have developed the size or masticating prowess to eat them. So the pods lie where they fall, limiting the range of the trees.

Even though Kate and I are eating pecked-at leftovers from the raspberry patch, and ours will be a pauper’s portion after the catbird’s blueberry feast, we don’t feel too bad about our capitulation to the birds in berry season. They are fulfilling the plants’ evolutionary imperative far more efficiently than we ever could by eating berries on our cereal at the kitchen table.

(This and more than 65 other Field Notes essays are available at www.fieldnotebook.)