Starting on the first of September, I keep a watchful eye on the swollen fruits hanging from the two prized pawpaw trees growing in my backyard forest. The largest and most delicious fruit native to North America is almost ripe, and this year, I should harvest a pawpaw crop exceeding 20 fruits. Out back the other day I started daydreaming of prehistoric giant ground sloths—the original dispersers of pawpaw—roaming along the Potomac River, sniffing the aromatic ripe fruits and bending the slender trees down to grab their custard-like dessert.
My daydream was swiftly interrupted by a small swarm of aggressive mosquitoes that forced me to beat a retreat. What is going on in our backyards? It’s September and the mosquitoes are still thick. It’s enough to consider not only applying mosquito repellent but also resorting to broadcast spraying to kill the pests.
Please don’t. Someday soon, we will be able to release sterile male mosquitoes in our yards or across entire neighborhoods or apply other natural controls to take back our backyards. Or, if you are growing vegetables and tempted to spray for garden pests, or striving for a perfect grass lawn, please, homeowner, put away the Round-Up. There are natural concoctions that work just as well without the indiscriminate killing that is contributing to Insect Armageddon. (See my article in last month’s Village News.) Besides, persistent indiscriminate spraying also increases the likely evolution of resilience of the heirs of the survivors, making the pesticide less effective should there come a time it is really needed.
Pesticides never target one species, like mosquitoes, but kill almost every bug with which they come in contact, while also spreading the risk of environmentally caused cancers in humans. By trying to control insects with chemical poisons, we are inadvertently compromising the integrity of our local ecosystems. Herbicides add to the problem by sinking into the soil and killing off soil invertebrates that play a critical role in the ecology of soils.
But let’s stay above ground and consider the consequences of widespread use of pesticides and herbicides to our most treasured aerial neighbors — the birds that roost in our backyard trees and shrubs and fill our lives with nature’s songs. If you only remember one sentence from this article please hold on to this thought:
The birds we love are made from bugs.
OK, American Robins hunt worms but even earthworms disappear after heavy applications of herbicides and the robins may then starve. And just before fall migration, many resident birds switch to eating fruits before departing for warmer climes. But when they head north again, nest, and raise their young, it is the flush of caterpillars and bugs that sustain them. And in turn, they act as our natural pest control agents if we only give them a chance.
Evidence of their ecological roles echoes and shapes their common names. The start of Spring to me begins with the “wheep” call of the Great-crested Flycatcher singing from high in the treetops in my backyard forest. Flitting up and down the tree trunks and branches are lively Blue-gray Gnatcatchers, flicking their tails as they merrily gobble insects. And it’s not just our Great-crested or the deep-in-the-forest Acadian Flycatcher that reflect their roles in their names. There are lots of species in the tropics whose last name is “flycatcher.” Besides gnatcatchers, there are groups of birds called bee-eaters and spiderhunters. Even birds without allusion to a bug in their common names share a common food source—the millions of insects that left unchecked would defoliate our forests.
Songbirds do their work in the daytime and our insect-eating bats take the night shift. From beetles to moths to mosquitoes to flies, bats vacuum up the insects flying in the warm night air. Sadly, I now notice fewer and fewer bats flitting about over the 25 years I have lived in Cabin John. My evidence is only anecdotal, but I suspect bats are in decline here just as they are in areas where they have been monitored.
I’ve gone out back daily to check on the pawpaws. Although delicious, the fruiting season is exceedingly short—a matter of days. If you don’t pick the yellow-green fruits just as they begin to turn soft, deer, raccoons, opossums, or squirrels will devour them. The mosquito swarm returns, shortening my inspection. But as I return to the porch I hear the sound of a Carolina Wren calling from a low branch, though with an imperfect “Tea-kettle, tea-kettle, tea-kettle”—it must be a young bird hatched early in spring or perhaps a fledgling from a second clutch, made possible by the abundance of insects in the yard.
Ecology is about balance. I love the sounds of warblers, flycatchers, woodpeckers, gnatcatchers, wrens, and catbirds. Let’s let them live their lives—goodness knows they are short enough—without poisoning them and ourselves with pesticides.
By Eric Dinerstein
Illustration by Trudy Nicholson