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Concentration of CO2 in the Atmosphere

The Ultimate Migrant Farmworkers

Birds Outperform Pesticides

A kestrel finds a rodent to feed on. (

Jessie Haas

If you’ve ever grown fruit or berries, you know the ambivialence farmers feel about birds. A beautiful and essential part of nature, they can also be a pest that eats into crops and profits, damaging from $104 worth of Oregon tart cherries per hectare and up to $7,267 worth of Washington Honey Crisp apples in 2013.

But birds can be part of the solution, too, as some farmers have known for decades. Forty years ago, the son of one Cherry Bay Orchards worker, to complete an Eagle Scout project, built and installed kestrel nest boxes on the Orchards‘ property. They were immediately occupied by kestrels and continue to have a 75-80% occupancy rate. The kestrels do an excellent job of reducing bird and rodent pests, which are particularly damaging to seedling trees. Another cherry grower, Jim Nugent, installed kestral thirty years ago. “From the time I started getting nesting kestrels, I sure observed a decline in problems,” he says.

Kestrel nest boxes have several advantages over other means of pest control. The birds are feeding young families, so they are self-starters and highly motivated. They kill and eat some pests and scare others away; the scare effect does not wear off, as it does with propane cannons, balloons, and hawk silhouettes. And they are popular with the public and extremely cost-effective. Every dollar spent on a nest box saves between $84 and $375 worth of fruit and avoided costs. Nest boxes on farms are good for the kestrels, too. Their numbers are increasing in cherry-growing counties that use them, while kestrels have declined fifty percent continent-wide in the last fifty years.

One size does not fit all when using wild birds for pest control, however. Farther south, starlings tend to take over the nest boxes Kestrel chicks fledge and leave the nest before blueberries ripen, so there is no protective effect for blueberry growers.

But other birds can also be helpful. Lured by nest boxes, barn owls have been partnering with farmers all over the world to kill rats and other harmful rodents, including in wine country in Israel and California . Nest camera studies show that a single owl family will eat around three thousand gophers, mice, and voles. Barn owls prefer nesting and hunting in natural areas over farmland, but in nest boxes on the wilder margins of farms, GPS tracking shows that they spend one third of their time hunting cultivated land.

All of which pushes the conclusion that science has been showing for several years now. It is beneficial to wildlife and to farms to keep some areas uncultivated. A little brush and woodland along the edge of the field, combined with a cultivator strip of native flowering plants and a beetle bank of tall, uncut grasses, creates a home for beneficial insects and for birds, hunting ground for owls, cover for insect predators, and resting places for migratory birds and butterflies.

Songbirds can also play a crucial role in reducing the numbers of insect pests. ‘Our’ warblers, the ones that summer in the Northeast, like black-throated blue warblers and American redstarts, winter in Central America, where they consume coffee berry borer in shade-grown coffee plantations, benefiting growers to the tune of $126 per acre in saved crops and avoided pesticide costs. The right cup of joe in the winter can help provide habitat for our birds, so they can return in the summer to delight us.

Bluebirds are easily attracted by nesting boxes. Providing boxes can quadruple the number of nesting birds in an area, and bluebirds eat two to four times as many bugs on farms with manmade nest boxes as they do on farms without them.

The message from nature is the same no matte where you look. Biodiversity isn’t some nice-to-have frill. It’s how the whole thing works. Not surprisingly, farmers who understand that and find a way to work with nature reap benefits in profit and reduced work.

Jessie Haas has lived for 36 years in an off-grid cabin in Westminster West, VT. She is the author of 40 books for children and adults, most recently The Hungry Place.


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