Hundreds of baby bobolinks died this week. Sadly, it was unavoidable. Mostly.
One reason so many people love to watch birds rather than, say, toads, is that birds are so adaptable and widespread. Birds have filled virtually every possible niche on earth, from snowy owls on the Arctic tundra to penguins on the Antarctic ice sheet, from roadrunners in the desert to rails in the marshes. Every species is adapted to a particular habitat.
Unfortunately, hay fields are among those habitats. Maine grasslands are home to bobolinks, eastern meadowlarks and savannah sparrows. But meadowlarks are nearly gone altogether, and bobolinks are disappearing rapidly. Bobolinks have declined 65 percent since I was a kid. It’s the unlucky consequence of conflicting needs.
Hay is a commercial crop, no different than corn or potatoes. Farmers need to harvest multiple times a year just to make ends meet. But it’s the Grim Reaper for grassland birds when that first harvest occurs too early, when nestlings and fledglings cannot escape the approaching blades. Chicks remain flightless for days after they leave the nest, as their wings continue to develop and strengthen. They are stuck in the grass when danger comes. In one busy morning, an entire breeding season of grassland birds can be wiped out.
Don’t blame the farmer. Farms are the whole reason bobolinks got established here in the first place. Originally, bobolinks were confined to the tallgrass prairies of the Midwest and Canadian provinces. Agriculture cleared the eastern forests and opened up nesting habitat throughout New England. But that was back when horse-drawn harvests started in mid-July.
Bobolinks already face huge challenges. They have one of the longest songbird migration routes in the world, taking them from northern grasslands all the way south to the pampas of Argentina, where they spend the winter. They completely change their feathers twice a year, not only because of the long flight, but also because of the wear and tear that comes from constantly bumping up against the sharp blades of grass where they make their homes. And once they are done nesting, they often have to shift their homes in Maine to wetlands and coastal dunes, searching for enough food to fuel the long flight ahead.
A bobolink’s life is … complicated. They are polygynous, which means that each male mates with multiple females. But they are also polyandrous, which means that each female is sitting on a clutch of eggs that may have been fertilized by multiple fathers. Males spend a lot of time vigorously defending their territories, but apparently anything goes once they’re hidden among the stems. What happens in the grass, stays in the grass.
The plight of the bobolink has been a concern for a long time. Several projects have been launched to look for solutions. One federally funded project pays farmers to delay haying. This has worked reasonably well, but there are constraints. The grant money is limited, and in many cases farmers need that early hay. It is the most nutritious crop of the year. Horses, sheep and beef cows are better able to digest the coarser hay that results from later harvesting, but dairy cows are less so.
A bold experiment in Vermont involved super-early mowing, around the beginning of June. Most birds had returned from South America and were in the midst of courting, but only a few had managed to actually nest that early. Those nests were lost, but soon the grass was tall enough that re-nesting was possible, and late-pairing bobolinks found enough cover to get started.
In Maine, our best strategy may be to mow fields that produce hay for dairy cattle, and accept that some grassland bird chicks will die. But we could delay haying fields that aren’t used primarily for commercial crops. Some of our best remaining grasslands are on state and municipally owned property. Private homeowners and trusts also hold grassland properties. On those parcels, mowing might wait until mid-July, or preferably the beginning of August.
Some parcels are mowed only to keep the fields intact, since the forest will regenerate if allowed to. These fields can be mowed in the fall to prevent the growth of shrubs and brambles. In fact, a mowing once every three years is sufficient. If shrubs do begin to emerge, they actually make good perching spots for bobolinks, and may encourage American woodcocks.
Don’t think of it as delayed haying. Think of it as raising a crop of bobolinks.
Bob Duchesne serves as vice president of Maine Audubon’s Penobscot Valley Chapter. He developed the Maine Birding Trail, with information at mainebirdingtrail.com. He can be reached at duchesne@midmaine.com.
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