Sunday, June 3, 2012

Lusty bobolinks are tuneful showoffs




The Columbus Dispatch
Sunday, June 3, 2012

NATURE
Jim McCormac


“Robert is singing with all his might: Bob-o’-link, bob-o’-link, Spink, spank, spink.”
— excerpted from Robert of Lincoln by William Cullen Bryant (1864)

Poet William Cullen Bryant wasn’t the only person to become enchanted by our most remarkable blackbird. Emily Dickinson and others have penned scores of lines gushing about the bobolink. If you see a field full of the black, white and gold birds in display mode, you, too, will fall under their spell.

A bobolink weighs the same as nine nickels, but its intrinsic value is priceless. A male in breeding finery is a stunner. Its sharp white upperparts provide contrast to a belly of the deepest ebony. Rich molten gold paints its nape, capping the bobolink’s costume. The male bobolink seems to have donned a tuxedo backward. Females are plainer, resembling large sparrows airbrushed with a mist of ochre.

Like clockwork, early May sees the return of male bobolinks. With great pomp and circumstance, they drop into Ohio’s meadows and set about transforming quiet leas into raucous festivals. Males carve out territories, and bobolink fields are alive with the aerial displays of the avian extroverts. Wings stiffly aquiver, the males sky-dance in circles over favored turf, sending down a glorious cascade of bubbling gurgles punctuated with singsong bell notes.

The females slip in about a week after the males. Suddenly, it is as if they’ve entered a fern bar full of testosterone-filled feathered lounge lizards. It isn’t uncommon to see three or four males hot on the heels of a female as she wings over the meadows, the boys furiously vying for her attention. Male bobolinks mate with more than one female — some assemble a harem of up to five females — and the females, in turn, often mate with more than one male.

By late August, the bobolink fields have fallen quiet, and the birds collect in loose flocks. If all went well, they will have successfully fledged many new bobolinks from ground nests hidden in the grasses. Tragically, bobolinks often favor hayfields, and harvests frequently coincide with the peak of nesting. Many a crop of bobolinks is annihilated in favor of farm-animal fodder.

Few of our breeding birds can match the epic migrations of the bobolink. Their winter haunts are in South America, where they occupy a narrow corridor in Argentina, Bolivia western Brazil and Paraguay. A one-way trip to central Ohio might be 6,000 miles — a 12,000-mile annual journey. A bobolink that reaches the age of 9, as they can, will have flown the equivalent of almost 41/2 times around the Earth.

Many songbirds use celestial objects to orient themselves during migration. But bobolinks often migrate during the day, when stars aren’t visible. Research has shown that they have iron oxide embedded in certain tissues, which syncs them to the Earth’s magnetic field. Thus, magnetic cues allow the birds to unerringly navigate extreme distances to the same small meadow time and again.

An Eden for bobolinks is the sprawling grasslands of the Wilds, a 10,000-acre conservation and research reserve in Muskingum County for imperiled large animals. Scores of bobolinks breed at the Wilds, and it is surreal to see them in pastures with giraffes, rhinos and scimitar-horned oryx.

 Naturalist Jim McCormac writes a column for The Dispatch on the first and third Sundays of the month. He also writes about nature at www.jimmccormac.blogspot.com.

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2 comments:

Mary Ann said...

My family has farms in Wisconsin; they always wait to harvest hay until after fledge time; as they spread the word as to why, gradually nearly all the farmers in the area followed suit. It doesn't typically make that big of a difference to them; it's only waiting a few weeks longer than usual. There is plenty of other work to do in Spring when you're a farmer!

Jim McCormac said...

Excellent work on your family's part, Mary Ann! I'm glad their example is spreading. If only all farms would do the same, we'd have far more Bobolinks!