Birds of a Very Different Feather
by Tom Dunlop
In March 1932, the last heath hen in the world was seen for the last time on Martha's Vineyard.
The race of birds was declared extinct, despite the energetic – but fatally tardy – efforts of man to undo on the Vineyard what he had so callously done to the bird on the mainland. Now a genetic study has determined just how unique the Vineyard heath hen really was. And the results may bear heavily on the question of whether a related species in the Midwest might one day be brought to the Island to take the heath hen's place.
The room in the Environmental Sciences Center at Yale University is long and white and cold, and the sarcophagus for the dead birds lies at the far end behind a thick, padded door that clicks heavily when you open or close it. Eric Palkovacs lifts the birds out, species by species, cradling them in cupped hands the way you would a newborn in the delivery room. He lays the shells of the birds side by side on a tray, a murdered row of extinct (or almost certainly extinct) fowl. The ivory-billed woodpecker, its color as black as Dracula's cape, a streak of red behind the eye. The bright green little Carolina parakeet. The passenger pigeon.
And then there is the heath hen, still plump in its vestigial form, but with small dots of cotton where the eyes once were – and peeled from the pad of a toe, a sliver of skin not much more substantial than an eyelash. From this scraping has recently come a genetic autograph of the bird, and perhaps a prophecy about whether the nearest surviving relative of the heath hen can – or, perhaps more importantly, should – be brought to Martha's Vineyard, the place from which it vanished from the globe seventy-two springtimes ago.
The last heath hen in the world was seen for the last time on the Island on the morning of March 11, 1932. It pecked its way carefully onto the lonely old mating ground of Jimmy Green's farm just off the Edgartown–West Tisbury Road in West Tisbury. The next day it didn't come. Nor the next, nor the next. A year later, after it failed to come at all, they declared it officially extinct. The last bird was dead, the race was lost, and whatever hope there might have been, long before, for the survival of the subspecies was now entirely spent. This, despite the energetic but terribly late efforts of man to try to undo on the Vineyard what he had so fatally done everywhere else on the mainland.
The heath hen was famous because of the way it courted other heath hens. Like the greater western prairie chicken and other relatives still hanging on to life despite the loss of habitat in the Midwest and beyond, the heath hen (Tympanuchus cupido cupido) gathered in the early morning hours on ancestral trysting grounds and put on a show. It stamped and charged and jumped and turned half-circles in the air and bowed and threw forward its pinnae feathers along the neck as if they were horns. It puffed itself up, cackled and whirred, and then it made a noise.
It sounded, wrote Edward Howe Forbush, the state ornithologist of Massachusetts, like the "subdued and distant echo of many medium-pitched steam whistles." Produced by the inflation of two orange sacks arranged on either side of its throat, the booming of an amorous heath hen could be heard a mile or more away on still spring mornings – "a vital, virile expression of the Fecundity of old Mother Earth . . . a rune of reproduction," wrote an ornithologist who came to the Vineyard to see and hear it in 1916.
And by 1916 the Vineyard was the only place he could see or hear it. At one time the heath hen had been found up and down the entire eastern seaboard, from Maine south to North Carolina. It thrived in an agricultural economy; farm and field offered it food, booming grounds, and open land on which to nest. So common was the heath hen in the earliest days of the country that the bird wandered around Boston Common. In colonial times, when servants couldn't bargain for much, they sometimes won a concession from employers that heath hen not be served to them as dinner more than two or three times a week.
That was then. By 1870, they were gone from everywhere on the mainland. Hunters downed them easily. The land grew over as people moved from farm to factory and town. They were trapped and sold for pennies as a rather strong-tasting game bird in the big city markets. It was Darwinism on a typically blunt and indifferent human scale, except on the Vineyard, where the bird managed to hang on an epochal instant longer.
Here, in the very center of the Island, there lay an open, arid landscape of tangled huckleberry, bushy rockrose, occasional patches of grass, but mostly scrub oak – "a barren ragged plain of no town," wrote Simon Athearn, late in the seventeenth century. No one plowed the sandy, acidic soil, because crops wouldn't grow on it. Nobody built anything there. Nobody wanted it. "Wast land," the first maps called it.
"The trees are all young," wrote the geologist Nathaniel Shaler, who toured this scrubby vastness in 1874. "In most cases from the saddle or carriage seat the eye ranges above their tops for miles over a billowy sea of the deepest green . . . all of a deep, rich hue, with a wonderful gloss, surpassing in brilliancy anything we get on the main-land." This was the Great Plain, unlike practically anything we see today in the planted, alien, overcrowded stands of the State Forest that grew above it and now shade it out.
The Great Plain was breathtakingly low and broad and open because it was swept regularly by fire. Studies show that fires were set from the time
of the first inhabitants, even before the Island was surrounded by the sea. Fire cleared the wilderness for camps, for hunting, for berry-picking. Fire helped seeds to burst open and sprout and kept trees from blocking the sunlight on younger edible plants. Fire, the scientists all agree, became as vital to the ecology of the Great Plain as sun and wind and rain. It was heathland in the classic sense of the word, just the way the heath hen wanted it.
In 1908, the commonwealth acquired the first six-hundred acres of the old Great Plain in a Teddy Roosevelt–era attempt to save the habitat of the last population of heath hens on the planet. A warden was hired to kill predators, guard against poachers, and feed the birds. The numbers rocked up and down for the next twenty years. But inbreeding, disease, and infertility did their inevitable dirty work.
By 1928 there was only a single male left. He was called Booming Ben, and in his last years he became known as the most protected bird on earth. The New York Times picked up the story. So did the Associated Press. Birders came from around the world to see him. In the spring of 1933 he failed to return even once to the last booming ground just west of the original heath hen reservation. Alfred O. Gross of Bowdoin College, who had studied the decline of the bird starting in 1923, pronounced him dead that spring, and his race extinct. It was, he said, the first time in ornithological history that an extinction had been observed in the wild down to the last individual.
The state kept buying Great Plain habitat to try to save the bird after 1908, but it also planted red and white oak on the heathlands to jump-start an Island lumber industry, which did the open-land bird no favors as it winked out of existence. The lumber market never materialized, the red pine came down with a blight called diplodia pinea, and fire was suppressed because a forest could rapidly burn out of control. Today, huge sections of the unthinned State Forest look as barren as winter all year long.
But those who study the native biota in the skeletal stands of the forest come away astonished by what they find there. "The Vineyard, and the State Forest in particular, has the highest concentration of rare species in the state. And there's a lot of work to do," says Tim Simmons, restoration ecologist for the state Natural Heritage and Endangered Species Program. He counts at least thirty state-listed animals, insects, and plants in the forest, all of them dependent, directly or indirectly, on the fire denied them since the days of regular burning on the old Great Plain. "The only thing missing," he says, "is more frequent fire." Just about everyone who knows anything about the State Forest wants to get back to Great Plain habitat just as fast as possible.
Well, that's not quite right.
"We don't really target getting ‘back to' something," says Simmons. "We more or less reintroduce those processes and see what kind of trajectory it will take. If you look at the original descriptions of Gross and [William] Brewster and all the other people that wrote about the heath hen, and you look at what we have there now, all we have differently is that it's a
little thicker. It's a marvelously intact system that has things in numbers that you just don't see anywhere else in the New England landscape."
In a sense, the idea to restore the heath hen – more accurately, its nearest surviving counterpart in the genus – to a cleared, frequently burned, and considerably healthier habitat of scrub and heath would simply be to add one more creature to the things that you just don't see anywhere else in New England. It wouldn't happen for many decades; the landscape is nowhere near ready to support it. But when it came, the prairie chicken would be the most captivating and biologically significant living thing in the habitat – an "umbrella species," to hear proponents argue it, the one whose fate indicates whether everything else living beneath it is doing well.
"I'm intrigued by the idea that you could use a species as an umbrella species," says Christopher Neill, an assistant scientist at the Ecosystems Center of the Marine Biological Laboratory in Woods Hole. Neill has spent a great deal of time studying how cutting and burning affects plant life, and the water table, in the State Forest. He points to Yellowstone National Park as an example and says that if it could be managed in a way that supports grizzlies and wolves, "then you would be going an awfully long way towards preserving the amount and configuration of habitat that would benefit a very large number of species. So we have some models out there that tell us that this way of thinking is viable and important."
The whole idea to introduce the prairie chicken here one distant day is Tom Chase's. He's the eastern Massachusetts program director of The Nature Conservancy, and an Oak Bluffs native. The heath hen demanded more space for its survival than any other species on the Great Plain, he says, and adds: "If we put back enough habitat for those birds, then we'll have enough for everything else. The effect that I wanted is something that's memorable enough, hopeful enough, slightly outlandish enough to keep the public's attention on what it is we're trying to do."
What he's trying to do is to get everyone to think bigger. The lethal problem right now, he says, is that there is too much fragmentation of habitat, and too much micromanagement of the landscape. "My whole point," says Chase, "is that the way conservationists have been thinking is, ‘We need to save this piece of land over here – and oh, I found this moth, and now we have to manage with fire at this fire frequency, not the old fire frequency. Oh, and there's some lichen over here.' Next thing you know, you've got this museum exhibit of landscapes, each of which needs to be micromanaged for increasingly competitive reasons." He believes that an introduction of the prairie chicken, and successful management of it on a restored habitat regularly raked by prescribed burns, will indicate whether the whole of the landscape, not just disconnected bits and pieces, is in balance.
Chase publicly proposed the idea of an introduction in the May–June 1999 edition of this magazine. In those days he said that a first step would be to find out just how closely the heath hen was related in genetic terms to the greater western prairie chicken, to which it was assigned as a subspecies by William Brewster in 1885. The two birds looked mostly the same, behaved the same, boomed the same.
But genetically, it turns out, they hardly knew one another.
Eric Palkovacs, twenty-seven years old, is a doctoral student in the Department of Ecology and Evolutionary Biology at Yale and the lead investigator in the heath hen study, which was published in the July edition of Molecular Ecology magazine. (He examined birds collected by the Peabody Museum of Natural History at Yale, the Museum of Comparative Zoology at Harvard, and the Martha's Vineyard Historical Society in Edgartown.) What he found in slivers of skin taken from beneath the heath hen toe was, to the layman and even some scientists, Tom Chase among them, rather surprising: in genetic terms, the heath hen stood considerably further apart from the prairie chicken than the prairie chicken stands today from all the birds in its genus that Palkovacs examined – the lesser prairie chicken; the Attwater's prairie chicken, which faces extinction along the eastern Texas coastline; and even the sharp-tailed grouse.
"It gets at the question of what really is a heath hen," says Palkovacs. "Is the heath hen any prairie chicken that occurred along from perhaps Maine to North Carolina, including Martha's Vineyard, before Europeans extirpated them? Or is a heath hen that population that was on Martha's Vineyard from about 1870, when the mainland population went extinct, to 1932, when the last individual died?"
The findings may be skewed by several factors, Palkovacs says. For one, the only heath hen skins he could sample came from the Vineyard. No one started collecting them until the last flocks found themselves trapped here, and this leaves out the whole picture of the genetic makeup of the lost mainland populations. Furthermore, the bottleneck caused by the isolation of the last generations of heath hens on the Vineyard may have compounded the genetic difference between the Island heath hen and the surviving mainland birds. So what actually caused the profound mutational differences between Island birds and the rest of the genus is a mystery, and may always remain so.
Palkovacs examined DNA taken from a shared maternal (mitochondrial) gene that reaches backward – unscrambled by any reproductive combination with male genes – possibly to the earliest female ancestors of all the birds he sampled. What he saw suggests that there was no gene flow between the Island heath hen and these other species or subspecies in the genus going back perhaps to the advent of the white man – maybe even to the advent of the last ice age, which may have permanently cleaved the heath hen from all the grouse to the west. The Vineyard heath hen might be not a subspecies of the prairie chicken but – notwithstanding all the morphological and behavioral similarities, and depending on what sort of scientist you ask – a species in its own right. And this raises an important pair of questions that bear on whether an introduction of prairie chickens to Martha's Vineyard as an ecological equivalent of the heath hen should ever happen:
Would it help the Vineyard on the roadway to habitat restoration – or would it help a bird that may go the way of the heath hen if more habitat cannot be found for it? Palkovacs, calling himself an investigator, not an advocate, refuses to make a definitive call. But he frames the issue in these terms:
"The Vineyard may be a good place to see if the birds can adapt and survive. But it may not be the best place to actually say, ‘If you want to reestablish the greater prairie chicken, where is the best place to do that?' I would say it's probably not the Vineyard. It depends on what you want to accomplish. If you really want to accomplish a self-sustaining population of greater prairie chickens in the Northeast, it's not the Vineyard. If you want to gain attention to conservation issues in the Northeast, and play up the historical legacy of the heath hen, it is the Vineyard.
"I hope," he adds, "that people can help restore natural systems to a state that is more similar to what they were before Europeans mucked them up. And it's unclear whether restoring a population of prairie chickens to Martha's Vineyard could aid in doing that. If it could, then I would be for it; if it wouldn't achieve that goal, then I wouldn't be for it. And I don't think it's clear yet which way that would go."
Others, who've debated the question about whether the prairie chicken, a bird of the Midwestern grasslands, could or should try to adapt to the scrubby habitat of the Great Plain are themselves quite clear about which way it would go.
"I'll speak to this in no uncertain terms," says Paul Goldstein, assistant curator and head of the Division of Insects at the Field Museum of Natural History and faculty member at the Committee on Evolutionary Biology at the University of Chicago. Goldstein has done more entomological work in the State Forest than anyone. "I find that argument – I call it evolutionary resurrection. And I find it the most ridiculous thing I've ever heard. I don't think we do ourselves any favors when we talk about putting one species in another's place, and [then seeing if the place] makes the species turn into another species. It doesn't make any sense. . . . The idea that you can put a prairie chicken onto Martha's Vineyard and it will be a ‘proto–heath hen' is nothing short of ridiculous.
"To my mind, it's a question of history versus potential," Goldstein says. "All we have is history.
I think history is a pretty good judge. And saying that ‘Oh, maybe this has adaptive potential' – frankly, these data do not speak to that at all. These data speak to history; they do not speak to evolutionary potential or adaptive potential. Adaptation should not even enter into the frame of this."
Tom Chase hasn't given up – though he occasionally slips these days and refers to the introduction idea in the past tense. More often now his conversation moves beyond the lost bird to larger goals that he says must be achieved, with or without the prairie chicken: tying fragmented habitats together, figuring out ways to acquire and restore lands lost to development, and bringing affordable housing into the equation so a Vineyard middle class can afford to stay here and feel invested in what's being saved, cleared, burned, restored, and tied back together on these offshore lands.
It all falls under the rubric of a fairly new word in the Vineyard conservation lexicon: undevelopment.
"And it takes me to this one conclusion," says Chase. "And I can find no alternative to it – that somehow we have to find a way to economically undevelop land over time. It's that simple. It's more acute here on the Vineyard because we're an island, but I'm sure that in the long run we're going to need that approach all over North America in selected places. And so much of my attention has not been focused on the genetics of the prairie chicken or even on the habitats, because those are in the hands now of people who are much brighter than I am and have the tools to figure that stuff out. What I've been struggling with is ways to undevelop land. Because if we can figure out how to do that, we can always figure out where to do this."But until undevelopment begins, restoration is all we've got. And when restoration begins on a large scale on Martha's Vineyard, it will begin in the State Forest, whose acquisition and growth to 5,168 acres of permanently undeveloped land, protecting the Island's only freshwater aquifer, may be laid, gratefully, at the feet of an extinct bird. There's a Great Plain in there somewhere, and there's a lot of work to do to save a habitat that the old bird saved for us.
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