Of a Feather: Fire, the heath, and the hen

By BILL CHAISSON
By Bill Chaisson

I have been thinking about the heath hen lately. Why? Because it depended on the maintenance of open country at a particular successional stage, primarily by fire. This eastern subspecies of the greater prairie chicken (Tympanuchus cupido cupido), lived from southernmost New Hampshire to northern Virginia at the start of European settlement, but disappeared quickly through the 18th and 19th centuries. Why were they here in the East — their western counterpart survives on the Great Plains — and why did they go extinct?

Much of New England is presently in severe or extreme drought, according to the U.S. Drought Monitor (droughtmonitor.unl.edu). Although we tend to associate drought with the western two-thirds of the country, right now the signs outside our local fire stations show the risk of fire here in central New Hampshire to be “high.”

The nature of vegetative communities is in part due to the amount of rainfall that a region normally receives. At national scale, the average amount of rainfall decreases as you move from east to west. Today, along a wavy line through the Midwest forested land gives way through a transition to grassland. In the post-glacial period grassland extended into the east. Even forested regions are periodically subject to drought, and climate scientists project it will become more common across North America.

With a dearth of rainfall comes an increased susceptibility to wildfire. Since land plants first evolved, lightning has been starting fires in dry and resinous vegetation. “Fire ecosystems” evolved in which plants rely on conflagration to halt the advance of succession in spite of rainfall. This isn’t just a western phenomenon. Pine barrens, the natural habitat of the heath hen, persist in the East — e.g. outside of Albany, New York, in central New Jersey, Cape Cod — but they generally must be managed by means other than fire.

In addition to “natural” wildfire, the tribal peoples of eastern North America burned the land regularly in order to keep it clear for agriculture and for hunting game that preferred open habitat. See William Cronon’s “Changes in the Land” (1983) and more recently Charles C. Mann in his “1491” (2005) for an introduction to tribal stewardship practices.

According to Mann, diseases contracted through contact with early European explorers decimated coastal tribal communities in 16th-century New England. When English settlers arrived in the early 17th century, although they did not realize it, they found a formerly cultivated landscape that had been abandoned to rack and ruin after 70-80% of its stewards died.

This may have been the first blow to the heath hen populations, but relentless hunting, the encroachment of settlement and consequent fire suppression drove it to extinction on the mainland by 1870. It is thought to have ranged from Maine to Florida before European settlement, but post-contact pandemics and subsequent succession of grasslands and barrens that were maintained by tribal people may have contracted its range.

Pine barrens are also caused by poor soil conditions and were therefore largely spared from cultivation during the 18th and 19th centuries. Consequently, they were relatively thinly populated during the period of history when most Americans made their living from agriculture. Growing population, however, meant that the barrens were eventually surrounded by and partly penetrated by settlement, which led to fire suppression, just as it did in the western U.S. during the 20th century.

The pine or “heathland” barrens, also called sand plains, were home to heath hen populations along the East Coast. In addition to pines, these areas support scrub oak, various types of laurel (“heath”), and many grasses. One of the best places to explore this vegetative community today is the center of Martha’s Vineyard, where it is maintained through controlled burns.

The Vineyard was the last home of the T. cuspido cuspido and the story of its demise is tragicomic in the outsized amount of bad luck involved. A few dozen birds survived there after the late 19th-century extinction on the mainland, and a preserve was established in 1908. The island was, at the time, free of predators like raccoons, skunks and foxes, and like most gallinaceous birds, heath hens laid large clutches. By 1915 there were over 2,000 birds on the Vineyard.

Although the interior of the island — the site of the preserve — was relatively thinly inhabited, fire suppression was still in place to protect island communities. Consequently, when a wildfire broke out in May 1916, the accumulated tinder caused the burning of 13,000 acres, and killed one-tenth of the mature heath hens and all of that year’s young. Although there were no natural predators, dogs and cats took a continual toll. Finally, diseases transmitted by island domestic fowl, including turkeys, proved deadly to the wild fowl. By 1932 it was a population of one, a male nicknamed “Booming Ben.”

Populations of greater prairie chicken (T. cupido pinnatus) and the lesser prairie chicken (T. pallidicinctus) both survive in the Midwest, albeit in reduced numbers and with restricted ranges. Molecular genetic studies of those extant birds and tissue samples from preserved Martha’s Vineyard specimens suggest the eastern population was closely related, but it may have been as different from the western ones as it was from the lesser prairie chicken. This is one reason the Long Now Foundation thinks the heath hen is a candidate for restoration by means of biotechnology.

The foundation’s project, Revive & Restore, also has its eye on the passenger pigeon and the Labrador duck. It seeks to manipulate genomes to resurrect extinct taxa, but also to increase genetic diversity in critically endangered ones, like the black-footed ferret.

The heath hen also attracted their attention because conservation efforts on the Vineyard to restore and maintain the heathland habitat have been underway for decades. T. cupido cupido is regarded as an indicator species; if a restored heath hen population does well, conservationists will know that the habitat has been sustainably restored as well.

Bill Chaisson, who has been a birdwatcher since age 11, is a former editor of the Eagle Times. He now works for the Town of Wilmot and lives in Sutton.