The Life and Death of the Heath Hen

Matthew Kamm

February 1, 2015 8 MIN READ Feature Articles

Although Heath Hens were hunted from the earliest days of European colonization and assuredly before then by Native Americans, the birds persisted on the mainland until the nineteenth century, when hunting pressure extirpated the Heath Hen from most of its traditional haunts. Mainland Massachusetts saw the death of its last Heath Hen when the bird was shot near Northampton in the 1830s; by the 1840s, it had been extirpated from Connecticut as well. When 1870 began, no wild Heath Hens could be found anywhere in the mainland United States, nor would any be sighted there ever again.

The entire distribution of the Heath Hen was then restricted to Martha’s Vineyard and Naushon Island. Henry Davis Minot was told that it was extinct on Naushon, according to his 1876 work The Land-Birds and Game-Birds of New England. Since he also conjectured that it was extinct on Martha’s Vineyard at that time—it was not—this information should be taken with a grain of salt. William Brewster visited the Vineyard in 1890 and estimated that somewhere between 120 and 200 birds remained in what was, by that time, the only surviving population in the world. As if to illustrate the dangers of placing so many eggs in one basket, a fire swept across the island four years later. Nesting Heath Hens relied almost entirely on camouflage to protect themselves and their nests from danger and had an unfortunate tendency to sit tight on their nests in response to danger, a strategy that served them poorly against the threat of fire. Charles E. Hoyle, a noted sportsman and conservationist who was familiar with the Heath Hen, wrote that fall of finding “the skeletons of many birds destroyed in the fire; that where he had started a hundred birds the previous fall, he failed to start five.” (Forbush 1912) Three years later, in the fall of 1897, Mr. Hoyle and his hunting dogs could not find a single bird.

In an attempt to bolster the failing population and to continue providing sport for the avid hunters of the day, Greater Prairie-Chickens from farther west were released on Cape Cod and the Islands. They “undoubtedly bred” in 1898, according to Hoyle (National Rifle Association of America 1901). Regrettably, the plight of the Heath Hen and the first hints of its incipient extinction triggered a surge of egg collecting and hunting for skins. A bootlegged skin could net a poacher $30, or even as much as $100 in the later years of the bird’s decline. Of course, there were statutes in place to discourage such behavior, including a fine of $20 if a poacher were caught. The economics of such a system had obvious implications for the beleaguered Heath Hens, and many concerned citizens began agitating for more stringent protection at the dawn of the twentieth century. In response, the Commonwealth of Massachusetts closed the hunting season on the bird entirely for five years and raised the fine for infractions to $100. After another fire, a 1907 estimate for the state Commissioner of Fish & Game estimated the remaining number of Heath Hens to be fewer than 80; only 21 birds were counted on the survey (Gross 1928).

Heath Hen Reservation: A map of Martha’s Vineyard with the Heath Hen Reservation in the center, circled. Attribution: Gross 1928

Also in 1907, John E. Howland of Vineyard Haven and others succeeded in convincing the Commonwealth of Massachusetts to create a Heath Hen reservation on Martha’s Vineyard consisting of 1600 acres of land under special protection. It proved to be a favorable year for breeding, and the Heath Hens increased to almost 100. Dr. George W. Field counted 77 individuals (Gross 1928). For a time, all proceeded amazingly well. By 1910, the newly created reservation was home to an estimated 300 birds. Forbush visited the island in 1916 and personally noted approximately 800 Heath Hens, estimating that the whole island’s population must have been nearly 2000 birds—a spectacular increase from their near-extinction levels less than two decades earlier.

Hopes for saving the Heath Hen were at an all-time high when disaster struck once again. A fire broke out on the breeding grounds during a May gale in 1916. The winds drove the fire into a conflagration that swept all across the interior of Martha’s Vineyard, killing large numbers of birds and depriving the survivors of food and cover. The latter issue would prove particularly critical as the following winter saw an irruption of Northern Goshawks (Accipiter gentilis), which preyed heavily on the surviving birds. The next year, Forbush visited the Vineyard again to aid the reservation managers in assessing the damage. He estimated that fewer than 100 birds still lived (Forbush 1927).

What could the beleaguered reservation managers and the state do to save the bird now? The specter of extinction loomed larger than ever before, and desperate times called for desperate measures. Transplants of Martha’s Vineyard birds were attempted to ancestral breeding grounds on Long Island; none of these survived to reproduce. Birds were taken into captivity to attempt captive breeding, which also failed.

Heath Hen Population Trends: A graph created by Alfred O. Gross for his 1928 monograph on the Heath Hen, showing the population trend over the last four decades of the bird’s existence. Attribution: Gross 1928.

Dissections after the fact revealed that the males’ testes had not developed for the breeding season, possibly due to a lack of the green sorrel and clover that made up their typical spring diet, or possibly due to being restricted in cages and unable to perform their normal lekking activity (Gross 1928). All of the birds taken from the wild for transplants and captive breeding decreased the wild breeding population still further. After reaching a peak of over 400 birds in 1920, the population began its final decline to extinction. A series of cold, wet breeding seasons limited productivity and resulted in high chick mortality (Forbush 1927).

By 1928, no broods had been seen on the island for several years, and only a single living Heath Hen was known to exist. Nicknamed “Booming Ben,” he became something of a media celebrity as the last of his kind, much like “Lonesome George” the Pinta Island Tortoise was until his death in 2012. Booming Ben would appear at the lekking site year after year, alone, tooting and stamping for females that would never arrive. For four years he tried in vain to attract a mate, and in March of 1932, he disappeared into the scrub of Martha’s Vineyard and was never seen again. So ended Tympanuchus cupido cupido, despite tens of thousands of dollars (before adjusting for inflation) and countless hours spent on its protection.

What went wrong? Some of the causes for the death of the Heath Hen are obvious. The species was hunted indiscriminately for almost all of its existence. Laws were enacted for its protection as early as the 1790s, but enforcement was difficult and penalties were so minor that they were largely ignored. Forbush pointed out that, although the Heath Hen was legally protected from hunting by closed seasons in Massachusetts, “these acts permitted any town to suspend the law within its own limits by a vote of any regularly called town meeting. Some towns took advantage of this, thus "nullifying the law in the only towns where the birds still existed” (Forbush 1912). Even on the Vineyard, authorities found enforcement almost impossible; the difference between a would-be Heath Hen poacher and a law-abiding duck hunter on his way to the shoreline was only one of intention. Even a poacher caught red-handed with a Heath Hen in his bag could be penalized only, not retroactively prevented from killing the bird.

Heath Hen Display: A Heath Hen performing its courtship display, with neck feathers (pinnae) erect and air sacs inflated. Source: www.lostbirdfilm.org

In my opinion, the reduction of the Heath Hen’s range to a single island doomed the species more effectively than a legion of hunters. It is not my intention to minimize the incredible efforts of those who worked to save the Heath Hen, nor to malign the conservation ethic of the people of Martha’s Vineyard who rallied with remarkable amounts of monetary and volunteer support when they learned of the Heath Hen’s plight. The fact remains, however, that an isolated population will always be vulnerable to what ecologists refer to as stochastic events—simply put, the vagaries of random chance. A bad fire year followed by an upswing of predators killed thousands of birds. A few years of bad weather prevented effective recovery.
With no other populations as a source for immigration to buffer these birds against misfortune, it was only a matter of time before extinction claimed them.

The specific mechanisms behind the Heath Hen’s demise are largely theoretical, but no less interesting to consider, especially given the current status of another Greater Prairie-Chicken subspecies, the Attwater’s Prairie-Chicken (Tympanuchus cupido attwateri) of coastal Texas and Louisiana. Midsized mammalian predators took their toll on Heath Hens. Cats were often found on the reservation, and the reservation’s caretakers devoted quite a lot of time to the hunting of cats, rats, hawks, and other natural enemies of the Heath Hen (Gross 1928). Less obvious, but no less deadly, were the threats of disease and skewed sex ratios. Poultry blackhead disease, a nasty and often fatal malady carried by a protozoan transmitted by a nematode worm, is infamous for its ability to spread among free-living poultry flocks. The manager of the Heath Hen reservation kept geese on the land and allowed them to forage across the same fields as the Heath Hens. Blackhead disease was confirmed in a male Heath Hen in 1923; the last time that any broods of young birds were seen on the island was two years later in 1925 (Gross 1928). Considering that young birds are often the most susceptible to blackhead disease, this could have been a major contributing factor to the bird’s final decline.

Compared to a killer protozoan, a skewed sex ratio might not seem like cause for alarm, but the Heath Hen’s mating system rendered it susceptible to disaster in this regard. On the lekking grounds, a successful male might mate with several females, but each female would mate with only one male (as far as we know). Even if many male birds are killed, a small number of males can mate with a large number of females, thus ensuring the future of the species. Unfortunately, the reverse is not true. If females die disproportionately often, having lots of males does not make things better. Alfred Gross, writing in his 1928 monograph on the species, theorized that the females’ habit of sitting tight against danger meant that they died in larger numbers than the males did when fires swept the reservation.

Further, Gross mentions an unsettling behavior common in other gallinaceous birds when there are an excess of males in the population: males will find nesting females and harass them by attempting to mate with them and destroy their nests in order to father the next brood. Females can be injured or even killed if large numbers of thwarted males roam the landscape looking for these illicit opportunities, to say nothing of the damage to eggs and young. No less a conservationist and sportsman than Aldo Leopold wrote in Game Management (1986) that, “A heavy excess of males is definitely known to have been associated with the decline of the Heath Hen and possibly represents the final cause of the decline.”
In the end, a combination of factors led to the Heath Hen’s demise, but foremost was the dramatic reduction of its range to a single island. Today, many birds of shrubland and open habitats are facing similar challenges; their ranges of suitable habitat are shrinking, which forces them out of their ancestral strongholds. If we are wise, we will learn from the example of the Heath Hen, and protect these birds and their habitats before they become so rare and restricted that not even a herculean effort can do more than delay the inevitable.

Citations

• Forbush, Edward Howe et al. 1912. A History of the Game Birds, Wild-Fowl and Shore Birds of Massachusetts and Adjacent States... with Observations on Their...recent Decrease in Numbers; Also the Means for Conserving Those Still in Existence. Boston: Wright & Potter printing company, state printers.
• Forbush, Edward Howe. 1927. Birds of Massachusetts and Other New England States. Norwood, Massachusetts: Norwood Press.
• Gross, Alfred O. 1928. The Heath Hen. Memoirs of the Boston Society of Natural History, 6 (4): 491-588. Boston: Boston Society of Natural History.
• Leopold, Aldo. 1986. Game Management. Madison, Wisconsin: University of Wisconsin Press.
• Minot, H. D. 1876. The Land-Birds and Game-Birds of New England; with Descriptions of the Birds, Their Nests and Eggs, Their Habits and Notes. Boston: Estes & Lauriat.
• National Rifle Association of America. 1901. American Rifleman.

Matthew Kamm is a graduate student pursuing his Ph.D. at Tufts University in the lab of Dr. Michael Reed. His research interests include the decline of the American Kestrel as well as general risk factors surrounding extinction in birds. He was a lead writer for Mass Audubon’s Breeding Bird Atlas 2 and State of the Birds publications, and loves to get outside and go birding whenever his graduate student schedule allows.