HEATH HEN 279 



scrub-oak plains of Marthas Vineyard Island. It is a striking ex- 

 ample of a bird that has not been able to adapt itself to the changing 

 conditions brought about by civilization. 



Audubon (1840) wrote: "We frequently meet with the remains of 

 such [heath hen] as has been destroyed by the domestic cat which 

 prowls in the woods in a wild state." What was true in Audubon's 

 day was true in the more recent years of the heath hen, when cats 

 ranked high among the enemies of the bird. In addition to the cats 

 reared on the island, large numbers were introduced by people who 

 dumped them in the interior of the island when they left their sum- 

 mer homes in autumn. A large part of the effort of the State De- 

 partment and the special wardens in the control of vermin was 

 directed toward the semiwild house cat. 



Large numbers of hawks are attracted to the island because of 

 the abundance of mice and shrews, which live among the scrub oaks. 

 Unfortunately, many of the hawks, for example the marsh hawk, 

 which have a good reputation elsewhere, are frequently tempted, on 

 Marthas Vineyard, to prey upon birds ; and when the heath hen was 

 common, these birds were also numbered among their victims. The 

 goshawks, notorious for their killing of game birds, played their 

 part in the history of the heath hen. The most notable instance of 

 their wholesale depredations was in the winter of 1916-17, following 

 the destructive fire that swept over the island during the preceding 

 spring. Other hawks, such as the red-shouldered, the rough-legged, 

 the pigeon hawk, and others, as well as the different species of owls, 

 were killed on sight by the wardens in charge of heath-hen protec- 

 tion. It is probable that the wholesale killing of hawks and owls so 

 upset the balance of nature that it acted as a boomerang to the heath 

 hen. 



Disease was one of the most important factors in the recent de- 

 cline of the heath hen and was one that man was unable to control. 

 Blackhead is a disease common to poultry, but, so far as we know 

 at present, it is unusual in birds living in a free, wild state. The 

 heath hen, however, had the peculiar habit of congregating in the 

 open fields near farmhouses where poultry was kept. In most in- 

 stances, chickens and turkeys had access to the fields visited by the 

 heath hen, and thus the dreaded disease was readily transmitted 

 to the native birds. Blackhead was found in the adult heath hen, 

 and this is presumptive evidence that the disease was very destruc- 

 tive to the young. 



Internal and external parasites were found on the few heath hens 

 examined, but these were all of minor importance as compared to the 

 disease blackhead. 



In the recent history of the heath hen it was well known that there 

 was a great excess of male birds. This abnormal ratio may have 



