290 TACHYERES CINEREUS 



GENERAL HABITS 



The Steamer Duck has aroused the interest and wonder of all travelers in the 

 Straits of Magellan and among the Falklands from the earliest times to the present. 

 The first mention of it was made by Pedro Sarmiento de Gamboa, who, writing in 

 1580, describes its peculiar habit of racing over the water at an astonishing speed. 

 In 1740 the survivors of the Wager were forced to resort to the use of this duck as 

 food, and later in the eighteenth century Pernetty and Captain Cook described its 

 habits (Cunningham, 1871). Darwin wrote about it in his account of the voyage of 

 the Beagle. 



Several pages could be written on the question whether or not there is more than 

 one species of Steamer Duck, but this would not lead us much nearer a solution, for 

 the necessary evidence has not all been collected. A careful study of a large number 

 of specimens and all of the literature has finally convinced me that we cannot ex- 

 plain all the observed facts in field or museum on the basis of a single stable species. 

 The data will be found recorded at some length under Description. Briefly, my 

 reasons for this conclusion, which differs from that expressed by me in the Ibis for 

 1917 (page 116), are somewhat as follows. 



First, we have the old, very large and white-headed type with yellow bills in both 

 sexes which mate and apparently (always?) produce flightless young very clumsy 

 and much like themselves. These adults are extremely large, always flightless and 

 therefore strictly coastal in distribution, but their wings are not only very much 

 smaller, relatively speaking, than they ought to be, but they are actually shorter by 

 several centimeters than they are in the much smaller red type (Tachyeres pata- 

 chonicus) . If we classify the small red types as merely younger stages, then we must 

 explain why the wing, instead of growing somewhat longer with age as it does in all 

 other Anatidae, does in fact get shorter! This I think is the greatest stumbling block 

 to the one-species theory. 



Second, we know that birds of the red type do mate and produce young and it is 

 more than doubtful whether all these red birds are really young at all. They do not 

 have this appearance, they are uniform in first plumage and some have large carpal 

 spurs. They are smaller by two to four pounds than the gray types, but their wings 

 are longer. 



Third, we have some evidence from field observers and collectors who are well 

 qualified to judge, that there are two species, or at least one species which is very 

 variable and peculiar. Mr. Blaauw (1916a, 1921) stoutly maintained after his trip to 

 Tierra del Fuego that there are two species. His life-long familiarity with the 

 swimming birds entitles his opinion to much respect. Mr. R. H. Beck, who has 

 written me at length and whose field notes I have carefully read, thought that there 

 were two species (or at least a species and subspecies) and his opportunity for seeing 



