OTIS 139 



Genus OTIS. 



This genus is now generally divided into two, Otis, confined to 

 Otis tarda and its first cousin Otis dyhowshii, and Tetrax which 

 contains only the Little Bustard, Tetrax tetrax, and the eastern 

 subspecies orientalis. There is but little outward difference, how- 

 ever, in these two genera beyond size, and I retain Blyth's classifica- 

 tion for these bustards and place both our birds in the one genus. 



The genus Otis may be distinguished from the other genera of 

 this family by the fact that the crown of the head is never black, and 

 only very short-crested, and the short, stout tarsus is only equal to 

 one-fourth of the length of the wing. 



The Great Bustard, Otis tarda, has practically no seasonal change 

 of plumage, but the male of the Small Bustard, Otis tetrax, has one. 

 Again, whereas the male of Otis tarda is much bigger than the 

 female, the female of Otis tetrax is certainly as large as the male 

 and sometimes somewhat larger. 



Keij to Species. 



Wing over 15 inches, generally between 18 and 25l . . Otis tarda. 

 Wing under 15 inches, generally between 9 and 11 . . Tetrax orientalis. 



