540 The Roller-like Birds 



cha, cha-cha" and is not unpleasant in sound. Its food consists almost en- 

 tirely of insects, especially grasshoppers and large beetles. The favorite nesting 

 sites of these remarkable little Owls are deserted Woodpeckers' holes in the 

 giant cactus, rarely in holes in trees, such as cottonwood or mesquite. There 

 is no nest, the eggs, which number from two to five, being deposited on a few 

 chips at the bottom of the cavity; both parents assist in incubation, which lasts 

 about two weeks. The other species is the Socorro Elf Owl (M. socorroensis) of 

 Socorro Island, western Mexico. 



THE GOATSUCKERS AND THEIR ALLIES 



(Suborder Caprimulgi) 



The third of the suborders into which the Coraciiformes is divided, is a rela- 

 tively small, though widely spread, group of medium-sized birds known variously 

 as Goatsuckers, Nightjars, Frogmouths, etc. They have rather compact bodies, 

 with short legs, long, pointed wings with ten primary quills, a widely gaping 

 mouth, and generally softly tinted gray and brown plumage ; the tail-feathers are 

 ten in number. They are further distinguished structurally by having the skull 

 holorhinal, that is, with the nasal bones only slightly or not at all cleft, the organ 

 of voice (syrinx) bronchial, and the oil-gland nude, when present, while the after- 

 shaft to the feathers is present, though small, and the blind intestine (caeca) 

 present and functional. The young are hatched helpless, but covered with down, 

 and all the members of the suborder are crepuscular and nocturnal. 



As regards the position of this group, Mr. Beddard says: "The relationship 

 of the Caprimulgi to other groups is a puzzle hard of solution. This is partly, 

 perhaps, due to the fact that the Goatsuckers are probably a somewhat ancient 

 group." He decided, from all the evidence, that their nearest relatives are the 

 Owls, a conclusion which "is in harmony with much recent opinion, and is 

 curious in view of the external likenesses which bind together the two groups of 

 birds, likenesses which might fairly be put down to similarity of habit. These 

 superficial resemblances are, however, enforced by more deep-lying structural 

 similarities." Of these it may be mentioned that the Owls come nearest to them 

 in the "primitive character of the gut, while the caeca, swollen at the ends, are 

 alike in both. The Owls, too, are nearly the only other coraciiform birds besides 

 the Caprimulgi, which have well-defined basipterygoid processes." 



The Caprimulgi is divided into three families the Steatornithida, which 

 comprises only the peculiar Oil-bird, the Podargidce, or Frogmouths, of which 

 there are three genera and about thirty-five species, and the Caprimulgidce, or 

 Goatsuckers or Nightjars. The latter family is separated into two well- 

 marked subfamilies the Caprimulgince and Nyctibiince, and comprises 

 twenty genera and about one hundred and twenty-five species and subspecies. 

 The characters separating them are described more fully later. 



