98 BIRDS OF SOUTH DAKOTA 



420a. Western Nighthawk (Chordeiles virginianus henryi.) 



A subspecies, very common west of the Missouri River 

 and not rare in the eastern part of the State. Similar to the pre- 

 ceding but lighter, more buffy both above and below. 



420c. Sennett's Nighthawk (Chordeiles virginianus sennetti.) 



Another subspecies of the Nighthawk family, but smaller 

 than the preceding, and the palest of them all in color. It is 

 also a bird of the plains, but it seems to follow the foothills of 

 the mountainous districts more closely than the other species. 



A summer resident. Habits the same as the others. 



FAMILY MICROPODID^. SWIFTS 



Two species of Swifts live in our State during the summer. 

 They are well named, as few birds can surpass them in speed, 

 and they spend most of the day on the wing hunting for insects. 



One noticeable characteristic of the Goatsuckers and 

 Swifts is their very small feet. Thev are all valuable birds as 

 insect destroyers. 



423. Chimney Swift (Chaetura pelagica.) 



Before chimneys came to this country these insect eaters 

 slept and rested in hollow trees ; now they may be seen at dusk 

 by hundreds circling over buildings and, one by one or by twos 

 or threes, dropping into high chimneys, where they perch for the 

 night, clinging to the sides. Their feet are so small that they 

 can perch only by clinging, supported by their stiff, spiny tail 

 feathers. It has been said that they can fly all day without rest- 

 ing, living literally on the wing. They even break off the small 

 twigs of which their nests are built as they fly past dead tree 

 tops. These twigs are glued together and to the inside of the 

 chimney with a saliva which they secrete. 



The Chimney Swifts are about five inches long from tip 

 of tail to end of bill, but their wings are unusually long and ex- 

 tend beyond the tail. Above, greenish black or dark gray; belly 

 lighter but gray at throat. A summer resident. It is not known 

 yet where they pass the winter. 



