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/E. 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. They are all valuable birds as 
insect destroyers. 
423. CuHrimney Swirt (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. 
