Fig. 13.—General North American distribution of the rough- 
winged swallow. The outlined range may include large sections 
in which populations of the species aré thin or even absent, be- 
cause of the nature of the terrain and paucity of suitable hab- 
itat. The species also breeds widely in South America. The 
break in the range at Panama marks the suspected southern 
: limit of winter range of North American populations. 
Hess (1910) found that rough-wing burrows were 
not generally as deep as those of the bank swallow. 
Only a few rough-wing burrows have been measured, 
nearly all in nothern Illinois. They varied in depth 
from 10 inches to 3 feet, 18-20 inches being most 
common. 
A photograph of a nest with eggs, removed from 
the burrow, was published by Hess (1909). Four 
nests were described as being made of dry grass, 
corn leaves and husks, and weed stems and _ root- 
lets (Loucks, unpublished notes 1891, Blocher 1922, 
and Goelitz 1915). 
The nesting cycle of this species has received 
almost no attention in Illinois. Egg laying spans 
from at least May 7 to June 14 in northern Illinois 
(Fig. 14). Clutch sizes in 14 nests varied from 
| BREEDING + 
— WINTER 
+ 
"Several Thousand if 
MIGRATING 
1,000: 
500 = 
g NORTH = 
* % 
100 * *, 
EGG aA her * 
e I\ 
nN e 
7 i °, on / \ . eae *\ * 
< 1020) 30 9 19 29 9 \9 29 lO 20 9 19 29 10 20 30 10 20 30 
id MAR APR MAY JUN AUG SEP OCT 
¥ CENTRAL 
(2) 
a 
2 
Oo 
n 
[=] 
& 
v4 e 1300 
1,000: 
500 SOUTH 
je) lo) fe) 9 19 29 9 iS co 10 20 9 e) ap 10 20 30 10 20 30 
MAR APR MAY JUN AUG SEP OCT 
Fig. 14—Egg-laying and migration seasons of the rough-winged swallow in different areas of the state (see Fig. 1). Spring and 
gtaph lines (1967-1970) show the highest daily count of each 2 days (left scale). Asterisk symbols represent counts made in 
“T years or by other observers. Shaded areas show the span of dates during which egg laying has been recorded. Dot symbols 
“sent counts made on the western side of the state; lines without dots represent the eastern side. Arrow symbol indicates date 
ctual migration. 
