Cliff-Swallow 415 
The nest is composed of various materials loosely 
thrown together, such as dry grasses, straw, leaves, 
etc., etc., and is warmly lined with feathers. The eggs, 
four to six in number, are creamy-white, and measure 
“97 x 70. 
Genus PETROCHELIDON. 
Swallows of moderate size—wing under 5-0—with small and tri- 
angular-shaped bills, with the culmen straight to near the tip, which 
is abruptly decurved ; nostrils large, rounded and superior, without 
operculum ; tail short, less than half the wing and even; rectrices 
not tapering, but broad and rounded at the tips ; tarsus shorter than 
the middle toe and claw ; the middle and outer toes adherent basally. 
Sexes alike; eggs spotted. 
This genus, containing the Cliff-Swallows, ranges over temperate 
and tropical America, South Africa, India and the Indo-Malayan and 
Australian regions. Only one species is found in North America. 
Cliff-Swallow. Petrochelidon lunifrons. 
A.O.U. Checklist no 612—Colorado Records—Say 23, vol. ii, 
p. 47; Allen 72, pp. 148, 156, 162; Aiken 72, p. 198; Henshaw 75, 
p. 215; Scott 79, p. 93; Tresz 81, p. 288; Allen & Brewster 83, 
p. 260; Anthony 85, p. 152; Drew 85, p. 15; Morrison 88, p. 73; 
Kellogg 90, p. 89; Lowe 92, p. 101; McGregor 97, p. 38; Cooke 97, 
pp. 18, 110, 217; Keyser 02, pp. 118, 263; Dille 03, p. 74; Henderson 
03, p. 236; 09, p. 238; Warren 06, p. 23; 08, p. 24; 09, p. 17; 
Gilman 07, p. 194; Markman 07, p. 157; Rockwell 08, p. 175. 
Description.—Adult—Crown glossy blue-black, abruptly defined 
from the frontal patch, which varies from dull white to drab-brown ; 
back also glossy blue-black, but slightly streaked with grey and 
separated from the crown by a double collar of rich chestnut followed 
by grey, the former continuous with the ear-coverts ; cheeks and throat 
also a rich chestnut ; wings, tail and upper tail-coverts dusky black, 
rump light cinnamon-rufous ; below paling from the chestnut throat 
to greyish-brown on the breast, and white on the abdomen and flanks ; 
some of the under tail-coverts brown margined with white ; a glossy 
blue-black patch on the lower throat; iris brown, bill black, 
jegs dusky. Length 5-5; wing 4-5; tail 2-20; culmen -30; 
tarsus -45. 
The sexes are alike ; young birds are duller than the adults, and have 
no glossy blue-black ; the forehead is often chestnut, and the sides 
of the head and throat dusky brown. 
