422 Birds of Colorado 
Bank-Swallow. Riparia riparia. 
A.O.U. Checklist no 616—Colorado Records—Aiken 72, p. 198; 
Cooke 97, pp. 19, 111; Rockwell 08, p. 175; Henderson 09, p. 238. 
Description.—Male—Above dusky brown, becoming dusky black 
on the wings and tail, but without gloss; below white, except for a 
broad band of greyish-brown across the chest, extending back along 
the flanks on either side ; a tuft of feathers on the tarsus, pale buffy ; 
iris brown, bill black, legs dark horn. Length 4.90; wing 4-15; tail 
2-10; culmen -25; tarsus -40. 
The sexes are alike. The young birds have the feathers of the back 
and upper tail-coverts, also the inner secondaries and wing-coverts, 
tipped with buffy-white and the chin tinged with buff. 
Distribution.—The Bank-Swallow, or Sand-Martin as it is called in 
England, has a range perhaps more extensive than that of any other 
Passerine bird. It breeds throughout Europe, northern Asia and 
North America, in the latter continent from the Arctic regions to 
Georgia and northern Mexico; it goes south in winter to southern 
Asia and Africa, and in America to the West Indies and through 
Central America to Peru and Brazil. The Bank-Swallow is quite a 
rare bird in Colorado, or else it has generally escaped the notice of 
observers. Aiken (72) records it as first noticed on April 26th in the 
Fountain Valley, and there is one example in the Aiken collection 
from Fremont co., dated May 16th. Dennis Gale notes its arrival 
in the Boulder Valley April 20th, but Henderson considers this record 
doubtful ; Rockwell reports that Sullivan found it reasonably plentiful 
near Grand Junction, arriving May lst and departing September Ist. 
This is the extent of the information available. 
Habits.—The Bank-Swallow breeds in large colonies, 
making horizontal holes or burrows in sand-banks, 
generally along streams, but often too in railway cuttings ; 
the eggs, four to six in number, are white with a rosy 
tinge when unblown, and measure on an average °69 x 
‘49. Sullivan dug out of a bank on the Gunnison 
River, July 2nd, 1904, six young ones ready to fly. 
Genus STELGIDOPTERYX. 
Rather small Swallows—wing under 4-5—with slender bills and 
rounded, superiorly directed nostrils without an operculum; outer 
primary with the tips of the barbs of the outer web produced and 
recurved, so as to form a series of clinging hooks along the outer edge 
of the wing ; this structure is only fully developed in the male, in the 
