BIRDS OF PENNSYLVANIA. 207 



GENUS CL.IVICOLA. FORSTER. 



616. Clivicola riparia (LiNN.). 



Bank Swallow. 



DESCRIPTION. 



Smallest of all our Swallows ; length about 5, extent about 12| inches : bill black ; 

 legs brownish ; iris dark-brown ; tail short and slightly forked ; lower part of tarsus 

 feathered behind ; above grayish-brown ; beneath white, with a broad band across 

 the breast, same color as on back ; wings and tail dark brown. 



Hab. Northern hemisphere; in America, south to the West Indies, Central 

 America and northern South America. 



GENUS STELGIDOPTERYX. BAIRD. 







617. Stelgidopteryx serripennis (Auo.). 



Rough-winged Swallow. 



Rather larger than the last ; bill, legs and eyes same color as the Bank Swallow ; 

 above grayish-brown ; lower parts similar, though paler, gradually whitening on the 

 belly ; edge of first primary rough to the touch, by the outer web being converted 

 into a series of stiff recurved hooks. The design of this peculiar wing structure is 

 not clearly known. It has been suggested that these hooks "assist the birds in 

 crawling into their holes, and in clinging to vertical or overhanging surfaces." 



Hab. United States at large (in the Eastern States north to Connecticut), south 

 to Guatemala. 



The Bank and Rough-winged Swallows arrive here about the first 

 week in April and remain with us until about September 1. Both 

 species frequent the same localities, being found generally in the 

 neighborhood of rivers, large creeks and mill-dams. These birds are 

 not only alike in habits, but they also greatly resemble each other in 

 size and colors. The Bank Swallow has a white throat and a dark 

 band across the breast. The Rough-winged has a uniform mouse- 

 colored throat and breast. These throat and breast markings will 

 sometimes enable you to recognize the birds in life. Should you, how- 

 ever, desire to positively determine these two species, my advice would 

 be, take your gun and shoot them. After doing this you will know 

 the Bank Swallow by a tuft of feathers on the tarsus, near the inser- 

 tion of the hind toe. An adult Rough-wing (particularly if an old 

 male) has the first wing quills furnished with a number of saw-like 

 hooks, from which originate the common name, likewise the technical 

 one serripennis, but as the immature Rough-winged Swallows lack 

 these curious hooks, look at their legs a Rough- winged Swallow has 

 no feathers on the leg just above the hind toe. 



