256 
BIRDS OF PENNSYLVANIA 
Genus TACHYCINETA Cabaiks. 
Tachycineta bicolor (Vieill.). 
Tree Swallow ; White-bellied Swallow. 
Description {Plate 38). 
Length about 6 inches ; extent about 13 inches ; tail slightly forked ; bill black ; 
legs and iris brown ; lores black ; above glossy metallic-green ; wings and tail black- 
ish, with faint greenish gloss ; lower parts entirely white. 
Young, colors are duller and toes somewhat yellowish. 
Habitat. — North America at large, from the Fur countries southward, in winter, to 
the West Indies and Central America. 
The Tree Swallow, when flying- or at rest, can easily be distinguished 
from all other of our swallows by its dark-colored back and pure white 
under parts. This species arrives here late in March or early in April, 
and leaves in September. Common and very generally distributed 
during migrations ; as a summer resident seems to be most frequent 
about rivers and other large bodies of water. From numerous reports 
before me it is learned that this swallow breeds more or less regularly 
and rather sparingly in nearly every county in the state. Referring to this 
bird in Lycoming county, my friend Prof. A. Kock writes in a letter of 
recent date substantially as follows : It used to breed readily in boxes, 
but not since the sparrow nuisance has been introduced from England. 
Have observed the female Tree Swallow enter the dry limbs of high trees 
(buttonwood) on our river islands. Think we have more some years 
than others. 
Genus CLIVICOLA Forster. 
Clivicola riparia (Linn.). 
Bank Swallow ; Sand Swallow. 
Description {Plate 90). 
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. 
Habitat . — Northern hemisphere; in America, south to the West Indies, Central 
America and northern South America. 
Common summer resident at many points along Delaware, Susque- 
hanna and other large streams. 
