BLUE BIRD. 
23 
FAMILY II. SAXICOLIDiE. THE ROCK INHABITERS. 
Marginal indentations of sternum exceeding in depth the height of the keel, hut the width of the sternum is more than 
half the length of the keel. Tail square and somewhat emarginate. 
This family differs from that of Turdidce in having the sternum wider in proportion to its length. The tail is also 
square and emarginate, while in Turdidce it is always rounded. 
GENUS I. SIALIA. THE BLUE BIRDS. 
Gen. Ch. Predominating color above, blue. 
SIALIA SIALIS. 
Blue Bird. 
Sialia sialis Baird, Birds of North America, 1858, 222. 
DESCRIPTION. 
Sr. Cii. Eorm, somewhat robust. Bill, not very slender; gently curved at the tip, and slightly notched. Tongue 
acuminate, bifid, and fringed with rather coarse cilia at the end. Sternum, quite strongly built. 
Color. Adult male in spring. Above, uniform dark blue, with the tips of the primaries, secondaries, and inner 
edges of the tertiaries, dark brown. The ends of the tertiaries, secondaries, primaries, and tail, are narrowly edged 
with white. Lores and ear coverts, dusky. Chin and sides of the throat, blue; this color sometimes extends over 
the entire throat, and, in some specimens, even reaches the upper part of the breast. Breast, sides and flanks, rich 
chestnut-brown, with the abdomen dirty white. The under tail coverts are pale blue. Tibiae, dusky. Under wing 
coverts, axillaries, and under portion of the tail, blue, of a lighter shade than the upper parts. The remainder of 
under side of wings, glaucous. 
In autumn there is a reddish suffusion over the upper surface, and less dusky about the sides of the head. 
Adult female in spring. Above, pale blue, becoming brighter on the wings and upper side of the tail. There is 
a reddish wash over the middle of the back, and on the shoulders. The ends of the wings are colored as in the male. 
Sides of the head, dusky. Chin, throat, abdomen, and under tail coverts, dirty white; remainder of under portions 
of the body, chestnut, as in the male, but paler. Axillaries and under wing coverts, bluish-white. Tibiae, dusky. 
In autumn the chin and throat are like the breast; the white of the abdomen and under tail coverts is purer. 
Young male, differs from the adult in having a whitish wash over the breast. There is also a more rufous 
suffusion above. The tertiaries are edged with reddish and white, and the entire colors are paler. 
Young female, darker above than the adult, with the tertiaries edged with rufous and white. A reddish wash 
extends over the head and back. The chin and throat are like the breast. The white of the abdomen is purer, while 
the under tail coverts are strongly tinged with buff. 
Nesting plumage of male. Tail and wings like the young in autumn. The remainder of upper surface dull reddish 
brown, streaked with whitish; two rows of coverts are also tipped with it, forming bars across the wings. Under 
portions, whitish; with the feathers of the throat, breast, and flanks edged with brownisli-red. Tibim, white. 
Female in nesting plumage, similar to the male, but with colors paler. Irides, brown. Bill and feet, black in 
both sexes, and in all stages of plumage. 
OBSERVATIONS. 
There are two western representatives of this species ( Mexicana and arctica ), but it may be distinguished from 
them by its uniformly blue back, combined with the red breast and throat; although I have seen specimens of sialis 
having a blue throat, which closely approached some specimens of Mexicana. Females of Mexicana are paler than of 
sialis. Specimens found breeding in Florida are not only smaller in size, but darker in color throughout, than those 
from New England. This species has a wide distribution, extending from latitude 46,° south to the extreme limits 
of the main land of Florida, and west to about longitude 102.° They winter in the Southern States and the West 
Indies. 
DIMENSIONS. 
Average measurements of seventeen specimens from Florida.—Length, 6-60; stretch, 12-37; wing, 3-89; tail, 
2-G3; bill,-51; tarsus, -76. Longest specimen, 7-00; greatest extent of wings, 12-95; greatest length of wing, 4-20; 
of tail, 3-55; of bill, -55; of tarsus, -80. Shortest specimen, 6-50; smallest extent of wings, 11-60; smallest length 
of wing, 2-60; of tail, 2-40; of bill, -50; of tarsus, -70. 
Average measurements of seventeen specimens from New England.—Length, 6-74; stretch, 12-50; wing, 4 53; 
tail, 2-50; bill, -50; tarsus, -77. Longest specimen, 7-70; greatest extent of wings, 13-25; greatest length of wing, 
4-20; of tail, 3-15; of bill,-51; of tarsus,-82. Shortest specimen, 6-31; smallest extent of wings, 11-40; smallest 
length of wing, 2-85; of tail, 2-30; of bill, -50; of tarsus, -70. 
