t> 412 
BIRDS OF PENNSYLVANIA. 
Autum'nal Plu'mage.—The full dress of the autumn. In most birds it remains 
essentially unchanged till the spring moult. In many species the young pos¬ 
sess a peculiar autumnal plumage (assumed by the first moult) which differs 
not only from their first livery but also from that of adults at the same season. 
In such, the adult or mature plumage may be completely assumed at the next 
moult, or it may be gradually acquired by successive moults, as in the case 
of many Orioles ( Icteridce ), Tanagers and other bright-colored Passerine 
grdups. 
A'vis.—Plural aves. Bird. 
Av'ian Fauna, > 
Avi-fauna s The k* r( *-lif e of a particular country or locality. 
Ax'illa.—Armpit. 
Ax'illar. i 
Ax'illary. \ Pertaining to the armpit. 
Ax'illaries. ) The (generally) soft and lengthened feathers growing from the arm. 
Ax'illares. $ pit. 
B. 
Back.—Dorsum. In descriptive ornithology, usually includes the scapulars and 
interscapulars, but should properly be restricted to the latter alone. 
Back of Neck.—Cervical region. Includes Nucha and Cervix (which see). Equiv¬ 
alent to hind-neck. 
Band.—Any crosswise color-mark, transverse to the long axis of the body. A 
broad band is usually called a zone. 
Band ed or Barred.—Marked with bands or bars. 
Barb.—Any one of the laminae composing the web of a feather. 
Barb ed.-Furnished with barbs ; bearded. 
Base.'—Bottom ; root; origin. 
Ba sal.—Pertaining to the base. 
Bay.—A very rich dark reddish chestnut. 
Beak.—Bill. 
Bel'ly.—See abdomen. 
Belt.—A broad band of color across the breast or belly. (Distinguished from zone 
in that the latter may cross the wings or tail.) 
Binomial. 
Bino'minal 
Belt'ed.—Marked with a broad band of color across the lower part of the body, as 
in the Belted Kingfisher. — 
Bend of Wing.— Angle or prominence formed at the carpus (wrist-joint), in the 
folded wing. 
Bev'y.—A flock of quails or partridges. 
Bi -colored.—Two-colored. 
( Two-nained, or, more properly named by two terms. The binomi¬ 
nal system of nomenclature , instituted in 1758 by Linnaeus, and 
^ adopted by zoologists and botanists, promulgates the use of two 
terms as the name of each species—the first generic, the second 
specific. 
Boot.—In birds, the tarsal envelope, when entire. 
Boot'ed.—A booted tarsus has the usual scales fused so as to form a continuous or 
uninterrupted covering. The tarsus of the smaller thrushes and American 
Robin ( Merula migratoria ) well illustrate this character. 
Boreal.—Northern. 
Breast.—Anterior portion of lower part of trunk, between jugulum and abdomen ; 
properly, the region overlying and containing the breast-bone, but generally 
restricted to the more forward swelling portion of each region. 
Bris'tle.—Small, stiff, hair-like feather, especially about the mouth or eyes, but 
sometimes on other portions of the plumage also. 
Buff or Buffy.—Pale brownish-yellow ; color of yellow buckskin. 
