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 

 ot many Orioles (Icteridce), Tanagers and other bright-colored Passerine 

 groups. 



A'vis. Plural aves. Bird. 



Av'ian Fauna, i 



Avi-fauna. \ The bird-life of a particular country or locality. 



Ax' ilia. Armpit. 



Ax'illar. > 



Ax'illary. \ Pertainin g to the armpit 



Ax'illaries. ) The (generally) soft and lengthened feathers growing from the arm. 



Ax'illarea 5 pit 



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.) 



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-named, or, more properly named by two terms. The binomi- 

 nal system of nomenclature, instituted in 1758 by Linnaeus, and 

 J 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. 



Bo'real. 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. 



