ClipArt ETC
"Diagram showing the tracts where the principal growth of feathers occurs (Upupa epops). The dotted areas are the pteryla." -Galloway, 1915

Hoopoe

"Diagram showing the tracts where the principal growth of feathers occurs (Upupa epops). The dotted…

"Pterylosis of Columba livia. A, ventral; B, dorsal. al. pt, alar pteryla or wing-tract; c. pt, cephalic pteryla or head-tract; cd. pt, caudal pteryla or tail-tract; cr. pt, crural pteryla; cr. apt, cervical apterium or neck-space; fm. pt, femoral pteryla; hu. pt, humeral pteryla; lat. apt, lateral apterium; sp. pt, spinal pteryla; v. apt, ventral apterium; v. pt, ventral pteryla." -Parker, 1900

Rock Pigeon Feather Tracts

"Pterylosis of Columba livia. A, ventral; B, dorsal. al. pt, alar pteryla or wing-tract; c. pt, cephalic…