treatise on the feathers of birds
• (n.) The study or description of the arrangement of feathers, or of the pterylae, of birds.
<ornithology> The study or description of the arrangement of feathers, or of the pterylae, of birds. ... (06 Mar 1998) ... 
Pter`y·log'ra·phy noun [ Pteryla + -graphy .] (Zoology) The study or description of the arrangement of feathers, or of the pterylæ, of birds. 
pterylography Related 'writing' word units: glypto-; gram-; scrib-, script-.