Hoopoe Small 160×320 Medium 319×640 Large 511×1024 Download TIFF Original 1198×2400 | (251.2 KB) Description "Diagram showing the tracts where the principal growth of feathers occurs (Upupa epops). The dotted areas are the pteryla." -Galloway, 1915 Keywords bird feather growth, feather tracts, hoopoe bird, hoopoe feathers, pteryla, Upupa epops Galleries Birds: H-I Source: Thomas Walton Galloway Textbook of Zoology (Philadelphia, PA: P. Blakiston's Son & Co., 1915)
