Differences between Violet and Green Woodhoopoe mantle feathers.
Mark I. Cooper, Bryan Trevor Sewell, Mohamed A. Jaffer
...Taxonomic status of Namibian Violet Woodhoopoe Phoeniculus d. damarensis was determined by microscopic differences in violet and green mantle feathers. Outer iridophore diameters from Green Woodhoopoe P. p. purpureus barbules (0.22 ? 0.03 ?m, n = 244) were smaller than those from violet barbules (0.28 ? 0.04 ?m, n = 248) whereas the inner diameters were similar in both cases....