Microscopic samples were made from the plumulaceous (downy) region of the feathers according to methods described in Dove and Koch (2010) and viewed using a Leica compound light microscope (10X-400X, Leica Microsystems CMS GmbH, Wetzlar, Germany).
Because the feathers were white or black in color and did not have any observable pattern or diagnostic markings, we examined the microscopic structures in the plumulaceous (downy) region in an attempt to assign the feathers to an order or family of birds.
We used only the spectrum exhibiting the greatest difference in reflectance between 800 and 456 nm (the peak of absorption) of several (>15) readings of each feather analyzed for calculations, because the spectra were degraded by inclusion of the grayish plumulaceous
bases of feathers which varied with feather positioning.
The feather identification technique involved examining the variation in the microscopic characters of the plumulaceous
(downy) barbs and comparison of whole feathers or large pieces of feathers to museum study skins stored in the Division of Birds, National Museum of Natural History.