Images made through a microscope. All subject types.
Is this from the iridescent 'eye' of the feather?
Yes, in and around the "eye". Peacock feathers are an excellent example of "structural color". Instead of pigments, the color is caused by microscopic surface "nanostructures" that cause wave interference with visible light. Very much like seen in certain beetles and in the wing scales of certain butterflies and moths. The actual structures are extremely small and can only be visually studied with electron microscopes.The strands appear iridescent, are they?
There is some interesting light physics going on... here a a couple of references:
http://jeb.biologists.org/content/209/4 ... l.pdf+html
For photography the physical appearance looks very "metallic". It's best to carefully check three color histograms to insure exposures that don't completely "blow out" one of the RGB channels.