Figure 6
From: The Topobiology of Chemical Elements in Seabird Feathers
Examples of other visible periodic elements of a feather (A,B) with the invisible elemental periodicity observable within Zn distribution (C–E). Other examples of periodicity in feathers include the barbs and barbules themselves but also fault bars, alterations in the structure of the interlocking barbules caused by malnutrition or pathology, and growth bars, periodic pigment changes which often correlate diurnally with the time of feather growth. The periodicity observable in the Zn distribution does not correlate with any visible abnormalities, pigment changes, structural alterations or anatomy.
