ret Marks (or Stress Marks, Hunger Traces, etc)
Feathers reflect a bird's nutrition and general condition. If a bird is starving or has an imbalanced diet when she is producing new feathers, these feathers can have deformities called stress marks or hunger traces appearing as a line across the feather. These are weak points of the feathers.
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Kestrel with stress marks on her feathers.
Photo courtesy of Marra Apgar. |
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Kestrel with stress marks on her feathers.
Photo courtesy of Steve Huy. © J. Steven Huy 2006 |