Feathers are a unique characteristic of all birds and, like hair, are also composed of keratin, a sulfur-rich fibrous protein. Elements and metals in the blood readily bind to the keratin as the feather grows and thereby provide dietary and metal exposure information along the length of the main shaft, or rachis. Why does this matter? The feather can:
- reveal changes in metal exposure as it relates to migration (local versus global exposure);
- characterize how changes in water quality and aquatic food webs are transferred to aquatic predatory birds, such as eagles and osprey; and,
- replace the need for invasive tissue or blood sampling of birds or chicks.
Feathers can characterize recent (root) metal exposure, and "lasering" along the rachis to the tip allows us to actually go back in time to temporally characterize previous exposure.