The January weather here can be frightful, but our Bald Eagle winter residents don’t seem to mind; they’re built for it. Their skin is protected by feathers lined with down and their external parts have a winter-proof design that reduces the need for blood flow and has few nerves.
As with most fish-hunting raptors, their powerful lower legs and feet are scaled and consist mostly of tendons; there are no leg-covering feathers to get cold, wet, and bloody. Their toes are padded with Velcro®-like spicules to help keep slippery fish in place.
Their dig-and-rip beaks and their hold-and-kill claws are made primarily of insensitive keratin protein (think fingernails). See also the image in the first Comment space. (Brooklin, Maine)