Q. Can dog (or cat) fur be used for nesting material for the birds?
A. Some birds use animal fur they find in nature to line their nests. It provides a soft surface for the nestlings as well as acting as an insulator from cold and wet.
You can help those birds by providing fur from your dog or cat. By doing so, you might help their nesting success as they conserve energy by taking advantage of an easy source of animal fur.
However, you should not use any type of animal fur that has been exposed to flea or tick treatments.