Birds often use nesting material that is offered to them to build their nests and insulate roosting cavities in the winter. For a full list of materials that you can provide, check out Providing Nest Material For Birds: Dos & Don’ts.
Keep in mind, that some material, such as dryer lint, may seem desirable, but can actually be dangerous to birds. Pet hair should only be offered from pets that have not received flea or tick treatments. Soft fluffy pet fur taken from the undercoat of a pet, or very fine fur like pet rabbit fur, may soak up water, so that too should be avoided.
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