Birds put an incredible amount of effort into constructing nests or excavating nest cavities, but will adding nesting material to bird houses help encourage birds to take a break and use a convenient house, or will it make the houses less attractive to prospective tenants?
Birds and Nesting Material
Birds use a wide variety of nesting material, from grasses, mosses and twigs to animal fur, bits of string, mosses, mud, spider silk and more. Some birds will even use more unique materials such as strips of plastic bags, snakeskin or aluminum foil, but despite the variety of materials, they can be picky about what they choose to construct their nests with and how different materials are interwoven. Adding nesting material to bird houses is not usually a good idea, and the birds that want to use the house may simply remove any well-meaning additions before they begin nest construction – making more work for them and making a bird house with included nesting material less attractive overall.
Nesting Material to Add to Bird Houses
While most birds are picky and will simply remove or rearrange any added nesting material, birds that do not build elaborate nests may appreciate a thin layer of coarse sawdust or small wood chips added to a bird house or nesting box. Birds that would naturally chip out a nesting cavity – woodpeckers – are not put off by sawdust or wood chips in the bird house, and the nesting material can help insulate and cushion any resulting eggs. Owls are also amenable to this nesting material, because they are used to reusing old woodpecker nesting cavities. If a bird house is specifically meant for woodpeckers or owls, a layer of sawdust or fine wood chips up to one inch thick can be added to the house, but be sure the material is coarse enough that it cannot cause breathing difficulties or a smothering hazard for young hatchlings.
Other Nesting Material Options
Because most birds do not appreciate nesting material added to bird houses, backyard birders need to find other ways to attract birds with nesting material without making the actual nesting sites less promising. Options include:
- A small puddle nearby for mud and gravel.
- A pile of pine needles, small twigs and grass clippings.
- A mesh suet cage or net filled with cotton fibers, bits of string or fur.
Many wild bird stores and online retailers offer nesting materials in balls, cages or other attractive packets that can be hung out for birds to pick from. Hanging or setting these and other nesting materials near promising nesting sites, including bird houses, can encourage birds to build their nests nearby, and birders can watch the birds claim nesting material to learn where nests are located, even if the bird house isn't a favorite location.
A Note About Dryer Lint
While the soft fluff from a dryer may seem to be perfect to keep young birds warm and safe, it is not recommended as a nesting material. The chemicals in clothing dyes and laundry detergents can be toxic to birds, and the lint itself can crumble and collapse when it gets wet or as growing birds exert stress on the nest. A broken nest offers little protection for birds, and hatchlings can tumble out of a weak nest prematurely, exposing them to injury, cold and threats from predators.
Cleaning Houses After the Nesting Season
Regardless of whether or not you have added nesting material to bird houses, the houses should be cleaned out after every brood of young birds has left the nest and before a new brood is begun if birds reuse the house in the same season. Old nesting material can be contaminated with feces, mites, discarded food, eggshells, insects and other hazards that can be dangerous for the next set of hatchlings and brooding adults, and it is best to discard all the material carefully. New sawdust or wood chips can be added to woodpecker houses after the house is cleaned, but if new eggs have already been laid, it can be illegal to disrupt or disturb them.
Adding nesting material to bird houses is not necessary for most bird species, but a layer of sawdust or wood chips can be helpful for woodpecker bird houses or owl nesting boxes. Added to the appropriate bird houses, nesting material can be helpful to cushion eggs and encourage birds to continue raising their families in your yard, but care must always be taken to offer only appropriate nesting material in appropriate ways, and to keep bird houses cleaned out after each brood to safeguard the next generation.
Photo – Sawdust and Wood Chips © Horia Varlan