Installing a bird nesting box in your yard or garden can provide wonderful opportunities to observe nesting birds up close. However, simply installing an empty box may not be enough to attract feathered tenants. Properly furnishing a nest box with appropriate materials can make all the difference in turning your birdhouse into a coveted residence.
Why Add Materials to a Nest Box?
Birds have very specific requirements when selecting a nest site. They need a safe, warm, and comfortable environment to raise their young. An empty wooden box alone often does not meet all these criteria. Birds may reject unlined nest boxes for the following reasons:
- The bare wood offers no insulation or warmth.
- The smooth surfaces make attachment of nests difficult.
- Ledges or corners could allow eggs to roll out of the nest.
- Parasites or predators may be able to access eggs or chicks.
Furnishing the interior of a nest box with appropriate materials can help create an attractive, functional nesting site that addresses these concerns. The materials provided allow birds to shape the interior to their preferences.
What are Good Nest Box Materials?
The best materials to put in nest boxes mimic the nesting sites that specific species use in their natural environment. These materials should be introduced in appropriate amounts and depths to form a sturdy base for birds to build upon.
Wood Shavings
Spreading 2-4 inches of non-aromatic wood shavings across the bottom of the box provides an excellent starter base. The shavings help insulate the interior and soak up moisture. Their texture grabs onto nesting materials woven throughout. Wood shavings are attractive to many species, including:
- Chickadees
- Nuthatches
- Titmouse
- Wrens
Pine Straw
Pine straw is perfect for mimicking the tree cavity nest sites used by some birds. Place 3-5 inches of straw across the floor of the nest box. Species that appreciate a thick pine straw base include:
- Woodpeckers
- Bluebirds
- Chickadees
- Nuthatches
- Titmouse
Grass
Drying grasses make excellent nesting materials that birds will weave into their nests. Add a few bundles of grass stems or sow a handful of quick-growing seeds like millet or oats. Species that regularly line their nests with grasses include:
- Chipping Sparrows
- Phoebes
- Robins
- Wrens
- Bluebirds
Moss
Cushiony moss mimics desirable nest sites in damp, wooded areas. Use a 2-3 inch base layer of mosses for species like:
- Chickadees
- Nuthatches
- Titmouse
Feathers
Many birds line their nests with soft feathers. Add a few feathers to your next box – just avoid feathers from any non-native or wild birds. Species that appreciate feathers include:
- Chickadees
- Titmouse
- Tree Swallows
- House Wrens
Pet Fur
Gather pet hair from brushes and add a bit to nest boxes. The fur helps provide soft, warm lining for nests. Birds that may use pet fur include:
- Chickadees
- Titmouse
- Finches
- Flycatchers
Dryer Lint
Plain white cotton lint from the dryer makes excellent soft nesting material. Just avoid lint with any artificial fabrics or chemicals. Use sparingly for species like:
- Chickadees
- Nuthatches
- Titmouse
- Wrens
What Not to Put in Nest Boxes
Some materials may actually discourage birds from using your nest box. Avoid the following:
- Materials from non-native or wild birds – to avoid diseases
- Loose synthetic fibers, fabrics, or lint
- Strong odors from chemicals, tobacco, moth balls
- Shredded paper
- Hay or straw (can harbor mites or mold)
- Sawdust (can irritate avian respiratory systems)
It is also important not to overstuff a nest box. Allow the birds to shape and build to their preferences. Too much pre-existing material may interfere with their natural behaviors and instincts.
When to Add Nesting Materials
The best time to add nesting materials to your boxes is late winter, just before breeding season gets underway. This timing allows birds to incorporate the materials into early nest building. You can continue to add small amounts of fresh grasses, feathers, and fibers through early spring as birds start prospecting nest sites.
Once a box is occupied with an active nest, resist adding more materials. Parents may abandon the nest if significant changes occur mid-cycle. Allow the birds to complete the nesting process undisturbed until the young have fully fledged in mid-summer.
Make sure to clean out old materials from used nests after the breeding season ends. Freshen up the boxes with new nesting materials the following late winter to start the cycle again.
Monitoring Nest Box Use
Keep an eye on your nest boxes to see if your furnishing efforts are a success. Look for the following signs that birds have accepted the box:
- Nesting materials moved around
- Nest structure taking shape
- Eggs in nest
- Parent birds entering/exiting
- Begging calls from nestlings
If a box remains unused, consider relocating it to a better area or using different nesting materials next season.
Conclusion
Providing the right nesting materials in your birdhouses and boxes is an important step to attracting feathered tenants. Invest some time to research which species you hope to attract, and tailor the materials to their natural preferences. With some planning and trial and error, you can transform an ordinary wooden box into a coveted nursery for your backyard birds.