NC State Extension Publications

Cavity Nesters Need Homes

In a perfect world there would be plenty of cavities and dead trees in forests for all the wildlife species that require them. However, young plantations and many natural timber stands often lack adequate cavities.

There are two ways to remedy this situation:

  1. Provide artificial nest boxes (Figure 1)
  2. Increase the number of natural cavities

This publication will focus on constructing and placing artificial nest boxes. Please consult WWW-14, Snags and Downed Logs, for details on increasing the number of natural cavities on your forest land.

Figure 1. Nest box.

Figure 1. Nest box.


Woodland cavity nesters.
Barn owl Flicker
Pileated woodpecker Red-bellied woodpecker
Red-headed woodpecker Downy woodpecker
Gray squirrel Flying squirrel
Wood duck Raccoon

Use nest boxes when:

  • Few natural cavities exist
  • Competition for natural cavities is great
  • Target species populations are low
  • Rapid habitat improvement is desired

Dimensions for woodland nest boxes.
Species Hole Diameter (inches) Cavity Depth (inches) Floor Cavity (inches) Entrance Hole Height (inches) Mounting Height (feet)
Flying squirrel 3 15 - 18 8 x 8 9 - 12 20 - 30
Gray squirrel 3 20 9 x 9 16 20 - 25
Wood duck 3 x 4 oval 24 9 x 9 16 20 - 25
Flicker 2.5 16 - 18 7 x 7 14 x 16 6 - 20
Raccoon 5 x 9 oval 24 10 x 10 19 10 - 20
Barn owl 6 15 - 18 10 x 18 4 20 - 30+
Downy woodpecker 1.25 10 4 x 4 6 - 7 6 - 20
Red-headed woodpecker 2 12 6 x 6 7 - 8 6 - 20

Tips for Successful Nest Boxes

  • Mount nest boxes in suitable habitat for selected species.
  • Construct nest boxes using decay and weather resistant materials such as cypress, cedar, heart pine and oak.
  • Place nest boxes in most critical (plantations and young timber stands) areas first, then expand efforts to additional areas as time and money allow.
  • Use predator guards whenever possible and practical.
  • Consult wildlife biologists for species requirements of species not listed in this publication.

Habitats of woodland cavity nesters.
Species Habitat
Gray and flying squirrels Young to mature woodlands
Wood duck Mature woodlands adjacent to flooded woodlands, ponds, or open marshland
Flicker Open areas with perennial forbs and grasses
Raccoon Riparian regions and lands adjacent to wetlands
Barn owl Open pasture and agricultural fields
Downy woodpecker Woodlots, parks, and gardens
Red-headed woodpecker Open country, farms, and park-like woodlands

Maintenance Tips

  • Remove old nesting materials and repair or remount nesting structures annually following fledging period.
  • Check ventilation and drainage holes for proper functioning during annual cleaning.
  • Adjust mounting bolts and wires annually or as needed to account for tree growth or wear and tear.


Associate Director and State Program Leader, ANR and CRD
Extension Forestry Specialist
Forestry & Environmental Resources

Publication date: Jan. 1, 1994

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