NC State Extension Publications

Cavity Nesters Need Homes

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In a perfect world there would be plenty of dead trees (aka, snags) loaded with cavities in forests for all the wildlife species that require them. However, urban and suburban landscapes, young pine plantations, and many other forest stands often lack adequate snags and associated 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, Snags and Downed Logs, for details on increasing the number of natural cavities on your forest land. Please consult, Building Songbird Boxes, for details specifically related to songbird nest boxes.

It is critical that nest boxes be constructed and placed in a manner appropriate for the target wildlife species. This publication provides a brief overview of the information that can help you initiate efforts to increase cavity availability for focal cavity users on your property.

Photo of volunteers with new wood boxes

Volunteers stand with new wood boxes ready for installation.

Steve Hillebrand, USFWS  CC BY - 4.0

Figure 1. Nest box.

Figure 1. Wood duck nest box.

Woodland Cavity Nesters

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Woodland cavity nesters.

Barn owl

Northern flicker

Pileated woodpecker

Red-bellied woodpecker

Red-headed woodpecker

Downy woodpecker

Gray squirrel

Southern 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 Size (inches)

Entrance Hole Height (inches)

Mounting Height (feet)

Southern flying squirrel

1 ½

12

7 x 7

10

10 - 26

Gray squirrel

3

18

8 x 8

14

18 – 30

Wood duck

3 ½ x 4 ½ oval

23 ½

7 ¾ x 9 ¼

14

20 – 25

Northern flicker

2 ½

24

7 x 7

14 x 16

6 – 12

Raccoon

5 x 9 oval

24

11 ½ x 11 ½

19

10 – 20

Barn owl

3 ¾ x 4 ½

16

11 x 22 ¾

4

8-25

Downy woodpecker

1 ¼

8 - 10

4 x 4

6 - 8

5 - 15

Red-headed woodpecker

2

12 - 15

6 x 6

9 - 12

10 – 20


Tips for Successful Nest Boxes

  • Mount nest boxes in areas appropriate for selected species.
  • Construct nest boxes using decay and weather resistant materials such as cypress, cedar, heart pine, and oak.
  • Avoid using painted or treated wood.
  • 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.
  • Fill nest boxes meant for woodpeckers with wood shavings or sawdust, so the adults can complete the excavation process (digging down through the sawdust) that is important for pair bonding.
  • Consult wildlife biologists for habitat requirements of species not listed in this publication.

Photo of Carolina chickdee in a nest box

Carolina chickadee in nest box (note the predator guard).

Liessa Bowen  CC BY-NC - 4.0

Photo of brown-headed nuthatch using a nest box

Brown-headed nuthatch using a nest box.

Liessa Bowen  CC BY-NC - 4.0

Habitats and Maintenance Tips

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Habitats of woodland cavity nesters.

Species

Habitat

Gray and flying squirrels

Young to mature woodlands

Wood duck

Mature woodlands adjacent to forested wetlands, ponds, or marsh

Northern flicker

Sparsely wooded areas, field edges

Raccoon

Forested wetlands, streamside forest

Barn owl

Areas of extensive grassland, pasture, or agricultural fields

Downy woodpecker

Suburbs, forest, urban woodlots

Red-headed woodpecker

Park-like woodlands and golf courses


Maintenance Tips

  • Remove old nesting materials and repair or remount nesting structures annually after young have left the nest.
  • 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.

Authors

Extension Professor
Forestry & Environmental Resources
Wildlife Biologist
Professor (Wildlife)
Forestry & Environmental Resources

Publication date: May 24, 2019
Revised: June 24, 2019

North Carolina State University and North Carolina A&T State University commit themselves to positive action to secure equal opportunity regardless of race, color, creed, national origin, religion, sex, age, veteran status or disability. In addition, the two Universities welcome all persons without regard to sexual orientation.

North Carolina State University and North Carolina A&T State University commit themselves to positive action to secure equal opportunity regardless of race, color, creed, national origin, religion, sex, age, veteran status or disability. In addition, the two Universities welcome all persons without regard to sexual orientation.