Bird House or Nest Box Dimensions

To see a basic Bird house plan to apply these dimensions to, click here to see a Bird House Plan.  

When deciding on the dimensions for your birdhouse consider what that bird might use in its natural environment.  Primary cavity nesters such as woodpeckers, chickadees, and nuthatches control the size of the hole by using their bills to chisel a hole in a tree.  Other cavity nesting birds called secondary nesters use cavities that are either already there or were created by primary cavity nesters.  Secondary nesters are are birds such as bluebirds, swallows, and titmice.  For many birds you want a hole large enough that they can easily come in and out, but small enough that it keeps out predators and birds like starlings which are very aggressive and will monopolize your bird house.  A hole 1 9/16 inches or smaller will usually keep starlings out.

The inside should accommodate the size of nest a particular species builds.  There should be enough distance from the hole so predators can not reach in, and get the babies, yet young birds will be able to look out, and be fed by the parents.

               Box      Box      Entrance   Entrance   Placement
               floor    height   height     diameter   height
 Bird          inches   inches   inches     inches     feet
 ===============================================================
 Bluebird      5x5      8-12     6-10       1-1/2      4-6
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 Chickadees    4x4      8-10     6-8        1-1/8      6-15
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 Flycatcher    6x6      8-12     6-10       1-3/4      5-15
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 Northern
 Flicker       7x7     16-18    14-16       2-1/2      6-20
 ---------------------------------------------------------------
 Nuthatches    4x4      8-10     6-8        1-1/4      5-15
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 Warbler       5x5        6      4-5        1-1/8      4-8
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 Purple
 Martin        6x6        6      1-2        2-1/4      6-20
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 Titmice       4x4     10-12     6-10       1-1/4      5-15
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 Tree and Violet-Green
 Swallows      5x5      6-8      4-6        1-1/2      5-15
 ---------------------------------------------------------------
 Downy
 Woodpecker    4x4      8-10     6-8        1-1/4      6-20
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 Hairy
 Woodpecker    6x6     12-15     9-12       1-1/2      8-20
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 Lewis's
 Woodpecker    7x7     16-18    14-16       2-1/2     12-20
 ---------------------------------------------------------------
 Pileated
 Woodpecker    8x8     16-24    12-20        3x4      15-25
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 Red-Headed
 Woodpecker    6x6     12-15     9-12         2       10-20
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 Yellow- bellied
 Sapsucker     5x5     12-15     9-12       1-1/2     10-20
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 House wrens   4x4      6-8      4-6        1-1/4      6-10
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 Barn Owls    10x18    15-18       4          6       12-18
  ---------------------------------------------------------------
 Screech Owls and
 Kestrel       8x8     12-15     9-12         3       10-30
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 Birds below use nesting shelves instead of nest box
 Swallow*      6x6        6      ---         ---       8-12
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 American
 Robin*        7x8        8      ---         ---       6-15
 --------------------------------------------------------------- 
 Phoebes*      6x6        6      ---         ---       8-12
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Here is a good selection of bird houses