Sonoma County Nest Box Dimensions Chart

Sonoma County Nest Box Dimensions Chart

Note: Each species has its own unique nesting criteria, and many factors determine whether or not a bird will use a box. However, it is important to construct the boxes according to the chart dimensions. The entrance hole diameter is critical to a successful nest box.

* Denotes species that reside year-round in Sonoma County.
 

Native Bird Species
Entrance
Hole Diameter (in.)
Floor Size (in.)
Box Height (in.)
Entrance Above
Floor (in.)
Height Above Ground (ft.)
*Barn Owl
6
16 x 20
16
4
15-30
*Northern Sawwhet Owl
2
7 x 7
12
8-10
10-20
*Screech Owl
3
8x8
18
9-12
5-30
*Wood Duck
3x4 (oval)
12x12
24
12-16
5-40
*Downy
Woodpecker
1
4x4
12
6-8
5-20
*Hairy
Woodpecker
1
6x6
14
6-8
6-20
*Pileated
Woodpecker
4
12x12
24
12-16
15-25
*Northern
Flicker
2
7x7
18
14-16
6-20
*Chestnut-Backed Chicadee
1
4x4
12
6-8
5-15
*Oak Titmouse
1
4x4
12
6-8
5-15
*White-Breasted
Nuthatch
1
4x4
12
6-8
4-20
*Red-Breasted Nuthatch
1
4x4
12
6-8
4-20
*Pigmy Nuthatch
1
4x4
12
6-8
4-20
*Bewick’s Wren
1
4x4
12
6-8
6-10
American Kestrel
3
9x8
21
9-10
15-30
Ash-Throated Flycatcher
1
6x6
12
6-8
6-20
Tree Swallow
1
5x5
10
2-5
3-15
Violet-Green Swallow
1
5x5
10
2-5
3-15
Purple Martin
2
6x6
6
1
12-25
House Wren
1
4x4
12
2-6
6-10
Western Bluebird
1 9/16
5x5
12
6-7
5-10