Ornithology at home

Building a Basic Birdbox

Section 1: Building a nest box
Section 2: Dimesions for common species
Section 3: References

One of the easiest ways to study birds is to observe them on the nest. One can go looking for nests in the wild and keep track of what happens from day to day or build nest sites and bring the observation to the comfort of a backyard. For more information on activities centered around nestboxes try the following sites:

Columbia Estuary Nestbox Project

Cornell Nest Box Network

Section 1: Building a nest box

Many species of birds depend on cavities for breeding. In the natural environment, woodpeckers, burrowing insects and natural decay provide cavities for nesting. Human activities including deforestation, pest management and the introduction of alien competitors like European Starlings and House Sparrows have affected the supply of nesting cavities. We can build artificial cavities to improve the availability of nesting space. This activity describes how you can build a simple, but effective birdbox, designed to attract bluebirds, chickadees, swallows and wrens.

Materials: one 1" x 6" x 5' cedar fencing

Cut out the pieces as described in the illustration to the left. There should be three 6" x 8" pieces for the front, back and roof; two 4" x 8" pieces for the sides and one 4" x 4" piece for the floor. Cedar fencing material is ideal for this, because it is resistant to decay and requires no finishing (though it may be finished if you'd like).

Assemble the pieces beginning with the bottom and one side. Attach the front and back, then the roof. The final side should be attached at the top with screws so that it can open and close for cleaning.

Use a 1.5" hole saw or Forstner bit to make the opening in the front of the box. It should be centered about 2.5" from the top of the box. Drill a small hole through the bottom front into the door side and secure it with a nail slightly smaller in diameter than the drill bit.

Section 2: Dimensions for common species

Commercially manufactured nest boxes are, more often than not, built took look nice rather than be functional, attractive nest cavities. Many species of birds are very particular about the size of the cavity and width of the entrance to the cavity. An entrance hole that is too small will not be used by any species. A large entrance does not provide protection from predators or aggressive competitors like starlings.

The following is a list of common northwestern species and the approximate dimensions of their preferred cavity nest. Any hole diameter greater than 2 inches will attract starlings and squirrels. An aggressive campaign of evictions may be required.

 Species               4code  interior     depth        entrance    placement

 Bluebird, Western     WEBL   5"x5"        8"           1.5"        5' to 10'

 Chickadee, Bl-cap     BCCH   4"x4"        8" to 10"    1.5"        5' to 15'

 Chickadee, Chst-bck   CBCH   4"x4"        8" to 10"    1.5"        5' to 15'

 Flycatcher, Ash-thr   ATFL   6"x6"        8" to 10"    2"          8' to 20'

 Kestrel, American     AMKE   8"x8"        12" to 15"   3"          10' to 30                                         

 Martin, Purple        PUMA   7"x12"       6"           1.25"x2.75" 15' to 20'

 Merganser, Hooded     HOME   10.5"x10.5"  24"          3"(ellip.)  10' to 25'

 Nuthatch, Pygmy       PYNU   4"x4"        8" to 10"    1.5"        5' to 15'

 Nuthatch, R-br        RBNU   4"x4"        8" to 10"    1.5"        5' to 15'

 Nuthatch, Wh-br       WBNU   4"x4"        8" to 10"    1.5"        5' to 15'

 Owl, Barn             BNOW   10"x18"      15" to 12"   6"          12' to 18'

 Owl, Saw-whet         SWOW   6"x6"        10" to 12"   2.5"        12' to 20

 Owl, W Screech        WSOW   8"x8"        10' to       3"          10' to 30'            

 Phoebe, Black         BLPH   6"x6"        8" to 10"    open side   8' to 20'

 Phoebe, Say's         SAPH   6"x6"        8" to 10"    open side   8' to 20'

 Swallow, Tree         TRES   5"x5"        6"           1.5"        10' to 15'    

 Swallow, Violet-gr    VGSW   5"x5"        6"           1.5"        10' to 15'

 Woodduck              WODU   10.5"x10.5"  24"          3"(ellip.)  10' to 25'

 Wren, Bewick's        BEWR   4"x4"        6" to 8"     1"          6' to 10'

References

The Complete Book of Birdhouse Construction for Woodworkers.

Ehrlich, Paul R., David S Dobkin & Darryl Wheye. 1988. The Birder's Handbook.
Simon & Schuster, Inc. New York

Gooders, John & Scott Weidensaul. 1990. The Practical Ornithologist. Simon & Schuster, Inc.
New York

Harrison, George H. 1988. The Backyard Bird Watcher. Simon & Schuster, Inc. New York

	Cut out the pieces as described in the illustration to the left. There should be three 6" x 8" pieces for the front, back and roof; two 4" x 8" pieces for the sides and one 4" x 4" piece for the floor. Cedar fencing material is ideal for this, because it is resistant to decay and requires no finishing (though it may be finished if you'd like).
Assemble the pieces beginning with the bottom and one side. Attach the front and back, then the roof. The final side should be attached at the top with screws so that it can open and close for cleaning.
	Use a 1.5" hole saw or Forstner bit to make the opening in the front of the box. It should be centered about 2.5" from the top of the box. Drill a small hole through the bottom front into the door side and secure it with a nail slightly smaller in diameter than the drill bit.