Birdhouse Comparisons - Pros and Cons of Birdhouse Designs

Highlighted below are the advantages and disadvantages to some of the many birdhouses available for smaller songbirds. When wrens are nesting, an adult house wren needs to collect over 30 grams/day (wet mass) of insects to maintain itself and its nestlings during peak nestling food demands. This is extremely valuable in a home garden environment where many insect pests are targeted by house wrens.

With this in mind, these birdhouses are compared based on how well they would work as a birdhouse for wrens and other smaller songbirds such as chickadees, titmice and nuthatches.

Wooden Simple Box

Pros

Wood provides insulation in extreme cold and warm weather
Post (t-bar) makes it difficult for predators to reach the birdhouse

Cons

Screwdriver needed to clean
Bird nest disturbed to view interior of birdhouse
Difficult to mount and take down to clean
Interior dimensions are large and unfavourable for small songbirds
Large openings near roof provide too much ventilation for cool spring weather

Addional Comments

Mounted by metal bracket on T-bar
Most likely intended for swallows or larger birds

Wooden Asphalt Roof

Pros

Asphalt creates waterproof roof
Entrance hole cannot be made larger by predators with predator guard and extra plywood

Cons

Screwdriver needed to clean
Bird nest disturbed to view interior of birdhouse
Difficult to mount and take down to clean
Asphalt may heat up in summer heat

Addional Comments

Mounted with two screws in back wall above roof

Wooden Slanted Roof

Pros

Wood provides insulation in extreme cold and warm weather

Cons

Unable to clean out old nests
Dificult to mount
Hole too large for smaller songbirdse
Without the ability to clean the house out and the improper deminsions and hole size, this is more of a decorative birdhouse

Addional Comments

Mounted 1 m (3 feet) from ground is not ideal

Concrete with Metal Roof

Pros

Will not rot like wood
Entrance hole cannot be made larger by predators

Cons

Metal roof becomes hot in direct sun
Screwdriver needed to clean
Bird nest disturbed to view interior of birdhouse
Difficult to mount and take down to clean
May crack if dropped

Addional Comments

Mounted by wire from top of birdhouse to screw on tree

Composite Bluebird

Pros

Composite recycled plastic will not deteriorate over time
Entrance hole cannot be made larger by predators
Baffle below ensures squirrels are unable to climb to the house
Latch does not require screwdriver to clean

Cons

Plastic may not be completely non-toxic

Addional Comments

Size of hole and larger interior volume indicates birdhouse is intended for bluebirds

Cedar

Pros

Wood provides insulation in extreme cold and warm weather
Cedar is rot resistant and deters insects
Entrance hole size can be changed with different insert

Cons

The smell of cedar is overpowering for the birds
Difficult to mount
Plyers are needed to clean out old nests
Interior can not be viewed without disturbing the nest

Addional Comments

Mounted with one screw on the thin back board

Wooden Simple Box

Pros

Wood provides insulation in extreme cold and warm weather
Birdhouse has appropiate inner volume for wrens
Non-toxic finish
Ideal size for wrens

Cons

Single screw on lid must be removed to clean out nest
Difficult to mount and maintain

Addional Comments

Mounted with two screws to barn board siding of a shed

Wooden Asymmetrical

Pros

Wood provides insulation in extreme cold and warm weather

Cons

Birdhouse inner dimensions slightly too large
Difficult to open to clean nests
Paint may be toxic to birds

Addional Comments

Mounted with one screw on back board

Wooden Symmetrical

Painted birdhouse that is too small for birds

Pros

Wood provides insulation in extreme cold and warm weather

Cons

Birdhouse inner dimensions too small
Cannot be opened to clean nests
Entrance hole too large for internal dimensions
Paint may be toxic to birds

Addional Comments

Mounted with one screw on back board

Decorative Multi-compartment

Pros

Aesthetically pleasing

Cons

Difficult to near impossible to clean out nests
Interior volume in compartments too large
Hole size too large for purple martins
Paint may be toxic
Metal roof unfavourable heating up inside compartements

Addional Comments

Not mounted high enough for birds to occupy

Birdhouse Feature Summary

After researching many designs and reading many scientific journal articles it has become apparent that there are many flaws in current birdhouse models on the market for small songbirds such as chickadees and wrens. The aim is to provide birdhouses with as many favourable attributes as possible to give the birds a better chance, and make it easier for the care taker.

The table below shows attributes to look for if a birdhouse for chickadees, nuthatches, titmice and wrens desired for.

Feature	Favourable	Unfavourable
Body Material	Pine Spruce Composite Non-toxic hardwoods	Cedar Metal Pressure treated wood Squash
Roof Material	Pine Spruce Composite Non-toxic hardwoods	Metal Asphalt shingle 2 cm3/4" thickness
Preservative	Non-toxic waterproof urethane Tung oil Linseed oil	Paint Urethane
Drainage Holes	3+	< 3
Interior Volume	780-900 cm³	900+ cm³
Interior Depth	~10 cm4 "	> 10 cm> 4 "
Nest Clean-out	Bracket with removable lid	Hinged side Hinged roof Removable back panel Bottom board
Observation Method	Removal of lid Hinged roof	No observation method Pexiglass walls
Mounting Method	Removable bracket	Screws in back wall mounting birdhouse
Birdhouse Placement	Predator-free area	Within 5 m from bird feeder Hanging from branch
Placement Height	1.2-2 m 5-12' high	< 1.2 m high < 5' high

With these features in mind, we have come up with two birdhouse designs that addresses these strengths and limit these unfavourable weaknesses. Cranmer Earth Design hexagonal birdhouse and turned birdhouse (below) are functional, easy to maintain and are aesthetically pleasing.

While many of the birdhouses on the market are said to be the perfect demensions for these birds, only these two designs have the solution to easy nest removal.

Wooden Hexagonal

Pros

Entire birdhouse comes off bracket without screwdriver
Lid comes off easily to remove nest, clean or view without a screwdriver
Coated with non-toxic PolyWhey urethane
Interior volume is too small for squirrels to try to occupy but favourable for wrens

Cons

Pine will deteriorate faster than hardwoods

Addional Comments

Made in Canada
Learn more here

Turned Hardwood

Pros

Entire birdhouse comes off bracket without screwdriver
Lid comes off easily to remove nest, clean or view without a screwdriver
Oak hardwood
Coated with non-toxic PolyWhey urethane
Interior volume is too small for squirrels to try to occupy but favourable for wrens and red breasted nuthatches

Cons

Small interior may limit fledgling size for chickadees

Addional Comments

Made in Canada
Learn more here

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Wooden Simple Box

Wooden Asphalt Roof

Wooden Slanted Roof

Concrete with Metal Roof

Composite Bluebird

Cedar

Wooden Simple Box

Wooden Asymmetrical

Wooden Symmetrical

Decorative Multi-compartment

Birdhouse Feature Summary

Feature

Favourable

Unfavourable

Wooden Hexagonal

Turned Hardwood