Question 1

Why is there no perch under the entrance?

Accepted Answer

Audubon, Cornell Lab of Ornithology, and NestWatch all recommend omitting the perch. Cavity-nesting birds grip the edge of the entrance directly and don't need one. A perch mostly helps predators like squirrels, jays, and house sparrows reach the hole and harass the nest. Leaving it off is the correct design.

Question 2

Where do the species dimensions come from?

Accepted Answer

Floor sizes, interior heights, entrance-hole diameters, and entrance-height-above-floor follow the NestWatch 'Right Bird, Right House' chart — the same specs Audubon and Cornell Lab publish. Each species has a specific entrance diameter that admits the target bird but excludes predators and competitors.

Question 3

What material should I use?

Accepted Answer

Untreated cedar, pine, or exterior plywood works well. Avoid pressure-treated lumber (chemicals can harm birds and chicks). The default thickness is 12 mm (about 1/2 in) which is the Audubon recommendation for weather resistance and predator deterrence. The smallest practical thickness is around 9 mm.

Question 4

Why does the floor have small holes?

Accepted Answer

Four corner drainage holes (about 6 mm) let any wind-driven rain escape so the nest stays dry. They also improve airflow on hot days. You can disable them under Advanced — Floor, but Audubon and NestWatch both recommend including them.

Question 5

How do I clean it out?

Accepted Answer

The roof is the largest removable panel — leave it press-fit (no glue) and lift it off in late winter to clean out old nesting material before the next breeding season. Audubon recommends annual cleanout.