On Wed, 9 Aug 1995, Susan Collicott wrote:

> This winter I'm going to make a number of birdhouses, and would like to take
> a look at some how-to books.

Hi Susan,

Because of the abundance and aggressive nature of House Sparrows in
the city these two models of restrictive entrance holes below are very
useful in keeping them out.

Violet-green SWALLOW HOUSE - Urbanites

/-------------------------------/|
/ / |
/ / |
/ /| |
/______________________________/ | |
| ___ | | 6"
| ( ___ ) | |
| | |
| | |
| | |
| | /
| | / 4"
|-------------------------------|/
8"

The opening is an oblong 7/8" high by 2" wide. This can be made
by drilling two 7/8" holes and using a keyhole saw to cut out the extra
wood in the middle. The bottom of the entrance should be 3" from the
bottom of the house. This entrance shape keeps out House Sparrows while
allowing Violet-green Swallows in. The design of this house is by Hubert
Prescott, taken from a sheet published by the Black Hills Audubon Society.

An alternative opening is an elongated diamond 7/8" high and 3
1/2" wide designed by Gene Derig of Anacortes, WA. Besides swallows I had
a pair of Black-capped Chicadees accept the diamond opening version of
this house, even though it was suspended under the eave of the roof!

Dan Victor
Seattle
dvictor at u.washington.edu