Several weeks ago I had a male House Sparrow checking out my nesting
box. The sparrow managed to squeeze in even though the hole is only
31mm wide (just shy of 1 1/4"). Then he disappeared.
For the last few days a pair of Chestnut-backed Chickadees have been
excavating the box and looked like they may build a nest.

This morning, while the Chickadees were working away, about 3 pairs
of sparrows showed up and tried to get into the box again. The
chickadees were quite aggressive and were trying to chase the larger
sparrows away. At this point I had to leave for work but my husband
feels the sparrows won. They managed to chase away the chickadees
but seemed afraid to go back into the box again. One kept putting
his head through the hole but didn't enter.

I want to make the hole into an oval shape to keep the larger birds
out. Does anyone know whether I should make it an up and down oval
or a sideways oval? I did a search on the net and the dimensions
for chickadees was 1 1/8" (about 28.5mm) but it didn't say anything
about the shape of the hole. Someone told me to use popsicle
sticks to make the hole smaller, but they weren't sure how wide
it should be. My daughter has taken on the job of acquiring the popsicle
sticks ;-). TIA

Catherine
Catherine Fryer
Victoria, BC
cfryer at pacificcoast.net