Chickadees excavated and nested in standing deadwood at the edge of my
garden in 1998. That short snag, about seven feet high and maybe eight
inches in diameter fell down that winter. Last spring I went into the
woods and retrieved a similar sized piece of dead punky alder that was
down on the ground and wired it to a fencepost in a setting similiar to
where the birds previously nested, an area somewhat open, near a perch,
adjacent to cover. A pair of Blackcaps excavated a cavity and nested
there. The entrance tunnel that led to the nesting cavity was quite
narrow and would prevent entry by House Sparrows (passer domesticus) in
my opinion.

Stan Kostka Arlington Wa