|Additionally, a U-shaped clip made out
of the same wire as the trigger works well to hold the portable
trap board in position inside of a top opening box, The
span of the clip equals the combined thickness of the box front
and the portable trap boards.
For side opening boxes, a wood screw driven through the front
of the box will engage the trap board to hold it in position.
To install the trip rod, measure down four inches and draw a
line. This is where the trip rod is attached with the two
insulated staples. The rod must be bent to shape before
Steps to follow: Attach the trap plate, then the stop screw,
followed by the trip rod.
After completing the portable trap version, be sure to turn
it over and file off the points of the staples and screws flush
that may have penetrated the board to the other side.
Remember, this is a two dimensional drawing that does not
show the three dimensional shape of the trip rod. You are
forming the trip rod to be contacted by the sparrow's body when
the bird drops into the lower box area.
When bluebirds are using the box and the is "at
rest", the lower portion of the trip rod is flat against
the box front, while the upper portion will not interfere with
the coming and going of the bluebird pair.