How to make an animated Dark-eyed Junco decoy

Haans Petruschke has been studying Ohio’s disjunct Dark-eyed Junco breeding population since 2017. As part of the project, he fashioned a Dark-eyed Junco decoy out of basswood to draw birds to a banding site. Here’s how he did it:

Making Doug started with two sketches of profile and dorsal views of a junco in the posture of a displaying male. The sketches were then glued to a block of basswood, and a scroll saw cut outside the lines. Next was carving with knives and chisels. When the shape was good, details like the eye and auricular area were added. The beak was taken to its final size and shaped last. Then a bastard cut file was used to smooth and add texture. The holes for the legs were drilled. 

The paint is artist’s acrylic and mixed to get the desired colors. The legs are made from clothes hanger wire and are held in place with cyanoacrylate glue and flats hammered on the wire.

The animation mechanism was made using a small DC gear motor controlled by an Arduino Nano microcontroller. A motor control module with an X bridge was used to achieve forward and reverse. This required designing an electronic circuit which was tested on a breadboard. A circuit diagram was made, then then the whole thing was assembled on a circuit board.  The animation is controlled using an Arduino sketch, computer code written in C language which has syntax requirements specific to the Arduino controller. The control board, motor, 9-volt cell, and power switch were fitted into a small project box which has seals to keep out rain and moisture. A limit switch is attached to the outside of the box to provide a reference limit so Doug does not process or change orientation as he moves. 

The mechanical plate and other bits were shop-made using mostly brass and aluminum. Parts are held together with silver solder and small screws. The control box is attached to a stake that was shop fabricated out of stainless steel sheet. The post is hardwood and has a spike made out of rebar on the bottom to anchor in the ground. This also has a section bent 90 degrees so you can use your foot or boot to get it into the ground. It is held on with hose clamps. The whole assembly including the box with the control and motor is painted with spray lacquer to achieve a camouflage effect. There is a switch on the outside of the box used to turn on the animation. Once activated Doug goes to a home position, then delays for a couple of minutes before starting his animated movements. The post has a hook for a Bluetooth speaker used to play the song and other vocalizations. This is the only aspect remotely controlled.

Here is a video of Doug in action:

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