I bought some Bondo for another project and decided to give it a try.
First I made an armature of copper electric wire with the insolation removed. Added some smaller cooper wire used for hanging pictures.
Soldered it to strengthen it.
Then mixed up some Bondo. Interesting experiment, sets really fast and you have to work really fast. But just smear it over the wires and bam, you have a rough looking branch.
Smooth with regular sandpaper, it is fairly soft and sands easily. DO NOT breath the dust, use a mask.
Fairly impressed with my first attempt at using Bondo.
Sanded it and painted it with acrylic washes.
Remounted my poor little chickadee.