Interesting B&W Stop-Motion Animated Short

I would love to know how they did this. For 1930 this is amazing special effects. The YouTube description is copied below.

Excerpt from a bizarre early stop-motion animation piece featuring Charley Bowers and a metal-eating bird. The creature devours junk from an auto scrapyard, then lays an egg that hatches and grows into a brand new car! Very impressive FX and way before CGI. Directed by Harold L. Muller.