Knock Knock (1940)

Andy Panda asks Pop if you can really catch a bird by putting salt on its tail. Pop tells Andy not to bother him only to hear a knocking at the door. The "knocking" is really coming from a woodpecker pecking against their roof. Pop sets out to trap the bird but is no match for its screwiness. He uses a wind-up explosive decoy that the bird falls for but when it explodes, he just feels "betrayed!" After giving Pop a wild ride through the sky, Andy pours salt on his tail and traps it! Two ambulance attendants come to take the bird away but they too are just as looney!

The movie Knock Knock, released in 1940, features 1 song from the woodpecker by pecking on the roof.