#First complete quest "Get the ball back!" by talking to the boy outside Mr. Byrd's house. Then go through the Secret Byway near Shoten Temple to enter Byrd's yard the back way. Go inside and speak to Mr. Byrd.
#Complete quest "Bird Collection 1" from Mr. Byrd. (Befriend Snotsolong, Flumpy, and Peckpocket)
#Complete quest "Bird Collection 2" from Mr. Byrd. (Befriend Duchoo and Rockabelly)
#After beating the game you'll have access to Byrd's back room where Skreek is.