Possible Clues:

• Sounds as if a brace of this can be only one bird
• By the sound of it, one brace can be one bird
• Bird with large beak
• Bird flying out over chimney pot
• Thus, by the sound of it, a brace can be only one bird
• Bird with colourful bill
• Also heard before prison, getting bird
• Large bird
• Sounds as if a brace of them is able to make one of Big Bill
• Starting out, can make it for Big Bill