Possible Clues:

• Bird Cockney might misidentify from sound
• Perhaps a British flier
• North Sea diving bird
• Northern sea-bird with short narrow wings
• Northern sea bird with short narrow wings
• There might be a clumsy word, by the sound of it, for this bird
• A seabird from Milwaukee
• Black/white diver
• Black/white northern diver
• Puffin's kin