Possible Clues:

• Dog bowled over powerful bird
• Cut the head off what has short legs to give it wings
• Dog
• Blackbird torn apart by hound
• Black bird caught by a dog
• HMS - was Darwin's ship; hunting dog
• Cut off its head and it won't have short legs but will have long wings
• Snoopy, for example
• In spite of its short legs, it can fly without its head
• Short in the leg and long in the wing at last