North American songbird (seen over the White Cliffs of Dover?) (8)
I believe the answer is:
bluebird
(Other definitions for bluebird that I've seen before include "symbol of happiness" , "Racing car" , "North American songbird (once seen over Dover?)" , "American member of thrush family (seen over Dover?)" , "Name of the cars and boats in which Malcolm and Donald Campbell set land and water speed records" .)