Definitions of whistler:

• noun:   makes a loud high sound
• noun:   United States painter (1834-1903)
• noun:   Australian and southeastern Asian birds with a melodious whistling call
• noun:   large-headed swift-flying diving duck of arctic regions
• noun:   large North American mountain marmot
• name:  A surname (rare: 1 in 100000 families; popularity rank in the U.S.: #17490)