1. plural of bluebill; ducks with blue-colored bills, especially scaup ducks
Usage: ornithology

Examples

• The hunters spotted a flock of bluebills on the lake.
• Bluebills are common waterfowl in North American wetlands.
• The bluebills dove underwater to feed on aquatic plants.
• During migration, thousands of bluebills gather in coastal bays.
• Wildlife photographers often seek out bluebills for their distinctive appearance.
• The bluebills’ diving behavior makes them excellent swimmers.