Britannica Sources used in this answer

How do skimmers catch fish while flying over water?

Created from Britannica articles using AI. AI can make mistakes, so verify using Britannica articles.

Illustration of a crab plover (Dromas ardeola), showing a slender wading bird with long legs, a long pointed black bill, white head and underparts, and contrasting black wings and back. — Charadriiform Crab plover (Dromas ardeola)

Skimmers catch prey using a specialized feeding technique while flying over calm, shallow water. They fly with their long, bladelike lower mandible submerged, which acts as a knife cutting through the water's surface at speeds of up to 30 miles (48 km) per hour.12

When the lower mandible encounters a fish or crustacean, the bird’s head doubles under its body, and the upper mandible snaps down to clamp the prey shut. The skimmer then flies upward, swallowing the catch while still in the air or carrying it back to its nest. This unique feeding behavior typically occurs at twilight, though skimmers may also feed during the day.12