In the air or at rest, black skimmers (Rynchops niger) are peculiar. No other bird has a lower mandible longer than the upper. As it skims the coastal waters for fish, the skimmer's distinctively long lower bill is clearly visible as it seizes small fish with a sudden snap, much to the delight of dusk or dawn boaters and beachcombers. At rest, the bird's bright red bill tipped in black, its short, red legs and long body distinguish it from its cousins, the more ordinary terns.

Flocking on beaches during the day as they wait to fish at dusk, skimmers line up facing the wind. Their slit eyes, which reduce the glare off sand and water, give them the appearance, at rest, of old men nodding off into naps. During colder months, they seek warm asphalt and crouch or lie on it to warm their bodies.

Dusk brings resting skimmers alive, especially in the dark of the new moon when fish cannot see them clearly. As one they rise, airborne in beautiful synchronized flocks, turning and fishing along the surface of the water in perfect coordination. Unlike other sea fishers, they prefer night fishing because the water is calmer and more fish are near the surface.

Flying close to the surface is efficient. Skimmers' very long wings take advantage of an aerodynamic phenomenon known as ground effect. The patterns of airflow around a wing are modified by the surface to reduce drag, and skimmers can tilt their heads down, bills open, and scoop up fish near the surface.

Like most other terns, they are ground nesters, making them vulnerable in populated areas. Florida wildlife officers often put up barriers to protect them from beachgoers during nesting season. Tread lightly.