The red-billed tropicbird is the largest of the three tropicbird species, a group of graceful seabirds best known for the two extremely elongated central tail feathers. Named for its crimson beak, which is stout and slightly downward-curving, the red-billed tropicbird has a mainly white body, and can be distinguished by its black wing tips and fine black barring on the upperparts. There is also a long black stripe through the eye. The male and female are similar in appearance, but the male may have longer tail streamers, while juveniles have a yellow beak, stronger barring on the back, eyestripes that meet on the back of the neck, and lack the long tail streamers. The short legs are set far back on the body, and the feet are webbed.