Red-tailed Tropicbird

The red-billed tropicbird, Phaethon aethereus, is a seabird of tropical oceans, bearing a superficial resemblance to terns. It boasts a predominantly white plumage with black markings on the wings and back, a distinctive black mask, and a striking red bill. Adult birds are noted for their elongated tail streamers, which can be twice their body length, with males typically sporting longer streamers than females. Three subspecies are recognized, each with subtle variations in size, plumage, and bill coloration.

Identification Tips

Adult red-billed tropicbirds are characterized by their white plumage, accented with black wingtips and finely barred backs. Their black masks extend from above the lores to the sides of the nape, often with gray mottling near the nape and hindneck. The underparts are pure white, with occasional black markings on the flanks. The bill is a vibrant red, while the legs and feet exhibit a mix of orange-yellow and black. Males are generally larger than females, with notably longer tail streamers.

Habitat

These tropicbirds favor nesting on isolated cliff faces, often forming loose colonies. They require clear takeoff paths for flight due to their limited walking ability.

Distribution

The red-billed tropicbird is found across the tropical Atlantic, eastern Pacific, and Indian Oceans. The nominate subspecies inhabits the southern Atlantic, while subspecies indicus is found in the Middle East and Indian Ocean waters, and mesonauta resides in the eastern Atlantic, Pacific, and Caribbean regions.

Behaviour

Capable of reaching speeds of 44 kilometers per hour, the red-billed tropicbird is an adept flyer, often seen cruising at least 30 meters above the sea. It is less proficient on land, requiring an unobstructed runway for takeoff.

Song & Calls

Near breeding colonies, the red-billed tropicbird is vocal, engaging in loud, harsh kreeeee-kreeeee-kri-kri-kri-kr screams with other adults. Disturbed chicks emit a piercing shriek, either rasping or reeling in nature.

Breeding

Breeding takes place in simple scrape nests on cliff faces, with both sexes sharing incubation duties for about six weeks. A single egg is laid, and chick fledging occurs after approximately 10 to 15 weeks. Breeding success is influenced by food availability and environmental conditions.

Similar Species

The red-billed tropicbird can be distinguished from the red-tailed and white-tailed tropicbirds by its red bill and white tail streamers. Juvenile red-billed tropicbirds have more heavily barred upper parts than their counterparts.

Diet and Feeding

These birds feed on fish and squid, captured by diving from the air into the water. They sometimes take advantage of surface-feeding predators, seizing prey driven to the surface.

Conservation status

The red-billed tropicbird is classified as Least Concern by the IUCN, though populations are believed to be declining. Threats include habitat exploitation and predation by invasive species such as rats and cats. In some regions, such as Brazil and Mexico, the species is considered threatened.