RED-BILLED TROPICBIRD Phaethon aethereus

YELLOW-BILLED TROPICBIRD Phaethon lepturus

The three species of tropicbird all have tropical distributions. Two species are found in the tropical Atlantic and both breed on Ascension Island, with the majority of both species breeding on Boatswainbird Island. The most numerous is the Yellow-billed Tropicbird, or Boatswainbird (so called because its call is likened to that of a Bosun's whistle) after which the island was named. About 1,000 pairs of Yellow-billed tropicbirds and 500 pairs of Red-billed Tropicbirds breed on Ascension. The Yellow-billed Tropicbird can be separated from the Red-billed Tropicbird by several characteristics: - the bill colour, if it can be seen, is a giveaway - the Yellow-billed Tropicbird has two thick, black, bars on each wing, while the inner wing of the Red-billed Tropicbird is finely barred black. - the Yellow-billed Tropicbird is a smaller bird than the Red-billed Tropicbird.