Red-tailed Tropicbird Phaethon rubricauda


Justification of Red List category
This species has an extremely large range, and hence does not approach the thresholds for Vulnerable under the range size criterion (Extent of Occurrence <20,000 km2 combined with a declining or fluctuating range size, habitat extent/quality, or population size and a small number of locations or severe fragmentation). Despite the fact that the population trend appears to be decreasing, the decline is not believed to be sufficiently rapid to approach the thresholds for Vulnerable under the population trend criterion (>30% decline over ten years or three generations). The population size is very large, and hence does not approach the thresholds for Vulnerable under the population size criterion (<10,000 mature individuals with a continuing decline estimated to be >10% in ten years or three generations, or with a specified population structure). For these reasons the species is evaluated as Least Concern.

Population justification
The global population is estimated to number 70,000 mature individuals (Partners in Flight 2019).

Trend justification
The population is undergoing a small decline (Partners in Flight 2019).

Distribution and population

The Red-tailed Tropicbird breeds in tropical and subtropical areas of the Indian and Pacific ocean (Schreiber and Schreiber 2020). It typically breeds on islands, but can also be found on the south-west coast of Australia.


This species feeds mostly on fish, especially flying-fish, large quantities of squid and occasionally crustaceans. Prey is caught by plunge-diving, but flying-fish can be taken in flight. Breeding occurs seasonally in loose colonies on small, remote oceanic islands mostly on inaccessible cliffs. No regular migrations are known; adults can be found in the vicinity of colonies all year round (del Hoyo et al. 1992).


Rats have caused significant losses in Red-tailed Tropicbird colonies in the past and they remain vulnerable to further introductions throughout the range. It does, however, occur on many currently predator-free islands and has been shown to benefit from eradications that have been carried out to date (VanderWerf et al. 2014).


Text account compilers
Martin, R., Hermes, C.

Butchart, S., Calvert, R., Ekstrom, J., Fjagesund, T. & Stuart, A.

Recommended citation
BirdLife International (2023) Species factsheet: Phaethon rubricauda. Downloaded from on 29/09/2023. Recommended citation for factsheets for more than one species: BirdLife International (2023) IUCN Red List for birds. Downloaded from on 29/09/2023.