Tropical Shearwater Puffinus bailloni


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). The population appears to be stable and therefore does not 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 total population has not been quantified. Subspecies P. b. dichrous is estimated to number 1,000-10,000 pairs on the Line Islands and 10,000-100,000 pairs on the Phoenix Islands, with the nominate subspecies thought to number 3,000-5,000 pairs on Reunion and fewer than 100 individuals on Europa (reviewed by Brooke 2004). Nevertheless, there are thought to be many more breeding colonies on other islands in the Pacific.


On the Seychelles, where more than a third of the population resides, substantial numbers of birds become entangled in seeds of the native tree Pisonia grandis. In severe cases, birds are prevented from flying and subsequently starve to death or become easy prey. The overall effect on the population and its breeding success is unknown (Safford and Hawkins 2013). The population on Reunion Island (c. 5% of the global population), suffers from light pollution, resulting in c.300 chicks being grounded each year. This might be limiting recruitment in the local population (Le Corre et al. 2002).


Text account compilers
Martin, R., Fjagesund, T., Stuart, A., Hermes, C., Symes, A., Taylor, J.

Recommended citation
BirdLife International (2020) Species factsheet: Puffinus bailloni. Downloaded from on 26/09/2020. Recommended citation for factsheets for more than one species: BirdLife International (2020) IUCN Red List for birds. Downloaded from on 26/09/2020.