Justification of Red List category
This species has a very small breeding range and population on two groups of islands in the South Atlantic Ocean, where it is susceptible to human impacts and stochastic events, which could drive the species to Critically Endangered or Extinct within a short period of time. Therefore, the species has been assessed as Vulnerable under criterion D2.
Luigi et al. (2008) have revised the previous population estimate of 15,000 individuals globally (Brooke 2004) to just 1,130 breeding pairs.
The species is presumed to be stable as there are no current major threats.
Pterodroma arminjoniana breeds on Trindade Islands off the coast of Espírito Santo, Brazil. It was considered abundant on Trindade in 1913 and 1986 (Murphy 1936, Filippini 1986). Surveys in the mid-1990s have indicated that the population on Trindade numbers 2,000-5,000 individuals (F. P. da Fonseca Neto in litt. 2000). The global population was estimated at 15,000 individuals (Brooke 2004), although recent estimates suggest the total may be as low as 1,130 breeding pairs (Luigi et al. 2008). Flocks have been noted flying around the Túnel, Pão de Açúcar, Farilhões and Crista de Galo peaks. Aerial courtship displays during daylight hours make the species very easily observeable, despite low abundance. From what was previously an unidentified Pterodroma species, the species was recently found to be breeding on Round Island, 22 km north of Mauritius, in the Indian Ocean (Brown et al. 2010). There have been confirmed sightings of several birds at sea in the central south Atlantic (490 nm northeast of Tristan da Cunha), off the Azores and a single sighting off Cape Verde Islands (Flood 2010). Geolocator trackings confirm they may regularly winter in the central North Atlantic (Ramos et al. in prep.). During breeding forage in a vast area around Trindade Island, from the Equator to 34°S, in deep waters. Apparently there is a staging area east of Trindade used by birds after breeding and before migration to North Atlantic Ocean (L. Bugoni and G.R. Leal unpubl. data).
It is present at Trindade Island year-round (all months) and breeds in two well-defined periods with some overlap and apparent fidelity of individuals at one period. Nests are located in crevices and other cliff-cavities in the highest parts of Trindade (Antas 1991) as well as down to sea level. The peak times for breeding activities (laying) are October and April (F. P. da Fonseca Neto in litt. 2000).
In the past, this species has been severely affected by invasive mammals. Feral cats decimated the seabird population and were subsequently eradicated in the 1990s (Alvez et al. 2011), they have since occasionally been seen on the island and, because of this, are thought of as relatively likely to return. Goats and pigs denuded the island’s vegetation, likely degrading Trinidade Petrel breeding habitat, but were eradicated in 2004 and 1965 respectively (Alves et al. 2011, Kruger et al. 2018). Mice are the only remaining invasive mammal on Trinidade Island and have been seen foraging eggs from seabird nests (Alves et al. 2011) as well as eating seeds thereby slowing the rate of vegetation regrowth, this is unlikely to have a significant effect on the Trinidade Petrel as it nests in relatively inaccessible areas with little vegetation.There is some potential for effects due to human development. The Brazilian navy expressed an interest in building a small airbase on the island, although this has not yet materialised, it would potentially cause habitat loss, degradation and the disturbance of birds. Experimental wind turbines have also been built, with plans to erect more in the future (Flood et al. 2015).
Conservation Actions Underway
Since 1967, Brazilian law has afforded protection to all seabirds by forbidding persecution, killing, colony disturbance and the use of bird by-products (Antas 1991). Goats and pigs denuded the island’s vegetation, likely degrading Trinidade Petrel breeding habitat, but were eradicated in 2004 and 1965 respectively (Alves et al. 2011, Kruger et al. 2018).
Conservation Actions Proposed
Designate the majority of Trindade as a federal reserve (Antas 1991) or national park (F. P. da Fonseca Neto in litt. 2000). Conduct an impact assessment before any construction on Trindade.
35-39 cm. Medium-sized, polychromatic petrel (dark, pale and intermediate plumages) with diagnostic white patch on underwing at the bases of primary feathers. Dark morph is wholly dark brown. Pale morph has very dark grey upperparts, white forehead-sides, and is white below with indistinct or well delimited grey breast-band. Black, deep and narrow bill, with strongly hooked nail, typical of the genus. Juvenile like adult. Similar spp. Dark morph is similar to Kermadec Petrel P. neglecta, but has pointed tail ,more white on underwing, but only separated from the Trindade petrel by absence of pale primary shafts in the upperwing and distinct call. Pale morph has less white on face and more on underwing than P. neglecta.
Text account compilers
Stuart, A., Symes, A., Temple, H., Anderson, O., Clay, R.P., Frere, E., Hermes, C., Fjagesund, T., Lascelles, B., Martin, R., Moreno, R.
da Fonseca Neto, F.P., Bugoni, L.
BirdLife International (2023) Species factsheet: Pterodroma arminjoniana. Downloaded from http://datazone.birdlife.org/species/factsheet/trindade-petrel-pterodroma-arminjoniana on 29/11/2023.
Recommended citation for factsheets for more than one species: BirdLife International (2023) IUCN Red List for birds. Downloaded from http://datazone.birdlife.org on 29/11/2023.