It breeds in the humid highlands at 300-900 m, in burrows or natural cavities, on slopes, in craters, sinkholes, lava tunnels and gullies usually in close proximity to Miconia plants (Baker 1980, Cruz and Cruz 1987, 1996). It feeds mostly on squid, fish and crustaceans (Castro and Phillips 1996). On San Cristóbal, nests were primarily located along ravines in areas of dense Miconia robinsoniana and native fern cover, with the majority of egg-laying taking place between May and October, peaking in August (Cruz-Delgado et al. 2010a).

Pterodroma phaeopygia is endemic to the Galápagos Islands, Ecuador, breeding on Santa Cruz, Floreana, Santiago, San Cristóbal, Isabela and possibly other islands in the archipelago (Cruz and Cruz 1987, H. Vargas and F. Cruz in litt. 2000). Between 1978 and 1980, populations on the islands were estimated at 9,000 pairs on Santa Cruz (Baker 1980), c.11,250 on Santiago, and c.6,750 on Floreana and San Cristóbal (Tomkins 1985). By 1985, the Santa Cruz population had plummeted to 1,000 pairs, that on Santiago to less than 500 pairs (Cruz and Cruz 1987), and numbers on Floreana and presumably San Cristóbal were estimated to have declined to c.2,000 pairs (Coulter et al. 1981). An extensive survey of Santa Cruz in 2005 located c.300 previously unknown nests, but the island population totalled just 700 pairs (Valarezo 2006); a further survey in 2010 calculated 1,135 pairs (Valarezo and Heitmann 2011). Estimates in 2008 suggested a total of 4,500-5,000 active nests on all five islands (I. Guzmán in litt. 2008). Birds forage around the islands, but also disperse east and north towards South America and up to 2,000 km south (Spear et al. 1995). The species has recently been recorded off the coast of Peru, and records in Baja California could be this species or Pterodroma sandwichensis (Carboneras et al. 2015).

Conservation Actions Underway
CMS Appendix I. In 1982, predator control commenced in the Cerro Pajas colony (c.2,000 pairs) on Floreana (Cruz and Cruz 1996). Predator control involving intensive rat baiting around known colonies and petrel monitoring currently continues on Floreana, Santa Cruz, San Cristóbal and Santiago (H. Vargas and F. Cruz in litt. 2000, D. Wiedenfeld in litt. 2012). In early 2009, it was confirmed that goats have been successfully eradicated from Santiago (American Bird Conservancy 2009). A small number of burrows have recently been discovered on Alcedo, Isabela (Cruz-Delgado 2005). The islands are a national park and were declared a World Heritage Site in 1979. World Heritage Site designation encourages Ecuador to work carefully to enact suitable conservation laws and implement existing laws to protect the unique fauna and flora of the Galápagos Islands. There are proposals to protect more marine key biodiversity areas within the Galápagos Marine Reserve by amending the existing marine zoning scheme to reduce the impact from fishing (Edgar et al. 2008). The wind turbine development includes a series of mitigation and enhancement measures that will be instituted during implementation, many focusing on the Galapagos Petrel, and it is intended that these measures will not only act to minimise impacts but may actually help increase the population. A long-term monitoring programme is included as part of the project activity and ongoing operations (Anon. 2008). Exotic vegetation is being controlled with the help of local landowners on Santa Cruz (Valarezo and Heitmann 2011).

Conservation Actions Proposed
Monitor breeding success under various predator control regimes to determine most appropriate management (M. de L. Brooke in litt. 1999). Continue rat control programs on San Cristóbal, Santa Cruz, Floreana, and Santiago islands (D. Wiedenfeld in litt. 2012). On San Cristóbal, remove invasive plants such as blackberry and guava and reforest with native plants, particularly Miconia robinsoniana (Cruz-Delgado et al. 2010a, D. Wiedenfeld in litt. 2012); on Floreana, continue to control Lantana; and on Santa Cruz, control Cinchona pubescens and blackberries (D. Wiedenfeld in litt. 2012). Continue searching for nesting grounds in agricultural areas which are not protected through the park system on Santa Cruz and Isabela (B. Hennessey in litt. 2008). Conduct a full census for the species as the last comprehensive surveys were in the 1980s and late 1990s (not complete). Ensure wind-power plants are situated so that they do not affect nesting areas or sites with Miconia, and that power lines are buried to prevent aerial collisions as the birds return to their colonies at night. Implement a post-construction monitoring programme on San Cristóbal to assess long-term effects of the turbines (Cruz-Delgado et al. 2010b). Determine potential effects of long-line fishing in the Galápagos Marine Reserve and elsewhere in the eastern Pacific and assess how to avoid them. Working with landowners in areas outside the park, create conservation easements to protect petrel nesting habitat. Create an education programme in the agricultural areas to motivate and educate landowners in habitat conservation (Valarezo 2012, B. Hennessey in litt. 2008). Create a species action plan involving local stakeholders (B. Hennessey in litt. 2008). Conduct rodent control campaigns around colonies on San Cristóbal. Conduct a Galapagos Petrel pride campaign with the Galápagos National Park (B. Hennessey in litt. 2008).