Markham's storm petrel (Hydrobates markhami) is a seabird native to the Pacific Ocean around Peru, Chile, and Ecuador.

The species is named after British explorer Albert Hastings Markham, who collected the specimen on which the scientific description was based.

The diet of Markham's storm petrel consists of fish, cephalopods such as octopuses, and crustaceans; about ten percent of stomach contents is traceable to scavenging.

[2][3] The species is named after Albert Hastings Markham, a British explorer and naval officer who collected the type specimen off the coast of Peru.

Therefore, all the species in Oceanodroma were transferred to Hydrobates, including Markham's storm petrel, which was accepted by the International Ornithologists' Union.

They differ from their southern counterparts, the Austral storm petrels (Oceanitidae), in having proportionally longer wings and shorter heads and legs.

Fossils of storm petrels are rare, but have been found in Upper Miocene deposits in California;[11] by this time, the Hydrobatidae had probably extensively radiated.

[15][4] A 2023 study found that there were three well-supported genetic clades of Markham's storm petrel, reflecting the Paracas, Arica, and Salar Grande colonies.

The fresh plumage is black to sooty brown with a dull lead-gray gloss on its head, neck, and mantle.

The covert feathers above this bar are often brownish, while the primaries below it are often blackish, resulting in a characteristic three-colored wing pattern.

Markham's storm petrel also differs in its shorter neck and more angular head, and in the more pronounced forking of the tail.

From Leach's storm petrel, it differs in its more pronounced tail forking, its longer wings, and larger size.

[15] Markham's storm petrel inhabits waters of the Humboldt Current in the Pacific Ocean off Ecuador, Peru, and northern Chile.

[23][19] A survey published in 2007 found that during austral autumn, the non-breeding season, the largest concentration of birds is just off the cost of Peru between Guayaquil and Lima.

[18][17] Despite its range, Markham's storm petrel only nests in Peru and Chile in the Atacama desert, in natural cavities in saltpeter (salt crusts rich in nitrates).

[24] Because the birds only return to their nests after nightfall and fly off again to sea before dawn, the detection of the breeding colonies is difficult, and their location had long been unknown.

[4][24] Two separate discoveries occurred in Chile in 2013: one of nesting sites south of the Acha valley in Arica Province and one of a recording of a bird singing.

[17] A 2007 study found that a sample of fifteen Markham's storm petrels had consumed the fish Diogenichthys laternatus and Vinciguerria lucetia, among other foods.

), and crustaceans (namely the pelagic squat lobster, Pleuroncodes monodon); about ten percent of analyzed stomach contents suggest scavenging.

Based on large variations in the types of food it consumes, and its tendency to scavenge, Markham's storm petrel appears to opportunistically forage near the surface of the ocean.

[32] The proportion of birds that feed or rest, compared to flying in transit, was significantly higher in austral autumn than spring according to the 2007 study.

[4] A 2018 study found the ectoparasitical stick-tight flea (Hectopsylla psittaci) on two birds out of ten captured in Pampa de Chaca within the Arica y Parinacota Region.

The turkey vulture (Cathartes aura) served as a possible source for the transition between hosts, as the two were observed nesting in the same colony.

[33] The International Union for Conservation of Nature (IUCN) estimated the population of Markham's storm petrel in 2019 as between 150,000 and 180,000 individuals, between 100,000 and 120,000 of them being mature.

[22][1] Reported threats include new construction and development especially of power lines, solar energy parks, wind farms, and roads, which may destroy breeding habitat; garbage from roads and landfills near the colonies, which can attract predators or be blown by wind to get stuck in and possibly block the entrances to nest holes; and military activities within the colonies.

[15][1] Bulldozer trails, dogs, and an encampment of road construction workers have been observed near nesting areas close to Arica.

For Chile, a 2021 study criticized that the existing environmental legislation is "weak, favours industrial productivity and is insufficient to preserve the storm-petrels of the Atacama Desert".

[29] The 2021 study suggested six management priorities to protect the storm petrels of the Atacama desert, including formal protection of colonies; regulation of infrastructure projects and other human activities to prevent impact on colonies; stricter environmental assessments for planned development projects that might affect breeding areas; the reduction of light pollution and the mitigation of its impacts; international cooperation; and further research.