Markham's storm petrel (Hydrobates markhami) is a species of storm petrel in the family Hydrobatidae. An all-black to sooty brown seabird, Markham's storm petrel is difficult to differentiate from the black petrel Procellaria parkinsoni in life, and was once described as conspecific with, or biologically identical to, Tristram's storm petrel Hydrobates tristrami. Markham's storm petrel inhabits open seas in the Pacific Ocean around Peru, Chile, and Ecuador, but only nests in northern Chile and Peru, with ninety-five percent of all known breeding populations in 2019 found in the Atacama Desert. First described by British ornithologist Osbert Salvin in 1883, the bird was named in honor of Albert Hastings Markham, a naval officer who collected a specimen off Peru. Markham's storm petrel nests in natural cavities in saltpeter, and pairs produce one egg per season. After hatching, fledglings make their way to sea, and can be either attracted to or disoriented by artificial lights. The diet of Markham's storm petrel consists of fish, cephalopods, and crustaceans, with about ten percent of stomach contents traceable to scavenging according to a 2002 study. Since at least 2012, Markham's storm petrel has been listed as an endangered species in Chile, and, in 2019, the International Union for Conservation of Nature (IUCN) classified the conservation status of Markham's storm petrel as Near Threatened due to habitat loss on its nesting grounds. The (SAG), a department of the Ministry of Agriculture of Chile, has undertaken conservation efforts in the country. Taxonomy The northern storm petrel family, Hydrobatidae, is a group of seabirds characterized by long legs and a high adaption to marine environments, with its eighteen species predominately endemic to the northern hemisphere. In Hydrobatidae, Markham's storm petrel is a member of the genus Hydrobates, the only genus in the family, and is large compared to other members in the genus. Hydrobatidae probably diverged from other petrels at an early stage; according to John Warham, the petrel group had "substantial radiation" by the Miocene. Storm petrel fossils are rare; those which are found date from the Upper Miocene in California. British ornithologist Osbert Salvin first described Markham's storm petrel as Cymochorea markhami in 1883. Markham's storm petrel is named after Sir Albert Hastings Markham, a British explorer and naval officer who picked up the type specimen off Peru. The bird was thought by ornithologist James L. Peters in 1931 as conspecific, or biologically identical, with Tristram's