Larry B. Spear and David G. Ainley report that Markham's storm petrel has a more leisurely flight pattern than that of the black petrel, and state that Markham's storm petrel has a similar flight pattern to Leach's storm petrel. In 1980, Canadian author RGB Brown stated the birds tended to glide over two observations, with shallow and rapid wingbeats, though an observation by American ornithologist Rollo Beck described its wingbeats as slow, and slower than the wingbeats of Wilson's storm petrel Oceanites oceanicus and Elliot's storm petrel Oceanites gracilis. Unlike the black petrel, Markham's storm petrel typically flies greater than one meter over the ocean surface. Distribution and habitat Markham's storm petrel inhabits waters in the Pacific Ocean around Ecuador, Peru, and Chile, though sightings have occurred on the equator west of the Galápagos Islands, within the Panama Bight, and off of Baja California. Sightings off of Baja California might mistake Markham's storm petrel for the black storm petrel due to difficulties of distinguishability in the field. Spear and Ainley observed Markham's storm petrel from to , which expanded its westward range from a compilation of sightings recorded by ornithologist Richard S. Crossin in 1974. Its presence is highly unlikely in the Atlantic Ocean outside of freak vagrancies, and in 2007, Spear and Ainley classified the species as endemic to the Humboldt Current. Despite its range, Markham's storm petrel only nests in Peru and Chile. A survey conducted by Spear and Ainley from 18°N to 30°S, west to 115°, found greatest densities of the bird during austral autumn (the non-breeding season) offshore between Guayaquil and Lima. During spring, the breeding population splits into two around southern Peru and northern Chile, stretching out offshore. Nesting colonies were first reported in the late 1980s to early 1990s. In 1992, 1,144 nests, equal to a population of approximately 2,300 nesting pairs, were found inland on Paracas Peninsula in Peru. Two separate discoveries occurred in Chile in 2013: one of nesting sites south of the in Arica Province by a group of ornithologists and one of a recording of a bird singing by a biologist working for a consulting company. After further exploration in November 2013 based on the recording, in 2019, populations of 34,684 nests in Arica, 20,000 nests in Salar Grande, and 624 nests in Pampa de la Perdiz were found in the Atacama Desert of northern Chile. This translated to about