ninety-five percent of the known breeding population at the time. Behavior and ecology Markham's storm petrel nests in burrows, natural cavities, and holes in saltpeter crusts. Nests in saltpeter cavities have been reported in Pampa de Camarones in northern Chile, and inland on Paracas Peninsula. In Peru, egg laying occurs from late June to August; in Chile, an analysis of three colonies in the Atacama Desert found a five-month reproductive cycle, from arrival at colonies to departure of fledglings, across all three colonies, though pairs could reproduce asynchronously. This could lead to an overall ten-month reproductive season. Pairs produce one egg per season, and adults in nests were found to vocalize when a conspecific recording of vocalizations was played at the entrance to the nest. The average incubation period in Paracas is 47 days (n = 28). Both the female and male engage in duties related to incubation. The shifts in incubation lasted three days or less in Paracas. According to Birds of the World, there are "[n]o details on the breeding colonies in Chile". Mean width of the widest part of openings to nest burrows in Chile was measured at with a standard deviation of ± , with the narrowest part measured at with a deviation of ± . The average depth of the burrows was greater than . After hatching, in Chile, the fledglings move towards the sea after a chick phase. Fledglings are either attracted to or disoriented by artificial lights, an occurrence common to burrow-nesting petrels. In a study by Spear, Ainley and William A. Walker of the National Marine Mammal Laboratory, a sample of fifteen Markham's storm petrel had consumed namely the fish Diogenichthys laternatus and Vinciguerria lucetia, among other foods. Markham's storm petrel was found to have a lower dietary diversity than other small petrels, though dietary diversity was high generally among small petrels compared to other birds analyzed. A 2002 study in Marine Ornithology found its main diet by mass consisted of fish (namely the Peruvian anchovy Engraulis ringens), cephalopods (namely the octopus Japetella sp.), and crustaceans (namely the pelagic squat lobster Pleuroncodes monodon), with about ten percent of analyzed stomach contents suggestive of scavenging. Based on large variations in the types of food it consumes, and its tendency to scavenge, biologist Ignacio García-Godos concluded Markham's storm petrel was a forager which opportunistically found food near the surface of the ocean. The proportion