Gray-cowled Wood-Rail is the most widespread species of Aramides, occurring from southwestern Costa Rica south to northern Argentina. This species primarily occupies swampy forest and forest edge, and the margins of forest streams, and also occurs in mangroves and the edges of marshes. Gray-cowled Wood-Rail usually remains under vegetative cover or in thickets, but sometimes ventures out in the open. The diet is mostly invertebrates, but presumably includes small vertebrates such as frogs, and perhaps also seeds, berries, and palm fruits. The nest is a platform of twigs and grasses, placed in a bush or tree, up to 3 m above the ground, and often above water. Gray-cowled Wood-Rail and Russet-naped Wood-Rail (Aramides albiventris) formerly were considered to be a single species, Gray-necked Wood-Rail. They differ in several ways, however, including in plumage (the rufous nape is reduced or absent on Gray-cowled Wood-Rail) and in vocalizations. The two species also replace each other very abruptly in Costa Rica, with Gray-cowled reaching its northern limit in southwestern Costa Rica, and Russet-Naped Wood-Rail from northeastern Costa Rica north to eastern Mexico.