The air, especially at night, is full of souls — souls of the dead, souls of departed and powerful shamans, and what my teacher doña María Tuesta called almas olvidadas, forgotten souls, the wandering spirits of those who were neglected and abused while alive. The wandering and sorrowful soul of a dead person may appear as a being called a tunchi. An evil spirit of the dead, driven by malignancy rather than sorrow, is called a maligno or an alma mala, an evil soul.

The tunchi is a wandering bodiless spirit that cannot be seen, but can be recognized at night by its mournful whistle; as César Calvo says, few have seen it; many have heard it; everyone fears it. A tunchi is the departed soul of a deceased human being; children are taught that a whistle at night is a spirit of the dead. Tunchis may cause sickness, especially the sickness called mal aire, bad air; and the souls of the murdered dead seek revenge. But, although frightening to encounter, mostly tunchis are pathetic creatures, often birdlike, who can be kept away by tobacco smoke. But you must never mock a tunchi, for the infuriated soul will chase you, whistling, so that even the most courageous become panic-stricken, fleeing to madness or death. People in Iquitos may present themselves as skeptical, but, when pressed, everyone has a story about meeting a tunchi — or something that might have been a tunchi.

Sometimes tunchis are those who have suffered a particularly tragic death, especially by drowning; sometimes humanlike ghosts of the drowned can be seen in phantom canoes, moving upriver, back toward their former homes. You can hear them drifting alone in the jungle night, whistling like birds, like sorcerers. This is closely related to a widespread belief in almas que recogen sus pasos, souls retracing their steps — the shadowy souls of the still living visiting, shortly before their death, the places where they have lived. “I saw him walking on the street,” someone will report, “and he was in the hospital dying!”

These beings of the air are often associated with a disease of children called mal aire, bad air — the source of our word malaria. The belief in mal aire is widespread in South America; it occurs, doña María told me, when “something evil passes by” — almas malas, malignos, demonios, tunchis. The disease can be contagious. When adults, out at night, encounter one of these wandering souls, it can touch them as they pass by — a shock, a shiver, an apprehension — and then they can bring the sickness home to their children. When such invisible vaporous malignancies pass by a baby, the symptoms resemble those of susto — diarrhea, vomiting, unrest, fever — not an uncommon childhood syndrome, often diagnosed in North America as a result of the invisible vaporous malignancy called a virus.

There are different types of mal aire. Illness produced by the spirit of a dead person may be called mal aire de difunto. There can be mal aire del monte, evil air from the jungle, and mal aire del agua, evil air from the water. The cure for this sickness is a baño, bath, pungent with flowers and spices. The child should be bathed in this rapidly, doña María taught me, and the baby’s head, soles of the feet, and palms of the hands all sealed with crosses, made with agua de florida.

There is a striking relationship between these wandering souls and nocturnal jungle birds. Take, for example, the ayaymama, potoo (Nyctibius spp.). The name ayaymama reflects the belief that these birds are transformations of children abandoned in the jungle by their mother, and their disconsolate cry asks, Ay ay mama, why have you abandoned me? During the day, the birds perch motionlessly out in the open, on the ends of branches or broken-off stumps, virtually invisible in the jungle, with their mottled brown or gray coloration. At night they hunt flying insects in swooping flycatcher-like flights from their exposed perch.

At night, too, their eyes are highly reflective, and their brilliant eye shine can be seen even at great distances; their cry, heard especially on moonlit nights, is one of the most haunting sounds of the jungle — melancholy and lamenting, a series of loud wailing notes that gradually descend in pitch. The cry starts out loud enough to be startling if you are close; and, as you turn toward this mournful sound, there in the moonlit darkness you see the shining and apparently disembodied eyes.