From Wikipedia: the Southern Lapwing (Vanellus chilensis) is a wader in the order Charadriiformes. It is a common and widespread resident throughout South America, except in densely forested regions (e.g. most of the Amazon), the higher parts of the Andes and the arid coast of a large part of western South America. This bird is particularly common in the basin of the Rio de la Plata. Tero, Teru, Tero-teru are the common names given by the guaraní people and they are onomatopoeias of the sound they make.