About Agelasticus cyanopus (Vieillot, 1819)
The unicolored blackbird, Agelasticus cyanopus, shows clear sexual dimorphism. As its name suggests, the male has entirely glossy black plumage and dark eyes. The female has streaked brown and black plumage, with a yellow belly streaked with brown. She has a dark dark mask on her face, and reddish-brown wings edged with black. Female individuals from the lower Amazon region and southeastern Brazil have duller overall colouration, with less rufous wing colour and less yellow on the underparts. For this species, the legs and iris are black, and the bill is long and sharply pointed. Males can be confused with the velvet-fronted grackle or the chopi blackbird. This bird's call is a loud "tchew-tchew-tchew" that is sung from an elevated position. It also produces a variety of trills and rattling sounds that vary in tone and pitch. The unicolored blackbird is native to South America. Its range extends from northern Bolivia and southern Brazil to northern Argentina, and covers much of the lower Amazon region. It inhabits marshes, areas near the edges of ponds and lakes, and adjacent grassland. Its altitudinal range reaches up to approximately 600 metres (2,000 ft), and it is especially common in the Brazilian Pantanal.
