The Blue-and-black Tanager’s nest is cup-shaped and comprised of moss and densely interwoven rootlets that act as the outer shell of the nest. The exterior rootlets are lined with bamboo leaves (Chusquea), while the internal lining is made up of pale fibers and dark animal hair (Greeney et al. in press). Greeney at el. (in press) discovered two nests in Napo Province, northeastern Ecuador, that were similar in size, measuring 8 cm wide by 7 cm tall externally and 6 cm wide by 3 cm deep internally. The first nest, initially found on 10 June 2008, was 5 m above ground supported by multiple upright forks of a small Euphorbiceae. It contained two eggs that were pale blue in color with cinnamon speckles and blotches. The dimensions of the first egg was 20.2 by 14.1 mm weighing in at 2.1 g; the second egg measured 20.3 by 14.5 mm and weighed 2.2 g. The second nest (found 24 May 2009) was located at an elevation of 3350 m overhanging a small river at Termas Papallacta. It was 3.8 m high up in a 5 m tall tree and contained two eggs. Both eggs were similar in appearance to the eggs found at the other nest and measured 20.0 by 15.0 mm. In addition to these nests, two additional nests are also recorded in June in Colombia (Hilty and Brown 1986). Hilty and Brown (1986) also provide the following additional information regarding the timing of breeding of this species in Colombia: breeding condition birds recorded February to August, begging young recorded in January, fledglings recorded in May.