The very limited information on the reproductive biology of Gray-and-gold Warbler is from Miller et al. (2007). who reported a nest with four eggs from Peru in early December, and a nest with two well feathered nestlings in Ecuador in late April. These dates are during the local wet season (typically December-May).
The nest is a domed cup, sited on the ground; one nest was on a steep slope, and the other on the side of a steep ravine. External nest dimensions are 12-13 cm wide and 9.5 cm tall (n = 1), with a side entrance that is 5-6 cm wide x 4 cm high (n = 2); the internal nest dimensions are 5 cm wide x 3.5 cm deep, with a total chamber height of 9.0 cm (n = 1). The dry weight of the nest is 10.70 g (n = 1), which is significantly less than the dry weight of nests of the sister species, Russet-crowned Warbler (Myiothlypis coronata); Russet-crowned Warbler occurs in higher elevations, with a cooler climate, and so may benefit from a heavier, more insulated nest (Miller et al. 2007). The dome and the body of the nest is composed primarily of dry grass and plant fibers, all loosely interwoven; the nest linings are composed primarily of dry grass.
The eggs are cream, marked with pinkish orange and reddish brown speckles, which are more concentrated at the larger end. Egg dimensions are 14.8-15.1 mm x 19.9-21.0 mm (n = 4).
The bird incubating in the nest with eggs performed a brief distraction display when flushed from the next. Both adults provisioned the young at the nest with two nestlings.