The first case of overlapping broods for the Red-tailed Comet (Sappho sparganurus) is documented. While feeding 2 chicks from a first brood, a female simultaneously began to build a second nest and successfully raised 2 young in each. The length of overlap of the 2 nests was estimated at 17 d. This is the first record of partial nest overlap for a hummingbird species in a temperate area in the Southern Hemisphere. In addition, these observations extend the altitudinal limit of this species 260 m below the previously lower boundary, which was for the nonbreeding season. Received 23 August. Accepted 6 March 2017.