Figure 1. This male, a second male and one or two females appeared on a reservoir in Res. Ecol. Mãe-da-Lua in the rainy season 2008, and stayed for a few weeks (or maybe longer, I did not follow up).
In appropriate light, the incredibly sky-blue bill of the male is very striking, even from a long distance. The male must hide well if he does not want to be noticed.

Figure 2. Female.