In the first image there are two female ducks and a male Cinnamon Teal, Anas cyanoptera. One or both of the females may be Cinnamon Teal but they also maybe Blue-winged Teal. If their heads weren’t beneath the water or turned so you can’t see their profile, you could look for the white patch of feathers found just behind the beak in Blue-winged Teal females. In Cinnamon Teal females, this patch is tinged with yellow if it is present and can be much smaller than with Blue-winged Teal, or completely absent. So, I refrained from calling them by either name. This points out how closely related these ducks are. They are in the family Anatidae and in the same subfamily Anatinae. They are found together throughout their range because of habitat and food preferences.
The second photo shows a male Cinnamon Teal who has mud halfway up his beak because he has been foraging there for food.
This image shows another male Cinnamon Teal with mud on his beak and forehead swallowing something tasty from deep in the mud. These creatures will eat water plants and seeds as well as tiny planktonic creatures they filter with their beaks.