This species seems to be of the duck, goose and swan family. I assume they are blue-winged teal based on the notable white stripe on the bird's head between it's head and beak. Upon research, I figured out that a notable difference can be examined between male and female Blue-winged teal, with these two fine fellas being male.
From a distance they seam to be the average size of a regular adult sized duck.
Not a great photo but this looks the closest to what I think it looked like. They were moving around a lot