The first photo shows that steep forehead. The female is more difficult to identify. The best way I have found to positively identify a female Gad is when you see them in the proximity of male Gads. They look a lot like a small Mallard hen. The female is more brown overall, and the sides of the bill are yellow-orange.
Gads swim very high in the water and fly very swiftly.
Gads like freshwater lakes and quiet marshes. They are rarely seen on ocean estuaries. Gads are shy birds and are very adapt at blending into the local aquatic vegetaion. They are dabbling ducks, so they will be found in shallow water. There are two distinct populations of Gads.