Even non-birders are familiar with Mallards. They are vocal, brightly colored (at least the males for much of the year) and can be quite tame in urban areas where they are often fed.
Males (called drakes) have brown chests, green heads, and yellow bills. When you hear the word Mallard, you probably picture a drake.
Females (called hens) are patterned with brown and black and have dirty-orange bills. Hens make the familiar loud “Quack Quack” calls.
Spend enough time looking through groups of Mallards and you're likely to come across an odd bird. The photo above shows a hybrid cross of an American Black Duck and a Mallard.
Now for a quick activity. Pick out the drake Mallards in the above photo. Now the hens. Now locate the hybrid duck. Are there any birds left? Who might they be?