Thread: What kind of bird is this?

Have two of these nesting in a tree in our yard. Back and forth in a big hole. These birds are big, some kind of duck or goose. Nest is big in an old dead tree:





Haven't a clue what they are, thought I'd ask you fellas. Ann just took the pictures, so kinda dark. Cool as can be to me. They'd been busy, please let me know what they are - I need to know. Life in the country. Thanks.