All of them involve new ducks from the DLC, all are passive and require no interaction. Two will happen fairly quickly on their own, one requires a little luck.


- yellow duck with green beak and eyes on the top row, immediately to the left of the one large duck. It's a sponge and will slowly grow bigger as it absorbs water. Once it hits a certain size, the achievement pops


- the only large duck in the DLC. Once collected, just wait until night and the lights will turn on by themselves.


- bottom row, second from the left. It has a little inflatable flamingo, that needs to be popped by one of the ducks with a pointy object (blowfish, knife, lance). Mine was popped by the pink duck with the party hat, 2nd from the right under "Events".


And credit to u/RoyalMaidsForLife on reddit for their efforts of finding the achievements