Ducks have graced waterways for centuries, and many species of ducks have easily found cavities in nearby trees to use as a nesting site. In areas where trees are scarce, some ducks take readily to manmade housing. Placing a duck house near the water helps attract them to the home, and to protect nestlings on their trek to the pond or lake. Each nest box should include a rough interior, so the ducks can easily exit it when ready. Duck houses are most successful with an oval shaped entrance hole. Wood ducks prefer holes 4" by 3", while buffleheads, goldeneyes, and mergansers prefer slightly larger entrances, such as 3.25" x 4.125". Mount the house 5' to 15' high, and as close to the water as possible. Help bolster specific duck populations using a duck house near your pond or lake.