Which specific nesting behavior distinguishes the Wood Duck within the Family Anatidae?

They regularly nest in natural tree cavities.

Within the broad Family Anatidae, which encompasses most ducks, geese, and swans, the Wood Duck exhibits a highly specialized reproductive strategy that sets it apart from the majority of its relatives. While most waterfowl in this family typically choose to build their nests on the ground or in shallow depressions close to the water, *Aix sponsa* is noted as one of the few North American ducks that consistently seeks out and utilizes natural tree cavities for nesting. This obligate requirement links the species strongly to mature forested wetlands and bottomland streams where such nesting sites are available. This characteristic nesting habit is so critical that it directly informs modern conservation strategies, emphasizing the need to preserve standing, mature trees near water sources to ensure local population success.