How to Identify a Wood Duck (Aix sponsa)

• Head pattern: Male: iridescent green, blue, and purple head with white lines from the base of the bill and from behind the eye out onto a distinctive crest
• Head pattern: Female: gray head with a hint of a crest, dark back, and a white eye-patch (teardrop) around the eye
• Wing patch (speculum): Male and Female: dark wings with glossy green and blue iridescence and an iridescent blue speculum with a trailing white edge
• Body pattern: Male: chestnut breast with rows of white spots, goldish flanks with fine dark vermiculation, white belly
• Flight silhouette: Heavier-bodied with broad wings and tail, lacking the choppy, fast wingbeats of Hooded Merganser

Wood Duck is heavier-bodied with broader wings and tail and lacks the Hooded Merganser's choppy, fast wingbeat in flight The Hooded Merganser page lists its own marks.

Wooded swamps, rivers, ponds; favors shallow inland lakes, ponds, and slow-moving rivers surrounded by deciduous or mixed woodland Breeds across the eastern and Pacific Northwest US and southern Canada; northern birds migratory, southern females may be permanent residents

Shoot from water level if you can, with the sun behind you, so head pattern and the wing patch show their true colors. Get one frame with the bird side-on and one as it stretches or flaps, which exposes the speculum and belly. Note who it is swimming with; ducks flock by species. The app names the likely species; confirm with the marks above, and check the female separately, since females of many ducks look alike.