Willets are large, long-legged shorebirds with a grey or brown overall plumage. They are characterized by a distinctive white rump and broad white wing stripe that is visible in flight. Measuring 33 to 41 cm in length and weighing between 200 and 330 grams, they have a similar plumage pattern across sexes, though females are slightly larger. Their basic plumage is a plain gray, while their alternate plumage is darker, with a brownish appearance and barred or streaked patterns. In flight, the broad white wing stripe contrasts with the dark primary wing coverts, and they are known for their vocalizations. There are two main populations: eastern willets (Catoptrophorus semipalmatus semipalmatus), which are slightly smaller and darker, and western willets (C. s. inornatus), which are larger and paler. Their vocalizations, habitats, and physical characteristics vary between these two populations. Willets have greyish legs and a slightly webbed bill and toes.