The American Crow is superficially similar to the Fish Crow, but is bigger (40–53 cm in length) and has a less silky smooth plumage by comparison.
Typically, Fish Crows have been restricted to the coastline from southern New England to Texas, but in the last few decades have been expanding their range, especially inland up large rivers.
The differences are often only really apparent between the two species when seen side by side or when heard calling.
Nonetheless, differences apart from size do exist.
Fish Crows tend to have smaller bills and slender feet.
However, bill size varies quite a bit in American Crows, with males having larger bills.
​A small billed female American Crow can have the same look in the face as a Fish Crow.
There may also be a small sharp hook at the end of the upper bill.
Fish Crows also appear as if they have shorter legs when walking.
The voice is the most outwardly differing characteristic for this species and other American Crow species.
The call of the Fish Crow has been described as a nasal "ark-ark-ark" or a begging "waw-waw" while the most common call of the American Crow is a distinct "caw caw".

Whitefield, New Hampshire, USA, 4 August 2017