Adult crows are about 17 to 21 inches in length, while juvenile crows are about 10 inches in length, or about the length of a person's forearm. Juvenile crows have brownish-black feathers. Crows are all black including feathers, beak, legs and feet. The crow's nostrils are covered with bristles.
American Crow
Blue jays are 10 inches long, and have a black sturdy bill, and blue crest. They have a black eyeline and breastband and a greyish-white throat and underparts. The wings are bright blue with black bars and white patches. Blue jays have a long blue tail with black bars and white corners and dark legs.  
Blue jay