The Great Knot (Calidris tenurostris) is a medium-sized shorebird with a straight black bill and short olive legs. Great Knots are sometimes difficult to tell apart from the closely related Red Knot (C. canutus). A neat trick to help distinguish a Great Knot from a Red Knot is to imagine the beak turned around 180 degrees. If the length of the beak extends beyond the length of the head, it is a Great Knot. If it is shorter than or about the same length of the head, it is a Red Knot.