Calidris canutus
Order Charadriiformes
Family Scolopacidae
Subfamily Arenariinae
Adult in spring.— Upper parts gray, spotted with black and reddish-brown; rump and base of tail lighter; sides of head and under parts bay.
Adult in fall.— Upper parts bluish-gray; rump and base of tail white, barred with black; under parts bay, blotched with white.
Immature.— Upper parts as in fall adult; under parts white, without any bay; throat and breast streaked with dusky.
The Knot is a common migrant along the coast in May, and again in July, August, and September. It frequents mud-flats and sand-bars, but is also commonly found on the outer beaches. It is either stupid or else very unsuspicious, and allows a near approach. Old birds are easily recognized by their bay breasts; they may be readily distinguished from adult Dowitchers, which also have reddish-brown breasts, by the light color of their upper parts and by their much shorter bill. Young birds have light under parts, and must be recognized by the general light gray tone of the upper parts and the still whiter tail. Their note has been described as like the soft whit whit that one uses in whistling a dog back.
Hoffmann – A Guide to the Birds of New England and Eastern New York (1904)