Juvenile (top) and adult (bottom) Canada Goose. 19 Oct 2009. Concord, MA. Photos copyright David Sibley.
Differences apparent in these photos are:
- Juvenile overall has lower contrast markings, especially blurry and obscure pale edges on back feathers
- Juvenile has all feather tips narrow and rounded, vs adult feather tips broader and more square or flat-tipped. This creates a strongly barred pattern on the adult with pale lines straight across the back and well-marked pale and dark bars on the flanks.
- Juvenile has neck not quite as dark blackish as the adult, and the dark neck blends into the paler breast color; vs the adult has a truly black neck (in shadow in the lower photo here) with very distinct edge and no blending to pale breast (but in some dark western subspecies the black neck may blend into a dark brown breast even on adults)