At the beggining of the game, you will pass by a bridge with a sunset on the back and a bubch of dead samurais, just pass it and continue on until you enter a cave and theres a big hole that you can jump to, dont jump yet, go back to that bridge, stand on the right side so you can see the sunset and make Samanosuke face the sunset and press and hold (O), and in about 20 to 30 seconds you should see the birds and the trophy.