portugal: One way to show the Eagle: arrows up-left, up-right, down. short lines up, right, left. longer lines down-left and down-right.

This is closest to how the current Shogi/MiniShogi pieces are: straight arrows for slides, curved arrows for jumps, lines for steps. (Mini)Shogi doesn't have pieces that can step two places though, hence the short/long lines.

Alternatively, I'd settle for images of falcons, geese, quails, eagles, cranes, swallows and phoenixes.