On Hunting (5.18-5.19)

When being pursued they are most conspicuous across ground that has been broken up, if they have some red in their coats, or across stubble, owing to the shadow they cast. They are also conspicuous in game paths and on roads if these are level, since the bright colour of their coats shows up in the light. But when their line of retreat is amongst stones, in the mountains, over rocky or thickly wooded ground they cannot be seen owing to the similarity of colouring.

When they are well ahead of the hounds, they will stop, and sitting up will raise themselves and listen for the baying or the footfall of the hounds anywhere near; and should they hear the sound of them from any quarter, they make off.