Peel the pears and place in a saucepan with the other ingredients. Bring to the boil and simmer, uncovered until tender. Keep turning the pears so both sides imbibe the wine and flavourings. Cool in the liquid.
Wipe the grouse and season inside and out with salt and pepper. Smear them with butter, placing a knob inside each cavity. Place them, breast-side down in a buttered roasting pan