Preheat a gas grill to high, or build a hot fire in a charcoal grill. Combine the peach jam and vinegar in a medium bowl and whisk to combine. Toss the quail knots with the olive oil and season with salt and pepper. Grill over high heat for about 3-4 minutes, then turn the quail knots. Remove the quail to the bowl with the jam and vinegar and toss to coat. Place the quail back on the grill and grill for about 30 seconds, then turn again. Serve immediately.
