Why are longer wings better?

Could you elaborate on why longer wings are considered advantageous? Is it due to their ability to generate more lift, enabling birds to soar higher and further? Or does it relate to improved stability and maneuverability during flight? Additionally, could the increased wingspan contribute to greater energy efficiency, allowing birds to expend less energy during long migrations? Understanding the benefits of longer wings in the context of biology and physics would be insightful. Could you provide some clarification on these points?