Most current drones are designed with a static morphology aimed at exploiting a single locomotion mode. This results in limited versatility and adaptability to multi-domain environments, such as those encountered in rescue missions, agriculture and inspection, where multiple locomotion capabilities could be more effective. For example, hovering and terrestrial locomotion are complementary and can increase versatility by allowing the robot achieve speed and ease of obstacle negotiation during flight, or low power consumption and reduced noise signature while moving on the ground. With this aim, the paper presents the design and characterization of a multi-modal quadcopter with adaptive morphology by means of foldable arms. After landing, the quadcopter folds the frontal arms and uses whegs and tracks to move on the ground. The foldable arms allow to decrease the size of the robot in order to achieve more mobility in confined ground environments; to perform a self-righting maneuver if the drone falls upside down; and to negotiate large gaps by strategically unfolding them during terrestrial locomotion.