Considering the energy-rich nature of nectar as a food source, it attracts a large range of visitors apart from the hummingbird, which has often coevolved with a plant to be the flower's most efficient pollinator. These other visitors, because they are not designed to access the well-hidden bounty of nectar, often damage the flowers (for example, piercing them at the base) and prevent further nectar production. "P. gigas", because of its high energy requirements, is known to alter its foraging behaviour as a direct response to nectar robbing from other birds and animals, and this reduces the viability of the hummingbird in an area with many nectar robbers, as well as indirectly affecting the plants by reducing pollination. If alien species are introduced that become nectar thieves, it is reasonable to predict that their activities will significantly impact the local ecosystem. This could prove to be a future risk for "P. gigas" populations because they sit close to the physical limit in their metabolic demands.