hummingbird to use its feet to groom, even though this takes longer than traditional beak methods. Preening is important to remove ectoparasites and spread oil across the feathers. Reproduction Breeding occurs from February to March. Nests are cup-shaped and made of moss, and are usually hung among root fibers high above the ground. Co-evolution with Passiflora mixta The sword-billed hummingbird displays extreme coevolution with the passionflower Passiflora mixta. The two species evolved together during the early radiation of the subgenus Tacsonia, because the species exclusively pollinated P. mixta. The position of the flower's anthers and stigmas, along with the length of the corolla tube, make it an inaccessible food source to nearly every species except the sword-billed hummingbird. This mutualistic relationship lets P. mixta depend on the bird for pollination, while the bird obtains a high-quality food source. To obtain nectar, the hummingbird will stick its long bill down the tube of the corolla (both of which are almost exactly the same length), drink, and then retreat and hover for a few seconds before repeating the process. Other species, such as insects, may be able to access the flower's nectar but do so by puncturing the base and feeding through a hole instead of the corolla tube. Additional evidence of coevolution is that both species also inhabit the same territory range along the Andean mountains. If sword-billed hummingbird populations were to decline, there would most likely be a negative impact on the abundance of P. mixta flowers due to their extreme coevolution. Status and conservation The sword-billed hummingbird is listed as being of least concern by the International Union for Conservation of Nature (IUCN) on the IUCN Red List due to its large range, lack of significant population decline, and lack of major threats. There is also no census on global number of individuals, because of the large range of occurrence and uncommon sightings. It has adapted to man-made habitats in some areas and is also known to occur in several protected areas. Climate change and deforestation are the two most probable threats to the sword-billed hummingbird as they may lead to habitat loss and a decrease in food sources, especially of Passiflora mixta. In art and media The BBC's documentary series Planet Earth II depicted the sword-billed hummingbird flying through the forest in the episode Jungles. References External links Video of female using feet for grooming, Internet Bird Collection