JUAN FERNANDEZ FIRECROWN Those who live by gardens can say that they know a
type of bird that hovers amongst the bees and butterflies: hummingbirds. These miniscule birds with needle-sharp beaks often have bright iridescent feathers and a heart rate of 1263 beats a minute, compared to the average human’s 70.1 During torpor, or the physical inactivity at night, the heart rate drops to 50 beats a minute in order to conserve energy. These small, seemingly restless birds have fascinated children as well as adults. However, of the 338 species, 34 are facing extinction.2 One such bird is the Juan Fernandez firecrown. The Juan Fernandez firecrown resides only on the island Robinson Crusoe, which is 667 kilometers off the coast of Chile and has an area of 47.94 square kilometers. Of this area, the Juan Fernandez firecrown’s habitat is limited to 11 square kilometers.3 Island Robinson Crusoe is part of the Juan Fernandez Islands, an island group unique for its rich biodiversity. However, this biodiversity can only be fully maintained if the Juan Fernandez firecrown continues to thrive.9 The island was first discovered in 1574, when a ship full of famished, disease-ridden British pirates wound up on its shore. The hotheaded Scottish navigator Alexander Selkirk demanded that his tyrannical captain Thomas Stradling leave him on the island, hoping that the rest of the crew would follow him and colonize. Unfortunately for Selkirk, the crew did not share his opinion. Selkirk was marooned on the island alone, but defied the odds when he survived and returned to England. Alexander Selkirk’s harrowing tale was the basis of author Daniel Defoe’s novel, Robinson Crusoe. Islands Robinson Crusoe and Alexander Selkirk are sister islands, both capable of supporting firecrown life. The Juan Fernandez firecrown, also known as the Sephanoides fernandensis, is about thirteen centimeters from head to tail tip. Males have a rusty orange-brown body with grey flight feathers and iridescent dark yellow crowns.3 Females, which are primarily green and white with iridescent blue crowns, have such a different appearance from males, that until the nineteenth century they were thought to be different species.5 These hummingbirds, once abundant centuries ago, are now critically endangered and face near-extinction. In 1969, there were only 459 birds on the island, a soberingly low amount.7 In 2008, there were 23 firecrown nesting pairs, 16 of which successfully raised young.6 Due to recent awareness and conservation efforts, the popula-
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tion has now risen to about 2500-3000 birds total, with around 17002000 at the age of maturity.3 This number, however, is decreasing at a rate of 1-9% every year.5 On Island Alexander Selkirk, the firecrown was last recorded in 1908 and is assumed to be extinct.3 These birds suffer mainly because of humanity’s lack of notice and care. Firecrowns are at risk due to the increase of invasive plants and the loss of their natural vegetation. While their natural vegetation includes Raphithamnus venustus flowers and Dendroseris litoralis flowers, the introduction of eucalyptus (Eucalyptus globulus) and garden flowers by humans throws the lives of the hummingbirds off-course. 75 percent of all native plants have disappeared due to burning, deforestation, and invasive species.3 Because invasive plants are being placed in Island Robinson Crusoe, the natural vegetation that the hummingbirds live off is vanishing. The ecological ruin is caused by the direct mass removal of vegetation and the introduction of herbivores such as rabbits and goats which cause environmental erosion.7 In fact, rabbits, which were introduced in 1935, are one of the main reasons for the lack of natural vegetation. They predate on native flora and desertify the soil, reducing the rich humus to dust.7 The number of rabbits is immense, with twenty rabbits a hectare, which is a thousand square meters.7 Carnivorous animals such as rats, cats, and coatis have been documented predating on the firecrowns and may play a cause in the decline of the species as well.3 Other birds on the island, such as the green-backed firecrown (S. Sephanoides) and the austral thrush (Turdus falcklandil) serve as a threat to the Juan Fernandez firecrowns. Thrushes predate firecrown nests, and green-backed firecrowns cause competition, but these serve as natural threats that would remain regardless of the introduction of invasive species through humans. When in torpor, these birds are very vulnerable because they are easy to approach and attack.3 However, the Juan Fernandez firecrown’s ability to defend itself may differ according to sex. The main competitor for resources is the green-backed firecrown. While the larger males are able to defend themselves, the smaller females suffer from interference. These two species prefer different nesting sites, but due to the lack of organic vegetation and nesting area, the green-backed firecrowns have relocated to the breeding areas used by the Juan Fernandez firecrown, thus causing significantly greater competition amongst the species.3 Due to recent notice, conservation actions have been set in place. The Juan Fernandez Islands were designated as a National Park in 1935 and an UNESCO Biosphere Reserve in 1977. Since 1997, several major campaigns have sought to restore the habitat. The Juan Fernandez Islands Conservancy, along with the American Bird Conservancy Conservation International, the Hummingbird Society, and the Royal Society for the Protection of Birds, are leading the attempt to save the firecrowns.