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Juan Fernandez Firecrown Sephanoides fernandensis



Justification

Justification of Red List category
This species has an extremely small range, restricted to a single island, where habitat loss, habitat degradation through invasive plants, predation by introduced mammals and possibly competition are causing continuing declines. It consequently qualifies as Critically Endangered.

Population justification
This species has a small population. Historical records indicate that densities on Robinson Crusoe were formerly much greater than the 684 individuals (varying between 804 birds in the austral summer and 445 in autumn) estimated in 1988-1989. Direct count surveys in 1995-1997 indicated that the population was in the low hundreds (Roy et al. 1999), and transect counts were used in 2001-2002 to estimate a total population of 1,258 individuals (Hahn et al. 2006). However, more thorough surveys conducted in 2005 and repeated in 2006, coupled with quantitative modelling, estimated population densities in different habitats and concluded that the global population is considerably larger: c.2,500-3,000 individuals (P. Hodum in litt. 2007, 2008). A survey in 2011 using line transect and banding counts estimated the population at 740 individuals, equating to 490 mature individuals; this figure is considerably lower than previous estimates potentially as a result of the tsunami in 2010 (Hahn et al. 2015); however, the population is thought to have recovered since (I. Hahn in litt. 2015). The fixed radius point count methods utilized in 2005 and 2006 were repeated in 2011, 2012 and 2014 and analyzed with a Bayseian state-space model elaboration on the original model yielding similar estimates ranging from 2,298 individuals in 2011 to 5,263 individuals in 2012 (E. Hagen in litt. 2020). This roughly equates to 1,500-3,500 mature individuals.

Trend justification
High-quality habitat is being lost and degraded, which may be causing slow population declines.

Distribution and population

Sephanoides fernandensis is endemic to the Juan Fernández Islands, Chile, where the nominate race is confined to c. 11 km2 on Isla Robinson Crusoe (Hahn et al. 2005). The race leyboldi is extinct on Isla Alejandro Selkirk, where it was last recorded in 1908.

Ecology

The species inhabits remnant native forests, on which it appears to be completely dependent for breeding (there is a strong negative correlation between the presence of non-native vegetation and the location of nests [P. Hodum in litt. 2007, 2008]). However, throughout the year it also utilises non-native plant communities, feeding on introduced plants, such as Eucalyptus globulus and garden flowers. This usage of non-native plants is especially common in the austral autumn and winter when only one native species (Raphithamnus venustus) flowers (Roy et al. 1999). It feeds on the endemic Cabbage Tree (Dendroseris litoralis) in late summer (Hahn et al. 2015). It is mostly nectarivorous, but small insects are taken from leaves or in flight. The proportion of insects in the diet increases during the chick-rearing period. The sex ratio is heavily skewed, with three males to every female (Roy et al. 1999). It may experience competition with S. sephaniodes, especially over access to Dendroseris litoralis flowers post-breeding, which may lead to spatial segregation during the post-breeding season (López-Calleja et al. 2006, Vizentin-Bugoni et al. 2017).

Threats

The clearance and degradation of vegetation by humans since the late 16th century and the impacts of herbivorous mammals (especially rabbits introduced in the 1930s) has limited the availability, quantity and quality of food resources. Wood harvesting at lower altitudes has contributed to the loss of native habitat (Roy et al. 2013). Habitat quality is also being degraded by the spread and dominance of invasive plants, most prominently by Elm-leaf Blackberry Rubus ulmifolius, Maqui Aristotelia chilensis and Murtilla Ugni molinae (Anon. 2005); this is feared to decrease the abundance and density of insects important for the species's diet (Hagen et al. 2010). In 2015, Eucalyptus snout beetles Gonipterus sp. were introduced; by 2019 they had infected a majority of trees and suppressed vigor and flowering, which has apparently affected the species's foraging behaviour (E. Hagen in litt. 2020). Introduced predators, such as rats, cats and coatis, have been implicated in the mortality of some birds, and may be responsible in part for its decline (Roy et al. 1999, Hahn and Römer 2002), although long-term monitoring during the breeding season has not documented nest predation by mammals (P. Hodum in litt. 2020). Invasive mammals were further found to be vectors for seed dispersal of invasive plants (P. Hodum in litt. 2020). Cats have been documented killing firecrowns in town throughout the year (Hodum in litt. 2007, 2008, E. Hagen in litt. 2020). Austral Thrush Turdus falcklandii has been observed predating firecrown nests and may represent a threat (Hahn et al. 2011a). As is true with many island species, firecrowns are easily approached, thus rendering them highly susceptible to predation. Additionally, during its nocturnal torpor, this species is presumed to be very vulnerable to predation (Hahn and Römer 2002).

Males are able to defend territories with highly productive resources, but the smaller females are possibly being indirectly outcompeted by S. sephaniodes (Roy et al. 1999, Wolf 2008). Observations of interactions between the two species in 2006-2007 found no evidence that male fernandensis were negatively affected by S. sephaniodes, but that female fernandensis may suffer from interference competition and may be marginalised from high quality foraging habitat (Wolf and Hagen 2012). Abundance and diversity of aerial arthropods is higher in native than degraded forest, consistent with the argument that native forest provides higher-quality habitat for breeding (Hagen et al. 2010, P. Hodum in litt. 2020). S. sephaniodes prefers sites with denser vegetation, higher species diversity and nests less high off the ground, and therefore may not constrain nesting habitat use by S. fernandensis; alternatively competitive displacement for nest site choices may already have occurred (Hahn et al. 2011a). A study in 2016 found a negative association between the abundance of the two species in the post-breeding season, with individuals of both species tending to congregate in area where the other was less abundant, which suggests a high interspecific competition during this period (Vizentin-Bugoni et al. 2017).

Preliminary analyses of the population revealed some genetic variation, but significantly less than in S. sephaniodes (Roy et al. 1999). A devastating tsunami in February 2010, which destroyed the only town on Robinson Crusoe, may have contributed to reducing the population to 740 individuals in March 2011 (I. Hahn in litt. 2015). Seasonally important populations of the endemic Cabbage Tree (Dendroseris litoralis) in the coastal zone were lost as a result of the tsunami (Hahn et al. 2015). However, the disaster likely also reduced cat predation. Hurricane-force storms which hit the island in 2015 and 2016 significantly reduced the number of successful nests and decreased productivity, presumably due to direct loss of nests, loss of flowering resources and reductions in aerial arthropod populations (P. Hodum in litt. 2020).

Conservation actions

Conservation Actions Underway
CITES Appendix II. The Juan Fernández Islands were designated as a national park in 1935 (protected from 1967) and an UNESCO Biosphere Reserve in 1977. The Chilean government began restoring habitat in 1997 (J. C. Torres-Mura in litt. 1999), and the islands have been nominated for World Heritage listing (Hulm and Thorsell 1995). Conservation is being led by Oikonos (Oikonos, n. d.). Key activities which have already taken place are (Hodum and Rodriguez 2005, P. Hodum in litt. 2007, 2008): the hiring of two island residents as project coordinators; control of invasive plants and herbivores (including volunteer programmes for island residents to participate in invasive plant removal), which appears to increase nesting success of the species; invasive predator control (including cat control in the town on Robinson Crusoe); habitat restoration in native forest; a community outreach programme aimed at engaging local people (Anon. 2005) and including environmental education programmes for local schoolchildren; as well as population surveys and monitoring of active nests, phenology and reproductive success. The endemic plant Dendroseris litoralis has been planted in settlement areas to provide nectar resources for the species (Hahn et al. 2011b). The population has been monitored since 2006, and a workshop on terrestrial bird census techniques was organized for local people in October 2011, aimed at forming a local team that can carry out regular bird censuses; a pilot project was implemented to test the capacity of the trained team of local fieldworkers to gather data by using a monitoring protocol. Ongoing and planned work includes further invasive plant control, the planting of native plant species, carrying out environmental education workshops in the local high school and the development of a programme of cat control (Oikonos n.d., Mohamed bin Zayed Species Conservation Fund 2017). A national recovery strategy is being prepared by the Chilean Ministry of the Environment, assisted by Oikonos (P. Hodum in litt. 2020).

Conservation Actions Proposed
Continue to monitor the population using a quantitative census methodology that allows for statistical comparisons between surveys. Carry out mark-recapture studies to describe key demographic parameters needed for conservation management action (E. Hagen in litt. 2020). Investiage whether the competition between S. fernandensis and S. sephanoides during the non-breeding season impact densities of S. fernandensis (J. Vizentin-Bugoni in litt. 2020). Take measures to control S. sephanoides if negative impacts on S. fernandensis exist (J. Vizentin-Bugoni in litt. 2020). Survey additional areas of high-quality forest to determine if other areas of critical breeding habitat exist (P. Hodum in litt. 2020). Ensure that Cabbage Trees that were destroyed by the 2010 tsunami are replanted (Hahn et al. 2015). Enforce grazing restrictions on National Park land (Roy et al. 1999). Evaluate feasibility of establishing feeding stations in native forest. Continue to replant native plants that are critical food sources (including Sophora fernandeziana and Rhaphithamnus venustus), especially in watersheds far from San Juan Bautista where the highest densities of cats are concentrated (E. Hagen in litt. 2020, P. Hodum in litt. 2020). Continue to support ongoing efforts and expand them further to remove alien invasive plants and mammalian predators, and increase awareness. Investigate scale of predation risk from Austral Thrush and consider control measures if appropriate (Hahn et al. 2011a). Evaluate genetic variation and inbreeding depression within the population (Roy et al. 2013).

Identification

13 cm. Entirely rufous hummingbird. Male bright rufous-orange, with dusky flight feathers. Reddish-yellow crown, generally appearing dark. Dusky lores. Immature male has rufous spotting on crown. Female dark green above, with bluish tinge on crown. Whitish underparts, densely spotted dark green on throat, extending on to flanks. Similar spp. Female Green-backed Firecrown S. sephanoides is smaller, paler green with duskier underparts and not so densely spotted on throat, with white postocular spot.

Acknowledgements

Text account compilers
Wheatley, H., Hermes, C.

Contributors
Benstead, P., Bird, J., Butchart, S., Capper, D., Hagen, E., Hahn, I., Hodum, P., Khwaja, N., Sharpe, C.J., Symes, A., Torres-Mura, J.C. & Vizentin-Bugoni, J


Recommended citation
BirdLife International (2024) Species factsheet: Juan Fernandez Firecrown Sephanoides fernandensis. Downloaded from https://datazone.birdlife.org/species/factsheet/juan-fernandez-firecrown-sephanoides-fernandensis on 22/11/2024.
Recommended citation for factsheets for more than one species: BirdLife International (2024) IUCN Red List for birds. Downloaded from https://datazone.birdlife.org/species/search on 22/11/2024.