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Juan Fernandez Tit-tyrant Anairetes fernandezianus



Justification

Justification of Red List category
This species is restricted to a single island. Habitat loss and degradation through invasive plants and predation by introduced species are causing rapid declines, so that the population is now very small. It is consequently listed as Endangered.

Population justification
Estimated at 5,000 individuals during the mid-1980s (Brooke 1987), the population appears to have undergone a rapid decline since. While census data suggested a population of 4,200 individuals in 1994, it declined to 2,000 individuals in 2001 and to 1,550 individuals in 2009 (Hahn et al. 2011). Under the assumption that declines are continuing at this rate to the present day, the current population is thought to number 780 individuals, which equates to 520 mature individuals.
The population size is here placed in the band 250-1,550 mature individuals, with a best estimate of 520 mature individuals. This wide band reflects the uncertainty in the current estimate and the absence of recent population and trend data; the minimum population size is set as 250 mature individuals under the assumption that declines may have accelerated, while the maximum is set as 1,550 mature individuals under the assumption that the population has remained stable since 2009.

Trend justification
In the mid-1980s the population was estimated to be stable and secure at 5,000 individuals (Brooke 1987). Since then, the species however appears to have suffered from habitat loss through land-use change and the spread of invasive plants, as well as from predation by birds and introduced mammals (Hahn et al. 2011). While the population numbered around 4,200 individuals in 1994, it dropped to 2,000 individuals in 2001 and further to 1,550 in 2009 following an exponential decline (Hahn et al. 2011).
There is no recent data on the population trend. However, under the assumption that the population continued to decline exponentially to the present day, the rate of decline amounts to 39% over the past ten years.
There are currently considerable efforts being undertaken to restore native vegetation and to eradicate introduced predators (Dittrich 2019); this may prove beneficial to the species and it is therefore likely that the rate of decline will slow down in the near future. Precautionarily, it is however inferred that population declines will go on at a similar rate into the near future, here placed in the band 30-39% over ten years.

Distribution and population

Anairetes fernandezianus is endemic to Isla Robinson Crusoe in the Juan Fernández Islands, Chile.

Ecology

It is found in all wooded habitats on the island, from undisturbed forest, luma Nothomyrica fernandeziana parkland, Eucalyptus woodland, to degraded, disturbed or invasive vegetation and gardens (Brooke 1987, Fitzpatrick 2020). It however appears to show a strong preference for native montane forests and lowland scrub, whereas it is considerably less common in non-native scrub, cultivated land and near settlements (Hahn et al. 2005, 2011; Soto et al. 2013). It feeds on insects (Fitzpatrick 2020). It presumably breeds between October and December, with nests being placed in dense canopy or mid-layer of trees (Hahn 2006).

Threats

The species is threatened by the degradation and replacement of native vegetation through non-native plants and grazing by introduced goats and cattle (Hahn et al. 2011, Shirihai et al. 2015). Further threats include predation by introduced Red-backed Hawk (Geranoaetus polyosoma) from Isla Alejandro Selkirk, rats (Rattus spp.) and cats (Felis catus) (Hahn and Römer 2002, Shirihai et al. 2015).
Habitat degradation and conversion has been severe in the past, with native vegetation remaining mostly only on steep hillsides (Roy et al. 1999). Forest loss has however slowed down considerably since, so that it was considered negligible in 2011 (Hahn et al. 2011), and efforts to restore native vegetation and eradicate invasive species are ongoing (Vargas et al. 2013, Dittrich 2019).

Conservation actions

Conservation Actions Underway
The entire population is protected in the the Juan Fernández Archipelago National Park. In 1994, the islands were nominated for UNESCO World Heritage listing. The Chilean government began a habitat restoration programme in 1997, which involves the conservation and restoration of native vegetation and the eradication of introduced species (J. C. Torres-Mura in litt. 1999, Dittrich 2019).

Conservation Actions Proposed
Confirm the population estimate through a comprehensive census. Regularly monitor the population to quantify the trend. Study the impacts of predation by introduced species.
Continue efforts to preserve and restore native vegetation. Continue efforts to remove alien species.

Identification

13 cm. Small streaky flycatcher. Ashy-grey upperparts. Black head and long spiny crest feathers, with some white streaking. Whitish underparts heavily streaked black. Female has shorter crest. Voice Not reported. Hints Conspicuous at woodland edges.

Acknowledgements

Text account compilers
Hermes, C.

Contributors
Capper, D., O'Brien, A., Sharpe, C.J. & Torres-Mura, J.C.


Recommended citation
BirdLife International (2024) Species factsheet: Juan Fernandez Tit-tyrant Anairetes fernandezianus. Downloaded from https://datazone.birdlife.org/species/factsheet/juan-fernandez-tit-tyrant-anairetes-fernandezianus 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.