• Summary
• Text account
• Data table and detailed info
• Distribution map
• Reference and further resources

Justification of Red List category
This species is experiencing an ongoing decline in population size, and has disappeared from a large part of its range. It is listed as Endangered on the basis that it has a very small and declining population, which occupies a very small range in which habitat quality is in decline owing to the spread of introduced plant species, and the presence of introduced predators. The number of locations for this species is also very small.

Population justification
The species underwent a spectacular recovery from just four wild birds in 1974 (Safford and Jones 1997) to a probable peak of 350-500 individuals at the end of the 1990s (C. Jones in litt. 2012, Jones et al. 2013), thanks to a successful restoration programme that took place between 1973 and 1994, and subsequent monitoring (e.g. Nicoll et al. 2004, Nicoll et al. 2021). However, since the late 2000s, a continuing decline has been observed, and most recently Nicoll et al. (2021) estimates the population in 2018 at less than 250 individuals, i.e. less than 170 mature individuals. Considering total the number of pairs monitored over all subpopulations, it is likely that the population minimum is c.73 pairs, therefore it is considered that the population is between 140 and 170 mature individuals. The species is currently considered to be divided into three discrete subpopulations (with the fourth subpopulation in the north of the island extinct since 2007), with no interchange between the subpopulations (Nevoux et al. 2013, Nicoll et al. 2021).

Trend justification
The peak population size is likely to have occurred at the end of the 1990s, at 350-500 individuals and 99 breeding pairs (Cade 2008, C. Jones in litt. 2012, Jones et al. 2013). Past estimates showed a population size of 800-1,000 individuals by the start of the 2005-2006 breeding season (Burgess et al. 2009; V. Tatayah in litt. 2006), but it is now thought unlikely that the population was ever actually close to reaching 1,000 individuals (V. Tatayah in litt. 2012). In 2007-2008, the population was estimated at 500-600 individuals but with only 88 breeding pairs (Cade 2008, Dale 2008), and in 2011-2012, the total population was estimated at c. 300-400 birds (V. Tatayah in litt. 2012). The current population is estimated to be less than 250 individuals overall (Nicoll et al. 2021). 
Declines have been observed in the western subpopulation, particularly in suboptimal habitat on the periphery of its range, since 2007-2008, with 30 pairs monitored in 2012 (three generations ago) (V. Tatayah in litt. 2012, Jones et al. 2013, Nicoll et al. 2021). In 2016, approximately 20 pairs were monitored in this subpopulation, with this number going down to below 15 by 2018. The eastern population has grown and stabilised since 2008 at over 50 pairs, whereas that in the southern subpopulation is relatively stable but with eight pairs or less (Nicoll et al. 2021). With two subpopulations stable and one decreasing (Nicoll et al. 2021), the species is therefore estimated to have declined by approximately 26% over the past three generations (and therefore placed in the band of 25-29% past reduction), 24% between 2013 and 2024 (and therefore placed in the band 20-24% past and future reduction) and projected to decline by approximately 10% over the next three generations (and therefore placed in the band 5-15% future reduction).

The species is restricted to Mauritius, and has undergone a recovery in range after successful reintroductions, from just very small remnant population in the Black River Gorge in 1974 (Safford and Jones 1997, Nicoll et al. 2021) to four discrete subpopulations across the island by the end of the 1994 breeding season (Nicoll et al. 2004, Nicoll et al. 2021). These were located on mountain chains in the north, east and south-west of Mauritius, the latter holding two subpopulations (hereafter referred to as the southern and the western sub-populations) (Jones and Swinnerton 1997, Nicoll et al. 2021, Tatayah 2022).
However, by 2007, the small sub-population in the Moka Range in the north of the island, which most likely never held more than three breeding pairs, had gone extinct (V. Tatayah in litt. 2012, Jones et al. 2013, Nicoll et al. 2021), with this area badly affected by exotic plant species (Cade 2008, Dale 2008). This has reduced the species' EOO considerably, from 880 km² (BirdLife International 2016) to 540km² (this study), and reduced its number of subpopulations to three (Tatayah 2022). There is no record of dispersal to other locations despite intensive monitoring through colour ringing (Ewing et al. 2008, Senapathi et al. 2011), and it is considered unlikely that there is any interchange between the subpopulations (Nevoux et al. 2013, Nicoll et al. 2021). The species' AOO is now considered to measure a maximum of 316 km² (this study).
Since 2007, declines have also been observed in the western population (Nicoll et al. 2021), particularly in suboptimal habitat on the periphery of its range (V. Tatayah in litt. 2012, Jones et al. 2013). The eastern population has grown and stabilised, whereas the southern population is did not grow much before stabilising (Nicoll et al. 2021).

Its primary habitat was native, evergreen, subtropical forests, which now only remain in the south-west of the island, but captive-bred birds have shown greater tolerance for degraded and open areas, such as secondary forest and shrubland (Jones 1998, Carter and Jones 1999, Kemp et al. 2020). These types of habitats may however be sinks, with a higher risk of predation and disease and lower food resources and productivity (Burgess et al. 2011, Jones et al. 2013). Avoidance of agricultural areas may be partly due to a lack of isolated mature trees to use as vantage points (Burgess et al. 2009). It preys mainly on endemic arboreal Phelsuma day-geckos, as well as other reptiles, but can take small birds, insects, and introduced shrews and juvenile rats too (Temple 1977, Jones 1987, Jones et al. 2013, Kemp et al. 2020). A territorial species, pairs may stay together for several years, with divorce occurring after failed breeding (Jones et al. 2013). It traditionally nests in volcanic rock-cavities, and tree holes, within forest territories (Temple 1977, Jones 1987, Jones et al. 2013). Clutches usually contain 3-4 eggs, but may range between 1 and 5 (Jones et al. 2013).

Deforestation by early colonists initiated declines, with less than 2% of original forest now remaining (Tatayah 2022). More recent declines appear related to organochloride pesticide-use in the 1950s and 1960s in agriculture and to control malaria-carrying mosquitoes (Cheke 1987a, Safford and Jones 1997). 
The main current threats to the species are: introduced plants, including Traveller's Palm Ravenala madagascariensis, Strawberry Guava Psidium cattleianum, Ligustrum robustum and the liana Hiptage benghalensis, all of which have invaded much of the species' habitat, particularly in the north of the island (Burgess et al. 2009, Cade 2008), which reduce the kestrel's hunting efficiency, or even can render hunting below the canopy impossible, as well as reducing the density of day-geckos (Cade 2008, Jones et al. 2013); and introduced predators, including Black Rats Rattus rattus, Crab-eating Macaques Macaca fascicularis, Javan Mongooses Herpestes javanicus and feral cats Felis catus which prey on eggs, young or adults (Cade and Jones 1993, C. Jones in litt. 2000), and reduce the availability and quality of the natural nesting sites they can access (Jones et al. 2013). 
In addition, birds in suboptimal habitat in the west have been lost when natural nest sites are absent (e.g. loss of trees with suitable cavities, or deterioration of nesting sites) (V. Tatayah in litt. 2012) and due to the small choice in suitable habitat left for the species on the island overall, competition for nesting sites may occur with White-tailed Tropicbirds Phaethon lepturus, and introduced feral pigeons, Common Mynas Acridotheres tristis and Black Rats (Jones et al. 2013). The quality of natural nesting sites has therefore deteriorated, and the species has also suffered an extreme loss of genetic variation and high rates of inbreeding due to the population bottleneck, which are considered sufficient to affect the long-term viability of the population (Ewing et al. 2008). Because of this inbreeding, it is possible that the species may be particularly prone to infectious diseases, and it has contracted adenovirus when in captivity in the past (Forbes et al. 1997), and is very susceptible to trichomonosis (Jones et al. 2013). Climate change may be affecting the species through the increase in wet days at the start of the breeding season leading to increasingly later laying dates (Senapathi et al. 2011).

Conservation Actions Underway
CITES Appendix I and II. A recovery programme, at first concentrating on research, was initiated in 1973 (Nicoll et al. 2004). From 1984 to 1994, an intensive management programme significantly increased population numbers. Activities included captive propagation and restocking, supplementary feeding, nest-site enhancement, provision of nest boxes, nest guarding, control of predators around nest- and release-sites, clutch manipulations, brood manipulations, treatment of parasite infestations on chicks and the rescue of eggs/young from failing nests (C. Jones in litt. 2000, Jones et al. 2013). Release sites included the Bambous and Moka Mountain ranges and the Bel Ombre region. 
Since 1994, there has been no release of captive-bred birds (Jones 1998) and little active conservation management (Jones and Swinnerton 1997), although provision of nest-boxes and monitoring of survival and productivity continue. Research is on-going into genetic variation so that populations can be managed to preserve genetic diversity (Jones and Swinnerton 1997, Groombridge et al. 2000, Groombridge et al. 2001, Ewing et al. 2008). In October 2005, it was announced that plans for the construction of a highway through the east coast mountains IBA had been cancelled, with a different route to be used (Anon. 2006). The construction of the highway would have damaged the south-eastern forest, home to about half the species' world population, centred around Ferney Valley, which has now become a conservation area (Anon. 2006, V. Tatayah in litt. 2012). Long-term monitoring has shown that the species clutch size is higher in artificial nest boxes than in natural sites (Nicoll et al. 2021).

Conservation Actions Proposed
Continue and increase detailed and systematic population monitoring and ecological studies (C. Jones in litt. 2000, Nicoll et al. 2021), particularly using molecular techniques to monitor population size (Groombridge et al. 2001). There are no plans to introduce the species to islands outside of Mauritius (Tatayah 2022). Restart captive breeding and reintroduction, particularly between subpopulations to improve genetic diversity (Jones et al. 2013). Continue and expand provision of improved long-lasting nest boxes, particularly in the western population where natural nesting sites are lacking and scale-up nest site management, all which may be more effective than reintroductions / reinforcement (Jones et al. 2013, Nicoll et al. 2021).

Considering the overall habitat now available to the species on the island, it is likely that the carrying capacity of Mauritius will be below 1,000 individuals and therefore the population will probably always remain quite small (Jones et al. 2013), but it is hoped that by continuing and increasing conservation measures, the species population will be functional in the long-term (Tatayah 2022).

20-26 cm. Small, chestnut-and-white falcon. Male noticeably smaller than female. Rich warm brown to chestnut upperparts, with black crescentic markings on wings and mantle. Gleaming white underparts with bold, black heart-shaped blotchings. In flight, wings relatively rounded and long, thin tail. Voice Repeated toee tooee or shorter tooit tooit.

Text account compilers
Symes, A., Martin, R., Westrip, J.R.S., Rutherford, C.A.

Contributors
Jones, C.G. & Tatayah, V.

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Recommended citation
BirdLife International (2024) Species factsheet: Mauritius Kestrel Falco punctatus. Downloaded from https://datazone.birdlife.org/species/factsheet/mauritius-kestrel-falco-punctatus on 23/11/2024.
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 23/11/2024.