Data Zone
Justification of Red List category
This species is classified as Endangered since it has a very small population and range, within which habitat continues to be lost and degraded.
Population justification
Population estimates range from fewer than 100 pairs to 125-130 (Bretagnolle et al. 2000), 130-170 pairs (M. Le Corre in litt. 1999), and most recently 564 adults recorded in 2009-2010, including c.150 confirmed or probable pairs, with the total number perhaps higher (Grondin and Philippe 2011). This gives a range of 200-560 mature individuals.
Trend justification
The range seems to have been stable since the late 1970s (Bretagnolle et al. 2000), and the population was believed to be at least stable (V. Bretagnolle in litt. 2007) and probably increasing following the introduction of protection measures (Cheke 1987; M. Le Corre in litt. 2000; V. Bretagnolle in litt. 2007). Subsequent surveys found a decrease in population density in some areas between 2000 and 2010, however some areas were occupied in 2010 that were unoccupied in 2000 (Grondin and Philippe 2011). The overall trend is difficult to determine, but the species is suspected to have undergone a slow decline between 2000-2010.
Circus maillardi is confined to Réunion (to France). Current population estimates range from less than 100 pairs to 125-130 (Bretagnolle et al. 2000), 130-170 pairs (M. Le Corre in litt. 1999), and 150 confirmed or probable pairs (Grondin and Philippe 2011). A population of around 130 pairs probably equates to a total population close to or exceeding 500 individuals (V. Bretagnolle in litt. 2007), estimated by Grondin and Philippe (2011) at at least 564 individuals. The range appears to have been stable from the late 1970s to the present (Bretagnolle et al. 2000), and numbers were believed to be at least stable and probably increasing as a consequence of protection (Cheke 1987; M. Le Corre in litt. 2000; V. Bretagnolle in litt. 2007). However, a decrease in population density was observed in some areas between 2000 and 2010, while some areas were occupied in 2010 that were unoccupied in 2000, making the overall trend difficult to determine (Grondin and Philippe 2011). Most suitable habitat is occupied, albeit with varying densities (M. Le Corre in litt. 2000).
When breeding, it largely occupies indigenous and degraded forests (Clouet 1978; V. Bretagnolle in litt. 1999; M. Le Corre in litt. 1999) - although rarely tall, dense forest - mostly between 300 and 700 m. It forages in most habitats, but particularly in wooded and forested habitats (65%), as well as cultivated (sugarcane) fields and pastures (20%) and open grasslands and savannas (15%) (Bretagnolle et al. 2000). Its original diet was probably entirely birds and insects, but now c.50% consists of introduced mammals such as rats, mice and tenrec Tenrec ecaudatus (Clouet 1978). Reptiles, particularly Oriental garden lizard Calotes versicolor, are also commonly taken (V. Grondin in litt. 2012). It will also take carrion. Its fecundity is poor for a member of the Circus genus and is probably related to the lack of natural predators and low benefits of dispersion (Clouet 1978). The nest is built on the ground.
Poaching (M. Le Corre in litt. 1999) and persecution (it is believed to be a predator of chickens and, formerly at least, was considered a bird of ill omen) (Jakubek et al. 1997) continue, despite protective legislation, and together with secondary poisoning from rodenticides constitute the most serious current threats (Grondin and Philippe 2011). Poisoning from anticoagulant rodenticides is now suspected to be the most significant threat, with the number of birds potentially poisoned in this way dramatically increasing since 2014 (Coeurdassier et al. 2019). Increasing urbanisation and road construction bring disturbance further into the breeding habitat. Below 1,300 m, cultivation and urbanisation have eliminated native forest from all but the steepest of slopes. Cyclones, heavy rains and fires may possibly degrade remaining habitat (Bretagnolle et al. 2000) that is already increasingly degraded by exotic plants (Macdonald et al. 1991). Other possible threats include silvicultural management of some forests, collisions with electrical cables and wind turbines, and human hunting pressure on some prey species (e.g. larger birds) (Bretagnolle et al. 2000; Grondin and Philippe 2011).
Conservation Actions Underway
CITES Appendix II. It has been protected since 1966, with protection strengthened in 1974, leading to an increase in numbers (Cheke 1987), and is protected by a 1989 Ministerial Decree. Ongoing public awareness campaigns and conservation action aim to stop poaching and to rescue and release poached birds (M. Le Corre in litt. 1999). Between 1997-2009 103 individuals were taken into care, many in a critical condition, of which 43 were successfully released back into the wild (Grondin and Philippe 2011). Advice has been given on minimising secondary poisoning occurring as a result of rodent control. A Species Action Plan was published in 2011 (Grondin and Philippe 2011).
Conservation Actions Proposed
Monitor its population trends. Continue developing public awareness campaigns to stop poaching and persecution. Protect remaining habitat. Ensure that rodent control methods minimise the risk of secondary poisoning (M. Le Corre in litt. 1999; Grondin and Philippe 2011). Develop a strategy to decrease collisions with cables and wind turbines, and improve care of birds brought to SEOR care centre (V. Grondin in litt. 2012).
54 cm. Large harrier. Male has mainly black head and dark back, contrasting with light grey primaries/secondaries, unbarred tail, and white rump, belly, and underwings. Female and immature dark brown, with barred tail. Whitish rump at all ages. Voice Grating kiay kioo near breeding site, kai pi-pi-pi-pi-pi by male during display flights. Hints Search in forested habitat.
Text account compilers
Clark, J.
Contributors
Bretagnolle, V., Ekstrom, J., Grondin, V., Le Corre, M., Pilgrim, J., Safford, R., Stattersfield, A., Symes, A., Taylor, J., Thiollay, J.-M. & Westrip, J.R.S.
Recommended citation
BirdLife International (2024) Species factsheet: Reunion Marsh-harrier Circus maillardi. Downloaded from
https://datazone.birdlife.org/species/factsheet/reunion-marsh-harrier-circus-maillardi 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.