EN
Madagascar Marsh-harrier Circus macrosceles



Justification

Justification of Red List Category
This species has been uplisted to Endangered as it has a very small population, which is likely to be declining owing to a variety of threats, principally habitat loss and degradation, and persecution by humans.

Population justification
Surveys in 2005-2006 of 71% of the potential harrier habitat in Madagascar recorded a total of 80 individuals. The population on Comoros (three separate subpopulations on Grande Comore, Moheli and Anjouan), where its habitat is nearly totally destroyed, is estimated at no more than 50 mature individuals (R. Thorstrom and L.-A. Rene de Roland in litt. 2007). The total population is here estimated to be less than 250 mature individuals (R. Thorstrom in litt. 2016), placed in the range of 100-249 mature individuals.

Trend justification
The population is suspected to be in moderate decline on the basis of the loss and degradation of breeding habitat, persecution and disturbance.

Distribution and population

Circus macrosceles is confined to the Madagascar and the Comoro Islands. It has not been seen recently on Mayotte (to France) (Safford 2001). The species has a broad distribution stretching c.1,000 km from north to south on Madagascar, but occurs at very low densities; surveys in 2005-2006 of 71 % of the potential harrier habitat on the island recorded a total of 80 individuals (Rene de Roland et al. 2009). The population on Comoros (Grande Comore, Moheli and Anjouan: three separate subpopulations), where its habitat is nearly totally destroyed, is estimated at no more than 50 mature individuals (R. Thorstrom and L.-A. Rene de Roland in litt. 2007). The total population was estimated to be somewhere in the range 250-500 mature individuals, but it is now likely less than 250 mature individuals (R. Thorstrom in litt. 2016). The Bealanana and Ankozobe regions in Madagascar are particularly important breeding sites for the species (Rene de Roland et al. 2009). It is suspected to be declining, but population trends have not yet been accurately quantified.

Ecology

In Madagascar, it is primarily associated with wetlands, hunting around the periphery of vegetation-fringed lakes, marshes, coastal wetlands and rice-paddies, as well as over savanna grasslands (Langrand 1990), including those that are very degraded (R. Safford in litt. 1999). On the Comoros, it uses a variety of open and forested habitats in drier areas. It feeds on small vertebrates (including birds) and insects (Langrand 1990, Morris and Hawkins 1998). It nests in low vegetation or on the ground in marshes (Morris and Hawkins 1998, Rene de Roland et al. 2004, 2009). Breeding has been recorded as starting in late August and September, during the middle of the dry season (Rene de Roland et al. 2004). The incubation period has been observed to be 32-34 days, and nestlings fledge at 42-45 days of age at the start of the rainy season. The species reproduces at a relatively low rate, with mean clutch size recorded as 2.9 eggs, average productivity recorded as 0.9 young fledged per breeding attempt, and three quarters of nesting attempts were successful. The diet is comprised of insects, snakes, birds, lizards, rodents and domestic chickens (Rene de Roland et al. 2004).

Threats

In Madagascar, this species is likely to have very poor nesting success owing to the regular and comprehensive burning of grasslands and marshes, especially in the central high-plateau region (to produce fresh grazing areas and to clear land) (Rene de Roland et al. 2004, 2009, Anon. 2007), and due to egg-hunting and nest-destruction by local people (ZICOMA 1999, A. F. A. Hawkins in litt. 2000). Most savannah fires occur from August to November, thus coinciding with the species's breeding season (Rene de Roland et al. 2009). For example, in October 2005, all seven nests at Ambohitantely were destroyed by fire during the incubation period, resulting in the loss of all eggs (L-. A. Rene de Roland in litt. 2006, Rene de Roland et al. 2009.). Conversion of wetlands for rice farming is also likely to have a negative impact upon the species (Rene de Roland et al. 2004, 2009, L.-A. Rene de Roland in litt. 2006, Anon. 2007). Over 80% of marshland in Madagascar has been converted into rice fields (R. Thorstrom and L.-A. Rene de Roland in litt. 2007), mainly in areas of dense human inhabitation (Rene de Roland et al. 2009). Nestlings are often taken by people for food, and interviews with local communities have revealed that adults are also hunted for food (Anon. 2007, Rene de Roland et al. 2009). The species is also persecuted because of its threat to poultry, however, in one study of breeding birds, domestic chickens accounted for only 1% of prey items (Rene de Roland et al. 2004). The disturbance of marshes appears to limit the number of breeding pairs present, and human activities during the cultivation period may force the movement of birds. The species requires undisturbed areas with unaltered savannah, however land-use activities have rendered it absent from many areas of Madagascar (Rene de Roland et al. 2009).

Conservation actions

Conservation Actions Underway
CITES Appendix II. It has been recorded from a number of protected areas, including five National Parks, one Strict Reserve, one Special Reserve, one Classified Forest and one Hunting Reserve (ZICOMA 1999). However, the protection of the marshes and grasslands that are vital for the species is relatively neglected compared with the protection of forest in Madagascar (Rene de Roland et al. 2004, 2009). The species is the subject of research into its population (Rene de Roland et al. 2009, L.- A. Rene de Roland in litt. 2006, Anon. 2007) and breeding biology (Rene de Roland et al. 2004).

Conservation Actions Proposed
Carry out further surveys to confirm the total population size. Study the species's population dynamics (Rene de Roland et al. 2004). Obtain more accurate estimates of nesting success, and investigate relative importance of different mortality factors at nest. Reduce burning at key sites, particularly during the breeding season when fires destroy nests. Identify and establish protected areas to conserve key nesting sites. Improve protection of marshes and grasslands (Rene de Roland et al. 2009). Raise awareness amongst local communities about the impacts of fire (Rene de Roland et al. 2009). Study the species's ecology on Comoros (Rene de Roland et al. 2009).

Identification

59 cm. Large harrier. Male blackish on forewing, primaries and mantle, greyer on head, tail and secondaries, with blackish streaks on head and throat. Rump whitish, as in female, which is browner overall with conspicuous bars underneath primaries and on tail. Similar spp. Differs from Black Kite Milvus migrans, Madagascar Buzzard Buteo brachypterus and Madagascar Harrier-hawk Polyboroides radiatus by rather long, narrow wings, white rump, habit of flying low with wings in a V and, in male, by contrasting wing pattern.

Acknowledgements

Text account compilers
Bird, J., Butchart, S., Ekstrom, J., Evans, M., Symes, A., Taylor, J. & Westrip, J.

Contributors
Hawkins, F., Rabarisoa, R., Rene de Roland, L., Safford, R. & Thorstrom, R.


Recommended citation
BirdLife International (2021) Species factsheet: Circus macrosceles. Downloaded from http://www.birdlife.org on 08/03/2021. Recommended citation for factsheets for more than one species: BirdLife International (2021) IUCN Red List for birds. Downloaded from http://www.birdlife.org on 08/03/2021.