Justification of Red List Category
This species has an extremely large range, and hence does not approach the thresholds for Vulnerable under the range size criterion (Extent of Occurrence <20,000 km2 combined with a declining or fluctuating range size, habitat extent/quality, or population size and a small number of locations or severe fragmentation). Despite the fact that the population trend appears to be decreasing, the decline is not believed to be sufficiently rapid to approach the thresholds for Vulnerable under the population trend criterion (>30% decline over ten years or three generations). The population size may be moderately small to large, but it is not believed to approach the thresholds for Vulnerable under the population size criterion (<10,000 mature individuals with a continuing decline estimated to be >10% in ten years or three generations, or with a specified population structure). For these reasons the species is evaluated as Least Concern.
The population is suspected to be in decline owing to ongoing habitat destruction and modification (del Hoyo et al. 1996).
Behaviour This species is an intra-African migrant (del Hoyo et al. 1996, Taylor and van Perlo 1998). At the onset of the rains populations in the northern tropics move north and populations in the southern tropics move south (del Hoyo et al. 1996, Taylor and van Perlo 1998), although some may remain sedentary all year round in permanent wetlands (del Hoyo et al. 1996). The timing of the breeding season varies geographically (del Hoyo et al. 1996) in relation to seasonal rainfall (Taylor and van Perlo 1998), the species breeding in territorial solitary pairs (del Hoyo et al. 1996) with nests well spaced even when many pairs share the same area (Taylor and van Perlo 1998). In favourable conditions the species may occur at high densities and in very large numbers (Taylor and van Perlo 1998), although it is more commonly found alone, in pairs, or in family groups (Langrand 1990, del Hoyo et al. 1996). The species undergoes a flightless moulting period shortly after breeding (Taylor and van Perlo 1998), and is mainly diurnal (Taylor and van Perlo 1998), being most active in the early-morning and late-afternoon (del Hoyo et al. 1996). Habitat The species shows a preference for wetlands with water-lilies and other floating vegetation (Urban et al. 1986) (such as Nymphaea, Nymphoides and Ottelia) (del Hoyo et al. 1996), and frequently occupies and breeds in seasonal or temporary habitats (Taylor and van Perlo 1998). Suitable habitats include freshwater marshes, inundated grasslands, flood-plains (del Hoyo et al. 1996) and river deltas (e.g. Okavango Delta) (Taylor and van Perlo 1998) with grasses and sedges (e.g. Oryza longistaminata and Cyperus fastigiatus), reedbeds, papyrus swamps, rice-fields, and thick vegetation (sedges, grasses and reeds) beside lakes, rivers, ponds and temporary pools (del Hoyo et al. 1996). Diet The species is omnivorous, its diet consisting of the flowers and seeds of reeds and sedges, the seeds, stems and leaves of grasses and other marsh plants, unripe seedheads of water-lilies, and fruits of thorn bush Drepanocarpus lunatus, as well as earthworms, molluscs, crustaceans, aquatic and terrestrial insects, spiders, fish eggs and small fish (Urban et al. 1986, del Hoyo et al. 1996, Hockey et al. 2005). Breeding site The nest is a loose structure of reeds, sedges and other vegetation typically positioned in reeds, grasses or tangled vegetation at the waters edge (Urban et al. 1986, del Hoyo et al. 1996, Hockey et al. 2005), and also in open marshes and rice-fields (Urban et al. 1986, del Hoyo et al. 1996).
The species is threatened throughout its range by the destruction and modification of wetlands (especially the loss of seasonally flooded habitats) through drainage, damming and grazing (del Hoyo et al. 1996). Utilisation The species is hunted for local consumption and trade at Lake Chilwa, Malawi (Bhima 2006).
Text account compilers
Ekstrom, J., Butchart, S., Malpas, L.
BirdLife International (2019) Species factsheet: Porphyrio alleni. Downloaded from http://www.birdlife.org on 18/11/2019. Recommended citation for factsheets for more than one species: BirdLife International (2019) IUCN Red List for birds. Downloaded from http://www.birdlife.org on 18/11/2019.