Data Zone
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 under 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). 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 (under 10,000 mature individuals with a continuing decline estimated to be over 10% in ten years or three generations, or with a specified population structure). The population trend appears to be increasing, and hence the species does not approach the thresholds for Vulnerable under the population trend criterion (over 30% decline over ten years or three generations). For these reasons the species is evaluated as Least Concern.
Population justification
The global population size is estimated at 25,000-100,000 individuals (Wetlands International 2023), which equates to 16,700-66,700 mature individuals. The overall population trend is suspected to be increasing over three generations (14.4 years) (Wetlands International 2023).
Trend justification
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Behaviour The movements of this species are little known (Hockey et al. 2005, Kushlan and Hancock 2005), although it is thought to be sedentary, sometimes making local movements in response to seasonal rainfall and the appearance of temporary shallow-water feeding areas (Hancock and Kushlan 1984, del Hoyo et al. 1992, Hockey et al. 2005, Kushlan and Hancock 2005). The species breeds at the start of the rainy season and in periods of flooding when shallow feeding sites develop (del Hoyo et al. 1992, Kushlan and Hancock 2005). It typically breeds in densities of 5 to 50 or up to 100 nests scattered throughout a single- or mixed-species colony. Exceptionally larger breeding colonies are observed, for example 1,500 nests were recorded at Chagana, Tanzania, and huge monospecific colonies used to form in Madagascar (over 10,000 birds where recorded at Antananarivo in 1949/50) although this no longer seems to occur (del Hoyo et al. 1992). When feeding the species may remain solitary and defend territories, or it may form feeding flocks of 5-50 individuals or more (Brown et al 1982, del Hoyo et al. 1992, Hockey et al. 2005) (a flock of 250 was recorded at Benamba Lake, Madagascar) (del Hoyo et al. 1992). It feeds diurnally (Brown et al 1982, del Hoyo et al. 1992), particularly at dusk (del Hoyo et al. 1992), and roosts communally in trees or reedbeds in both monospecific and mixed-species groups (Hockey et al. 2005). Habitat The species mainly inhabits lowlands, but occurs up to 1,500 m in the High Plateau Region of Madagascar (del Hoyo et al. 1992). It shows a preference for shallow, perennial (Hockey et al. 2005) freshwater habitats (del Hoyo et al. 1992) such as shallow lakesides (Brown et al 1982, del Hoyo et al. 1992, Hockey et al. 2005), dams (Hockey et al. 2005), ponds, flood-plains, rice-paddies (del Hoyo et al. 1992), marshes (del Hoyo et al. 1992, Hockey et al. 2005), swamps (Brown et al 1982), seasonally flooded grasslands and the edges of rivers (Brown et al 1982, Hockey et al. 2005). It can also found on alkaline lakes (del Hoyo et al. 1992) and in estuarine waters (Hockey et al. 2005) including mangroves, tidal mudflats (Brown et al 1982, del Hoyo et al. 1992, Hockey et al. 2005) and tidal creeks (Hancock and Kushlan 1984), although when in such habitats it remains near freshwater inlets (Brown et al 1982). Diet The diet of this species consists predominantly of fish, but crustaceans and aquatic insects are also taken (Brown et al 1982, del Hoyo et al. 1992, Kushlan and Hancock 2005). Breeding site The nest is a solid platform constructed of sticks and twigs, usually between 1 and 6 m (Brown et al 1982) high in trees, bushes or reedbeds, and always near or over water (del Hoyo et al. 1992, Kushlan and Hancock 2005).
The greatest threats to this species in Africa are human disturbance and avian predation at nest sites, as well as threats to the aquatic habitats on which the species depends (Kushlan and Hancock 2005). It is highly threatened in Madagascar due to human interference at breeding sites (del Hoyo et al. 1992, Kushlan and Hancock 2005).
Text account compilers
Rutherford, C.A.
Recommended citation
BirdLife International (2024) Species factsheet: Black Heron Egretta ardesiaca. Downloaded from
https://datazone.birdlife.org/species/factsheet/black-heron-egretta-ardesiaca on 23/12/2024.
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 23/12/2024.