Justification of Red List Category
This species has a very 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). The population trend appears to be stable, and hence the species does not approach the thresholds for Vulnerable under the population trend criterion (>30% decline over ten years or three generations). The population size is very large, and hence does not 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 stable in the absence of evidence for any declines or substantial threats (del Hoyo et al. 1996).
Behaviour Many individuals migrate southwards between August and November and return northwards between March and April, although over much of its range the species is present in fluctuating numbers throughout the year (Hayman et al. 1986). It breeds from April to August in dense colonies (Hayman et al. 1986), nesting in burrows set close together (del Hoyo et al. 1996) in sandy islets or dunes (Hayman et al. 1986). The species usually feeds singly or in loose groups, flocks occasionally foraging together on mudflats or in shallow water (del Hoyo et al. 1996) and gathering at communal high-tide roost sites (Hayman et al. 1986). Most of the species's activities occur in the early morning and late afternoon (del Hoyo et al. 1996). Habitat The species inhabits sandy coastlines and islands, intertidal sandflats and mudflats, estuaries, lagoons and exposed coral reefs (del Hoyo et al. 1996), specifically requiring sandy islands or extensive dunes up to 1 km inland in which to excavate nesting burrows (Hayman et al. 1986). Diet Its diet consists predominantly of crabs as well as other crustaceans, small molluscs and marine worms (del Hoyo et al. 1996). Breeding site The nest is an unlined chamber at the end of a burrow 100-250 cm long excavated into the sandy substrate (del Hoyo et al. 1996) of an island or extensive coastal dune system (Hayman et al. 1986). The species nests colonially, with many burrows set close together in a honeycomb arrangement (del Hoyo et al. 1996).
The species is threatened by future oil spills (del Hoyo et al. 1996, Hockey et al. 2005) and the potential introduction of nest predators onto breeding islands (del Hoyo et al. 1996). The planting of mangrove stands over bare substrates in some areas may also reduce the availability of nest sites (Hockey et al. 2005). Utilisation Eggs and young of the species used to be collected from nesting colonies, a practice which may still occur (Hockey et al. 2005).
Text account compilers
Butchart, S., Ekstrom, J., Malpas, L.
BirdLife International (2020) Species factsheet: Dromas ardeola. Downloaded from http://www.birdlife.org on 29/01/2020. Recommended citation for factsheets for more than one species: BirdLife International (2020) IUCN Red List for birds. Downloaded from http://www.birdlife.org on 29/01/2020.