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). 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 extremely 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 global population is estimated to number c.2,900,000-6,200,000 individuals (Wetlands International 2014). However if the most recent estimate of the European population is included (909,000-1,440,000 pairs, which equates to 1,820,000-2,870,000 mature individuals or 2,730,000-4,305,000 individuals) the updated estimate is 4,956,000-8,400,000 individuals. The population is therefore placed in the band 5,000,000-9,999,999 individuals.
The overall population trend is thought to be stable, although some populations are decreasing, while others are increasing, stable or have unknown trends (Wetlands International 2014). The European population is estimated to be stable (BirdLife International 2015).
Behaviour This species is predominantly sedentary or locally dispersive, but makes partially or fully migratory movements in the northern parts of its range due to its vulnerability to freezing conditions (Taylor and van Perlo 1998). Most northern populations move south from September to December, returning again from March to May (del Hoyo et al. 1996). The species breeds in solitary territorial pairs during the spring, especially during wet months (the exact timing varying geographically) (del Hoyo et al. 1996). It remains largely solitary throughout the year although juveniles and adults may form diurnal feeding groups of up to 30 individuals in the winter, especially during hard weather (Taylor and van Perlo 1998), often congregating on sheltered lakes and ponds (del Hoyo et al. 1996).
Habitat The species inhabits freshwater wetlands, both still and moving, requiring easy access to open water (del Hoyo et al. 1996) and showing a preference for waters sheltered by woodland, bushes or tall emergent vegetation (del Hoyo et al. 1996, Taylor and van Perlo 1998). Suitable habitats include slow-flowing rivers (del Hoyo et al. 1996, Taylor and van Perlo 1998), oxbow lakes (Taylor and van Perlo 1998), streams, canals, ditches, lakes, reservoirs, sites with small open water surfaces such as pools and ponds only a few metres across, swamps, marshes (del Hoyo et al. 1996, Taylor and van Perlo 1998), seasonally flooded sites (del Hoyo et al. 1996) such as flood-plains (Taylor and van Perlo 1998), disused gravel pits, rice-fields (del Hoyo et al. 1996, Taylor and van Perlo 1998), sewage ponds (Taylor and van Perlo 1998), and occasionally seashores (Azerbaijan) (Taylor and van Perlo 1998). It generally avoids very open sites (especially those exposed to wind or wave action) (del Hoyo et al. 1996, Taylor and van Perlo 1998) and oligotrophic or saline habitats (although it may be found on brackish waters) (del Hoyo et al. 1996, Taylor and van Perlo 1998). When foraging the species may range onto drier grassland, agricultural land or meadows, and on migration and in the winter months it can often be observed on damp grassland away from water (Taylor and van Perlo 1998).
Diet The species is omnivorous and opportunistic, its diet consisting of earthworms, crustaceans, molluscs, adult and larval insects (especially flies, mayflies, caddisflies, bugs, beetles and Lepidoptera), spiders, small fish, tadpoles and occasionally birds eggs, as well as plant matter such as filamentous algae, moss, the vegetative parts of reeds and aquatic plants, the seeds of reeds, rushes, sedges, water-lilies, waterside herbaceous vegetation, trees (Ulmus spp.) and cereal crops, flowers of Eichhornia spp., and the berries and fruits of yew, Rubus, Sorbus, Rosa, Crataegus, Rhamnus, Hedera, Sambucus, Hippophae spp. and various orchard trees (del Hoyo et al. 1996).
Breeding site The nest varies between a shallow saucer and a deep cup constructed from twigs and waterside vegetation, and can be floating on or positioned up to 1 m above water in emergent vegetation, or positioned on a solid platform of branches in water. Less often the nest is placed in ground vegetation or in low bushes on the bank near water, or in bushes and trees up to 8 m from the ground (del Hoyo et al. 1996).
Management information Early harvesting in rice-fields should be avoided as it harms nests and young broods of this species (Taylor and van Perlo 1998).
In north-west Europe, populations are known to fluctuate significantly owing to severe winters (Taylor et al. 2014). The species is susceptible to avian influenza (Melville and Shortridge 2006, Gaidet et al. 2007) and avian botulism (Rocke 2006) and may be threatened by future outbreaks of these diseases. It is also vulnerable to predation by introduced American Mink (Neovison vison) in the U.K. (Ferraras and McDonald 1999).
Conservation Actions Underway
EU Birds Directive Annex II. There are currently no known conservation measures for this species in Europe.
Conservation Actions Proposed
The following information refers to the species's European range only: Wetland expansion for other species is likely to benefit this species. In areas where American Mink are present, predator control may be needed.
Text account compilers
Ashpole, J, Butchart, S., Malpas, L., Symes, A., Ekstrom, J., Taylor, J.
BirdLife International (2023) Species factsheet: Gallinula chloropus. Downloaded from http://datazone.birdlife.org/species/factsheet/common-moorhen-gallinula-chloropus on 05/06/2023. Recommended citation for factsheets for more than one species: BirdLife International (2023) IUCN Red List for birds. Downloaded from http://datazone.birdlife.org on 05/06/2023.