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 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 global population is estimated at 107,000-1,011,000 individuals (Wetlands International 2016). The European population is estimated at 25-90 pairs, which equates to 50-170 mature individuals. However Europe represents <5% of the global range.
The overall population trend is decreasing, although some populations have stable trends (Wetlands International 2016). The tiny European population is estimated to be fluctuating (BirdLife International 2015).
Behaviour This species is both sedentary and nomadic (Urban et al. 1986, del Hoyo et al. 1996, Hockey et al. 2005), often making local movements (Taylor and van Perlo 1998) in response to rainfall, water levels and the availability of its favoured foods (Urban et al. 1986, del Hoyo et al. 1996, Hockey et al. 2005) (e.g. pondweed Potamogeton pectinatus) (Urban et al. 1986). The timing of the breeding season varies geographically (del Hoyo et al. 1996). The species is a solitary territorial breeder (Urban et al. 1986, del Hoyo et al. 1996) although it is occasionally observed in family groups (Hockey et al. 2005), with flocks of non-breeding individuals also occurring during the breeding season (Taylor and van Perlo 1998, Hockey et al. 2005). After breeding the species becomes more gregarious (Urban et al. 1986, del Hoyo et al. 1996), forming flocks which range in size from small groups of 10-12 individuals, to larger, loose-knit groups of 20-330 (Langrand 1990), occasionally also to large flocks of up to 1,000 or more (Hockey et al. 2005). Adults may undergo a flightless moult period that lasts 49-59 days at any time of the year (Urban et al. 1986, Taylor and van Perlo 1998). During this time moulting birds remain out on open water among full-winged birds, possibly to avoid predation (Urban et al. 1986, Taylor and van Perlo 1998). Habitat The species requires wetlands with submerged aquatic vegetation and still water for foraging, and waters with fringing or emergent vegetation in which to nest when breeding (del Hoyo et al. 1996). During periods of flightless moult adults also prefer more permanent open waters rich in submerged aquatic vegetation (Taylor and van Perlo 1998). Suitable habitats include open freshwater or slightly brackish (Langrand 1990, Gomez 2002) lakes, lagoons, ponds, dams, and permanent or temporary pans, flood-plains (Urban et al. 1986, del Hoyo et al. 1996, Hockey et al. 2005), sewage ponds, reed, papyrus and Typha swamps (Urban et al. 1986, del Hoyo et al. 1996, Hockey et al. 2005), and occasionally rivers and tidal lagoons (Urban et al. 1986, del Hoyo et al. 1996). Diet The species is omnivorous, its diet consisting predominantly of the shoots, fruits and seeds of submerged or floating aquatic plants (such as aquatic ferns Marsila spp., knotweed Aeschynomene fluitans, Polygonum limbatum, saw-weed Najas pectinata, pondweed Potamogeton pectinatus, ditch grass Ruppia maritima and water hyacinth Eichhornia crassipes), filamentous and macroscopic algae (Hockey et al. 2005), and grass, as well as molluscs, crustaceans, insects and occasionally carrion (Urban et al. 1986, del Hoyo et al. 1996). Breeding site The nest is a platform of reeds and other aquatic plant material (Urban et al. 1986, del Hoyo et al. 1996, Taylor and van Perlo 1998) built either on open water (Urban et al. 1986, del Hoyo et al. 1996, Taylor and van Perlo 1998) (sometimes anchored to water-lilies or on rafts of fresh, green reeds) (Urban et al. 1986, del Hoyo et al. 1996, Taylor and van Perlo 1998), or within emergent vegetation (Urban et al. 1986, del Hoyo et al. 1996, Taylor and van Perlo 1998) on a foundation of bent and trampled stems (Taylor and van Perlo 1998). No attempt at concealing the nest is made (Urban et al. 1986, del Hoyo et al. 1996), although the site chosen usually facilitates quick and easy access to open water (Hockey et al. 2005). Management information Adequate wetland management can increase the breeding success of this species (e.g. limiting the areas with grazing livestock, maintaining stable water-levels during the breeding season,providing more vegetation for nesting and reducing disturbance can all have positive effects) (Gomez 2002).
The species is susceptible to avian botulism (Blaker 1967, van Heerden 1974) so may be threatened by future outbreaks of the disease. It is also threatened by poisoning, both intentionally (pest control) and unintentionally (pesticides used on crops) (Hockey et al. 2005). The species is threatened in Spain and Morocco (the northernmost range extremes) primarily by habitat loss and degradation due to changes in hydrological regime, over-exploitation of catchments and sedimentation (which are altering the periods of wetland flooding), agricultural, industrial and domestic pollution, overgrazing (cattle herds), the burning of reeds, and the introduction of alien species (e.g. Louisiana Swamp Crayfish Procambarus clarkii and Ciprinidae fish which both reduce the availability of food and hence increase competition) (Gomez 2000).
Conservation Actions Underway
Bern Convention Appendix II. EU Birds Directive Annex I. An International Species Action Plan was published in 2000 (Gomez 2000). It is listed as Critically Endangered on the Red Lists of Spain and Portugal (Madroño et al. 2004, Cabral et al. 2005).
Conservation Actions Proposed
Key sites for this species should be restored and conserved to increase the extent of available habitat. Its ecology, habitat requirements and movements should be researched and monitoring of the evolution and state of the population undertaken. Public awareness of the need to protect the species and its habitat should be raised. Development and implementation of the Regional Recovery Plans of the species, as well as legal protection of the species and its key sites are needed. Restrict the hunting of Common Coot (Fulica atra) at sites where the Crested Coot is regularly recorded. Keep a breeding population of the species in captivity to ensure a genetic stock of individuals, in addition to increasing the productivity of the wild population by the systematic reintroduction of captive individuals into its natural habitats (Gomez 2000).
Text account compilers
Ashpole, J, Butchart, S., Ekstrom, J., Malpas, L.
BirdLife International (2020) Species factsheet: Fulica cristata. Downloaded from http://www.birdlife.org on 06/08/2020. Recommended citation for factsheets for more than one species: BirdLife International (2020) IUCN Red List for birds. Downloaded from http://www.birdlife.org on 06/08/2020.