LC
Ruff Calidris pugnax



Justification

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 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.

Population justification
The European population is estimated at 265,000-1,650,000 calling or lekking males, which equates to 531,000-3,310,000 mature individuals or 797,000-4,970,000 individuals (BirdLife International 2015). Europe forms approximately 50% of the global range so a very preliminary estimate of the global population size is 1,594,000-9,940,000 individuals. The global population was previously estimated to number 2,000,000-2,600,000 individuals (Wetlands International 2006). The upper estimate of the European population size is considerably larger than the Wetlands International (2006) global estimate. The extrapolated European population size is therefore used here and the population placed in the band 1,500,000-9,999,999 individuals.

Trend justification
The overall population trend is decreasing, although some populations have unknown trends (Wetlands International 2015). There is evidence to suggest that the European population (265,000-1,650,000 calling or lekking males, occupying c. 50% of the global breeding range) has declined by less than 25% in 15.9 years (three generations). This may reflect shifts in breeding populations, populations in Asia are not thought to be declining and wintering populations in Africa appear to be increasing.

Distribution and population

Ecology

This species is fully migratory and travels on a broad front across Europe (del Hoyo et al. 1996). It breeds from May to August (Hayman et al. 1986) with males gathering in suitable lekking areas (del Hoyo et al. 1996, Flint et al. 1984) and females nesting solitarily or in semi-colonial groups (del Hoyo et al. 1996). The species departs the breeding grounds between late-June and August, returning from the wintering grounds from March to mid-May (del Hoyo et al. 1996). The species migrates in large flocks of hundreds or thousands of individuals (del Hoyo et al. 1996) and forms huge dense groups on its wintering grounds (Hayman et al. 1986). The species inhabits tundra habitats from the coast to the Arctic treeline (Johnsgard et al. 1981, del Hoyo et al. 1996) during the breeding season, requiring adjacent foraging, lekking and nesting areas (del Hoyo et al. 1996). It shows a preference for dry mounds and slopes with low willow Salix spp. and dwarf birch Betula spp. as lekking areas (del Hoyo et al. 1996, Snow and Perrins 1998), and dry patches of tall sedge as nesting sites (Snow and Perrins 1998). Suitable foraging habitats include littoral belts, deltas (Snow and Perrins 1998), coastal saltmarshes (Johnsgard et al. 1981) and extensive lowland freshwater wetlands such as small shallow lakes with marginal vegetation (Johnsgard et al. 1981, Hayman et al. 1986, del Hoyo et al. 1996, Snow and Perrins 1998), grassy hummocky marshes (Johnsgard et al. 1981, Hayman et al. 1986, del Hoyo et al. 1996, Snow and Perrins 1998), and damp swampy grasslands (Johnsgard et al. 1981, Hayman et al. 1986, del Hoyo et al. 1996), with shallow pools or ditches (del Hoyo et al. 1996). During the non-breeding season the species occupies the muddy margins of brackish, saline and alkaline lakes, ponds, pools, rivers, marshes and food-plains (del Hoyo et al. 1996), as well as freshly mown or grazed short-sward grasslands (Hayman et al. 1986, del Hoyo et al. 1996) and wheat- or rice-fields (del Hoyo et al. 1996), usually roosting at night in the shallow waters of lake shores (del Hoyo et al. 1996). The species rarely utilises intertidal habitats (Hayman et al. 1986) but may frequent tidal mudflats and lagoons in India (del Hoyo et al. 1996). During the breeding season the species's diet consists almost entirely of adult and larval terrestrial and aquatic insects such as Coleoptera and Diptera (del Hoyo et al. 1996). On passage and during the winter the species takes insects (e.g. caddisflies, water-bugs, mayflies and grasshoppers), small crustaceans, spiders, small molluscs, annelid worms, frogs, small fish and the seeds of rice and other cereals, sedges, grasses and aquatic plants (del Hoyo et al. 1996). The nest is a shallow scrape (del Hoyo et al. 1996) concealed in marsh vegetation or meadow grass (del Hoyo et al. 1996) on damp ground (Johnsgard et al. 1981) usually more than 100 m away from the nearest lek site (Johnsgard et al. 1981). The species nests solitarily or semi-colonially, neighbouring nests occasionally only a few metres apart (del Hoyo et al. 1996). Management information Intensive grazing of grassland (> 1 cow per hectare) was found to attract a higher abundance of this species in Hungary (Baldi et al. 2005).

Threats

The species is threatened by petroleum pollution (Grishanov 2006), wetland and flood-plain drainage ( del Hoyo et al. 1996, Grishanov 2006) (for irrigation and water management) (Grishanov 2006), peat-extraction, and land abandonment and changing land management practices that lead to scrub and reed overgrowth (Grishanov 2006). The species may also suffer future population declines and range contractions as a result of global climate change (Zöckler 2002), and is susceptible to avian influenza (Melville and Shortridge 2006, Gaidet et al. 2007), avian botulism (Blaker 1967, van Heerden 1974, Hubalek et al. 2005) and avian malaria (Mendes et al. 2005), so may be threatened by future outbreaks of these diseases.

Conservation actions

Conservation Actions Underway
CMS Appendix II. EU Birds Directive Annex I and II. The following information refers to the species's European range only: An EU LIFE project in Denmark has succeeded in improving conditions for this species (Marsbøll and Aaser 2009) and another EU LIFE project in Germany aims to restore numbers of this species (Anon. 2012).

Conservation Actions Proposed
The following information refers to the species's European range only: Continue ensuring adequate protection of important breeding and wintering sites and promote favourable land management practices. Ensure that suitable legislation on petroleum drilling transportation is in place and enforced.

Acknowledgements

Text account compilers
Butchart, S., Ekstrom, J., Harding, M., Malpas, L., Symes, A., Ashpole, J


Recommended citation
BirdLife International (2017) Species factsheet: Calidris pugnax. Downloaded from http://www.birdlife.org on 17/12/2017. Recommended citation for factsheets for more than one species: BirdLife International (2017) IUCN Red List for birds. Downloaded from http://www.birdlife.org on 17/12/2017.