View source for Ruff (bird)

{{Short description|Species of bird}}
{{Distinguish|ruffe}}
{{pp-move|small=yes}}
{{Featured article}}
{{Speciesbox
| name = Ruff
| status = LC
| status_system = IUCN3.1
| status_ref = <ref name="iucn status 12 November 2021">{{cite iucn |author=BirdLife International |date=2016 |title=''Calidris pugnax'' |volume=2016 |article-number=e.T22693468A86591264 |doi=10.2305/IUCN.UK.2016-3.RLTS.T22693468A86591264.en |access-date=12 November 2021}}</ref> (Global)
| status2 = NT
| status2_system = IUCN3.1
| status2_ref = <ref name="iucn status 12 November 2021">{{cite iucn |author=BirdLife International |date=2016 |title=''Calidris pugnax'' |volume=2016 |article-number=e.T22693468A86591264 |doi=10.2305/IUCN.UK.2016-3.RLTS.T22693468A86591264.en |access-date=12 November 2021}}</ref>(European)
| image = Philomachus pugnaxRuffKampfläufer.JPG
| image_alt = Male Ruff in breeding plumage with prominent neck feathers, white underparts, and flanks blotched with black.
| image_caption = Male in breeding plumage at Darscholacke, Seewinkel, Burgenland, Austria
| image2 = Combattant varié Korba001.jpg 
| image2_caption = Female on migration at [[Korba, Tunisia|Korba]], Tunisia
| genus = Calidris
| species = pugnax
| authority = ([[Carl Linnaeus|Linnaeus]], 1758)
| synonyms = *''Philomachus pugnax'' {{small|(Linnaeus,&nbsp;1758)}}
*''Tringa pugnax'' {{small|Linnaeus,&nbsp;1758}}
| range_map = Philomachuspugnaxmap.png
| range_map_alt =Generally Ruffs migrate north and breed in the northern hemisphere from about May to August, and generally at the end of the breeding season they migrate south and spend several months the subtropics before migrating north again
| range_map_caption = Range of ''P. pugnax'' {{leftlegend|#E7E900|Breeding summer visitor|outline=gray}}{{leftlegend|#00C600|Present all year|outline=gray}}{{leftlegend|#0081DA|Non-breeding range|outline=gray}}
}}

The '''ruff''' ('''''Calidris pugnax''''') is a medium-sized [[wader|wading bird]] that breeds in [[marsh]]es and wet [[meadow]]s across northern [[Palearctic|Eurasia]]. This highly [[gregarious]] [[Scolopacidae|sandpiper]] is [[bird migration|migratory]] and sometimes forms huge flocks in its winter grounds, which include southern and western Europe, Africa, southern Asia and Australia.

The ruff is a long-necked, pot-bellied bird. This species shows marked [[Sexual dimorphism#Birds|sexual dimorphism]]; the male is much larger than the female (the reeve), and has a breeding [[plumage]] that includes brightly coloured head tufts, bare orange facial skin, extensive black on the breast, and the large collar of ornamental feathers that inspired this bird's English name. The female and the non-breeding male have grey-brown upperparts and mainly white underparts. Three differently plumaged types of male, including a rare form that mimics the female, use a variety of strategies to obtain mating opportunities at a [[lek (mating arena)|lek]], and the colourful head and neck feathers are erected as part of the elaborate main courting display. The female has one brood per year and lays four [[Bird egg|eggs]] in a well-hidden ground [[bird nest|nest]], incubating the eggs and rearing the chicks, which are mobile soon after hatching, on her own. Predators of wader chicks and eggs include mammals such as [[fox]]es, [[feral cat]]s and [[stoat]]s, and birds such as large [[gull]]s, [[crow]]s and [[skua]]s.

The ruff [[forage]]s in wet grassland and soft mud, probing or searching by sight for edible items. It primarily feeds on soil invertebrates, especially in the breeding season, but it will consume plant material, including [[rice]] and maize, on migration and in winter. Classified as "[[Least Concern|least concern]]" on the [[IUCN Red List]] criteria, the global [[bird conservation|conservation]] concerns are relatively low because of the large numbers that breed in Scandinavia and the Arctic. However, the range in much of Europe is contracting because of land drainage, increased fertiliser use, the loss of mown or grazed breeding sites, and over-hunting. This decline has seen it listed in the ''[[Agreement on the Conservation of African-Eurasian Migratory Waterbirds]]'' (AEWA).

==Taxonomy and nomenclature==
The ruff is a [[wader]] in the large family [[Scolopacidae]], the typical shorebirds. Recent research suggests that it is in a near-basal position in the genus ''[[Calidris]]'', the [[Sister group|sister taxon]] to all of the species except for the knot group ([[red knot]], [[great knot]] and [[surfbird]]).<ref name="Černý">{{cite journal | last1=Černý | first1=David | last2=Natale | first2=Rossy | title=Comprehensive taxon sampling and vetted fossils help clarify the time tree of shorebirds (Aves, Charadriiformes) | journal=Molecular Phylogenetics and Evolution | volume=177 | date=2022 | doi=10.1016/j.ympev.2022.107620 | doi-access=free | article-number=107620 | url=https://www.biorxiv.org/content/biorxiv/early/2021/07/16/2021.07.15.452585.full.pdf | access-date=2025-10-12}}</ref> It has no recognised subspecies or geographical variants.<ref name=Hayman1986a/>

This species was first described by [[Carl Linnaeus]] in his ''[[Systema Naturae]]'' in 1758 as ''Tringa pugnax''.<ref name=Linnaeus1758/> It was moved to the monotypic genus ''Philomachus'' by [[Germany|German]] [[natural history|naturalist]] [[Blasius Merrem]] in 1804.<ref name=Merrem1804/> More recent DNA research has shown it fits comfortably into the wader genus ''Calidris''.<ref name=Thomas2004/><ref name="Černý"/> The genus name comes from the [[Ancient Greek]] ''kalidris'' or ''skalidris'', a term used by [[Aristotle]] for some grey-coloured waterside birds.<ref name="Jobling"/> The [[specific epithet]] refers to the aggressive behaviour of the bird at its [[Lek (mating arena)|mating arenas]] — ''pugnax'' from the [[Latin]] term for "combative".<ref name=Simpson1979/>

The original English name for this bird, dating back to at least 1465, is the ''ree'', perhaps derived from a dialectical term meaning "frenzied";<ref name=Lockwood1984/> a later name ''reeve'', which is still used for the female, is of unknown origin, but may be derived from the [[sheriff|shire-reeve]], a feudal officer, likening the male's flamboyant plumage to the official's robes. The current name was first recorded in 1634, and is derived from the [[ruff (clothing)|ruff]], an exaggerated collar fashionable from the mid-sixteenth century to the mid-seventeenth century, since the male bird's neck ornamental feathers resemble the neck-wear.<ref name=Cocker2005/>

==Description==
[[File:Ruff (52343729225).jpg|thumb|left|alt=Juvenile, showing the peachy-buff breast colour and broadly fringed mantle and wing covert feathers |Male in juvenile plumage, St Petersburg, Russia]]
The ruff has a distinctive pot-bellied appearance, with a small head, medium-length bill, longish neck and heavy body. It has long legs that are variable in colour, being dark greenish in juveniles, pink to orange in adults with some males having reddish orange legs only during the breeding season.<ref name=Hayman1986a/> In flight, it has a deeper, slower wing stroke than other waders of a similar size, and displays a thin, indistinct white bar on the wing, and white ovals on the sides of the tail.<ref name=Mullarney1999/> The species shows [[sexual dimorphism]]. Although a small percentage of males resemble females,<ref name=Jukema2006/> the typical male is much larger than the female and has an elaborate breeding plumage. The males are {{convert|29|–|32|cm|in|abbr=on}} long with a {{convert|54|–|60|cm|in|abbr=on}} wingspan,<ref name=Mullarney1999/> and weigh from {{convert|130|–|254|g|oz|abbr=on}}, the largest species in the genus ''Calidris''.<ref name=delhoyo1996/> In the May-to-June breeding season, the male's legs, bill and warty bare facial skin are orange, and he has distinctive head tufts and a neck ruff. These ornaments vary on individual birds, being black, chestnut or white, with the colouring solid, barred or irregular.<ref name=Mullarney1999/> The grey-brown back has a scale-like pattern, often with black or chestnut feathers, and the underparts are white with extensive black on the breast.<ref name=Hayman1986a/> The extreme variability of the main breeding plumage is thought to have developed to aid individual recognition in a species that has communal breeding displays, but is usually mute.<ref name=Lank2001/>

Outside the breeding season, the male's head and neck decorations and the bare facial skin are lost and the legs and bill become duller. The upperparts are grey-brown, and the underparts are white with grey mottling on the breast and flanks.<ref name=Mullarney1999/>
The females, or "reeve", is {{convert|22|–|26|cm|in|abbr=on}} long with a {{convert|46|–|49|cm|in|abbr=on}} wingspan,<ref name=Mullarney1999/> and weighs from {{convert|70|–|170|g|oz|abbr=on}}.<ref name=delhoyo1996/> In breeding plumage, they have grey-brown upperparts with white-fringed, dark-centred feathers. The breast and flanks are variably blotched with black. In winter, the females' plumage is similar to that of the male, but the sexes are distinguishable by their size.<ref name=Hayman1986a/> The plumage of the juveniles resembles the non-breeding adult, but has upperparts with a neat, scale-like pattern with dark feather centres, and a strong buff tinge to the underparts.<ref name=Mullarney1999/>

Adult male ruffs start to [[moult]] into the main display plumage before their return to the breeding areas, and the proportion of birds with head and neck decorations gradually increases through the spring. Second-year birds lag behind full adults in developing breeding plumage. They have a lower body weight and a slower weight increase than full adults, and perhaps the demands made on their energy reserves during the migration flight are the main reason of the delayed moult.<ref name=Karlionova2008/>

Ruffs of both sexes have an additional moult stage between the winter and final summer plumages, a phenomenon also seen in the [[bar-tailed godwit]]. Before developing the full display finery with coloured ruff and tufts, the males replace part of their winter plumage with striped feathers. Females also develop a mix of winter and striped feathers before reaching their summer appearance. The final male breeding plumage results from the replacement of both winter and striped feathers, but the female retains the striped feathers and replaces only the winter feathers to reach her summer plumage. The striped prebreeding plumages may represent the original breeding appearance of this species, the male's showy courtship feathers evolving later under strong [[sexual selection]] pressures.<ref name=Jukema2000/>

Adult males and most adult females start their pre-winter moult before returning south, but complete most feather replacement on the wintering grounds. In [[Kenya]], males moult 3–4 weeks ahead of the females, finishing before December, whereas females typically complete feather replacement during December and early January. Juveniles moult from their first summer body plumage into winter plumage during late September to November, and later undergo a pre-breeding moult similar in timing and duration to that of the adults, and often producing as brightly coloured an appearance.<ref name=Pearson1981/>

Two other waders can be confused with the ruff. The juvenile [[sharp-tailed sandpiper]] is a little smaller than a juvenile female ruff and has a similar rich orange-buff breast, but the ruff is slimmer with a longer neck and legs, a rounder head, and a much plainer face.<ref name=Britton1980/> The [[buff-breasted sandpiper]] also resembles a small juvenile ruff, but even the female ruff is noticeably larger than the sandpiper, with a longer bill, more rotund body and scaly-patterned upperparts.<ref name=Vinicombe1993/>

==Distribution and habitat==
[[File:Ruff1, crop.jpg|thumb|upright|alt=A ruff in flight|Ruff in flight, showing the white sides to the rump and the narrow white wingbar; Nepal]]
The ruff is a migratory species, breeding in wetlands in colder regions of northern Eurasia, and spends the northern winter in the [[tropics]], mainly in Africa. Some Siberian breeders undertake an annual round trip of up to {{convert|30000|km|mi|abbr=on}} to the West African wintering grounds.<ref name=Vaillancourt2005/> There is a limited overlap of the summer and winter ranges in western Europe.<ref name=Hayman1986a/> The ruff breeds in extensive lowland freshwater marshes and damp grasslands.<ref name=Hayman1986a/> It avoids barren [[tundra]] and areas badly affected by severe weather, preferring hummocky marshes and deltas with shallow water. The wetter areas provide a source of food, the mounds and slopes may be used for [[Lek (mating arena)|leks]], and dry areas with [[Cyperaceae|sedge]] or low [[scrubland|scrub]] offer nesting sites.<ref name=Snow1998/> A Hungarian study showed that moderately intensive grazing of grassland, with more than one cow per hectare (2.5&nbsp;acres), was found to attract more nesting pairs.<ref name=birdlife/> When not breeding, the birds use a wider range of shallow wetlands, such as [[irrigation|irrigated fields]], lake margins, and mining [[subsidence]] and other floodlands. Dry grassland, tidal mudflats and the seashore are less frequently used.<ref name=Snow1998/> The density can reach 129 individuals per square kilometre (334 per square mile), but is usually much lower.<ref name=Blokhin1998/>

The ruff breeds in Europe and Asia from Scandinavia and Great Britain almost to the Pacific. In Europe it is found in cool temperate areas, but over its Russian range it is an Arctic species, occurring mainly north of about 65°N. The largest numbers breed in Russia (more than 1 million pairs), Sweden (61,000 pairs), Finland (39,000 pairs) and Norway (14,000 pairs). Although it also breeds from Britain east through the Low Countries to Poland, Germany and Denmark, there are fewer than 2,000 pairs in these more southerly areas.<ref name=jncc/>
[[File:Ruffs (Philomachus pugnax) W IMG 6570.jpg|thumb|left|alt=Eight winter-plumage birds standing in a pool in India.|Wintering in India]]
It is highly gregarious on migration, travelling in large flocks that can contain hundreds or thousands of individuals. Huge dense groups form on the wintering grounds;<ref name=birdlife/> one flock in [[Senegal]] contained a million birds.<ref name=Hayman1986a/> A minority winter further east to Burma, south China,<ref name=Hayman1986a/> New Guinea and scattered parts of southern Australia,<ref name=Slater1970/> or on the Atlantic and Mediterranean coasts of Europe. In Great Britain and parts of coastal western Europe, where the breeding and wintering ranges overlap, birds may be present throughout the year.<ref name=Snow1998/> Non-breeding birds may also remain year round in the tropical wintering quarters. The Ruff is an uncommon visitor to Alaska (where it has occasionally bred), Canada and the contiguous states of the US, and has wandered to Iceland, Middle America, northern South America, Madagascar and New Zealand.<ref name=Hayman1986a/><ref name=Johnson2007/> It has been recorded as breeding well south of its main range in northern [[Kazakhstan]], a major migration stopover area.<ref name=unep/><ref name=Khrokov1988/>

The male, which plays no part in nesting or chick care, leaves the breeding grounds in late June or early July, followed later in July by the female and juveniles.<ref name=Baccetti1998a/> Males typically make shorter flights and winter further north than females; for example, virtually all wintering ruffs in Britain are males,<ref name=Berthold2001/> whereas in Kenya most are females.<ref name=Pearson1981/> Many migratory species use this differential wintering strategy, since it reduces feeding competition between the sexes and enables territorial males to reach the breeding grounds as early as possible, improving their chances of successful mating. Male ruffs may also be able to tolerate colder winter conditions because they are larger than females.<ref name=Berthold2001/>

Birds returning north in spring across the central Mediterranean appear to follow a well-defined route. Large concentrations of ruffs form every year at particular [[layover|stopover]] sites to feed, and individuals marked with [[bird ringing|rings]] or dye reappear in subsequent years. The refuelling sites are closer together than the theoretical maximum travel distance calculated from the mean body weight, and provide evidence of a migration strategy using favoured intermediate sites.<ref name=Baccetti1998a/> The ruff stores fat as a fuel, but unlike mammals, uses [[lipid]]s as the main energy source for exercise (including migration) and, when necessary, keeps warm by shivering; however, little research has been conducted on the mechanisms by which they [[Oxidation#Redox reactions in biology|oxidise]] lipids.<ref name=Vaillancourt2005/>

==Behaviour==

===Mating===
[[File:Philomachus pugnax naumann.jpg|thumb|left|alt=A white-collared satellite male and a brown-collared territorial male are displaying to each other. Two more males are in the background, and a female is in the foreground.| Illustration of a lek by [[Johann Friedrich Naumann]] (1780–1857)]]
[[File:Nederlandsche vogelen (KB) - Philomachus pugnax (028b).jpg|thumb|Ruff in ''[[Nederlandsche Vogelen]]'',<br />Vol. 1 (1770)]]
[[File:Vaenius - Alexander Farnese.jpg|thumb|upright|alt= A sixteenth-century painting of a man wearing a ruff, the decorative collar from which the English name of the bird derives. He is wearing a black dress with a particularly large and elaborate white lacy ruff.|[[Otto van Veen]]'s sixteenth-century painting of [[Alexander Farnese, Duke of Parma]] wearing a [[ruff (clothing)|ruff]], the decorative collar from which the English name of the bird is derived.]]
Males display during the breeding season at a [[lek (mating arena)|lek]] in a traditional open grassy arena. The ruff is one of the few lekking species in which the display is primarily directed at other males rather than to the females, and it is among the small percentage of birds in which the males have well-marked and [[Mendelian inheritance|inherited]] variations in plumage and mating behaviour.<ref name=Roulin2004/><ref name=Payne1984/> There are three male forms: the typical territorial males, satellite males which have a white neck ruff, and a very rare variant with female-like plumage. The behaviour and appearance for an individual male remain constant through its adult life, and are determined by its [[gene]]s (see [[#Biology of variation among males|§Biology of variation among males]]).

The territorial males, about 84% of the total, have strongly coloured black or chestnut ruffs and stake out and occupy small mating territories in the lek. They actively court females and display a high degree of aggression towards other resident males;<ref name=Snow1998/> 5–20 territorial males each hold an area of the lek about {{convert|1|m|yd|abbr=on}} across, usually with bare soil in the centre. They perform an elaborate display that includes wing fluttering, jumping, standing upright, crouching with ruff erect, or lunging at rivals.<ref name=Mullarney1999/> They are typically silent even when displaying, although a soft ''gue-gue-gue'' may occasionally be given.<ref name=Snow1998/>

[[Territory (animal)|Territorial]] males are very site-faithful; 90% return to the same lekking sites in subsequent seasons, the most dominant males being the most likely to reappear. Site-faithful males can acquire accurate information about the competitive abilities of other males, leading to well-developed dominance relationships. Such stable relationships reduce conflict and the risk of injury, and the consequent lower levels of male aggression are less likely to scare off females. Lower-ranked territorial males also benefit from site fidelity since they can remain on the leks while waiting for the top males eventually to drop out.<ref name=Widemo1997/>

Satellite males, about 16% of the total number, have white or mottled ruffs and do not occupy territories; they enter leks and attempt to mate with the females visiting the territories occupied by the resident males.<ref name=Lank1995/> Resident males tolerate the satellite birds because, although they are competitors for mating with the females, the presence of both types of male on a territory attracts additional females.<ref name=Hill1991/><ref name=Hugie1997/> Females also prefer larger leks,<ref name=Lank1992/> and leks surrounded by taller plants, which give better nesting habitat.<ref name=Hoglund1998/>

Although satellite males are on average slightly smaller and lighter than residents, the nutrition of the chicks does not, as previously thought, influence mating strategy; rather, the inherited mating strategy influences body size. Resident-type chicks will, if provided with the same amount of food, grow heavier than satellite-type chicks. Satellite males do not have to expend energy to defend a territory, and can spend more time foraging, so they do not need to be as bulky as the residents; indeed, since they fly more, there would be a physiological cost to additional weight.<ref name=Lank1995/>

A third type of male was first described in 2006; this is a permanent female mimic, or "faeder" ([[Old English]] "father"), the first such reported for a bird. About 1% of males are small, intermediate in size between males and females, and do not grow the elaborate breeding plumage of the territorial and satellite males, although they have much larger internal [[testicle|testes]] than the ruffed males.<ref name=Jukema2006/> Although the males of most lekking bird species have relatively small testes for their size, male ruffs have the most disproportionately large testes of any bird.<ref name=birkhead2011323>Birkhead (2011) p. 323.</ref>

These cryptic males obtains access to mating territories together with the females, and "steals" matings when the females crouch to solicit copulation.<ref name=Jukema2006/> The faeder moults into the prebreeding male plumage with striped feathers, but does not go on to develop the ornamental feathers of the more common males. As described above, this stage is thought to show the original male breeding plumage, before other male types evolved. A faeder can be distinguished in the hand by its wing length, which is intermediate between those of displaying males and females.<ref name=Karlionova2007/> Despite their feminine appearance, the faeders migrate with the larger lekking males and spend the winter with them.<ref name=Verkuil2008/>
The faeders are sometimes mounted by independent or satellite males, but are as often "on top" in [[homosexual behavior in animals|homosexual mountings]] as the ruffed males, suggesting that their true identity is known by the other males. Females never mount males.<ref name=Jukema2006/> Females often seem to prefer mating with faeders to copulation with the more common males, and those males also copulate with faeders (and ''vice versa'') relatively more often than with females. The homosexual copulations may attract females to the lek, like the presence of satellite males.<ref name=Hooijmeijer2009/>

Not all mating takes place at the lek, since only a minority of the males attend an active lek. As alternative strategies, males can also directly pursue females ("following") or wait for them as they approached good feeding sites ("intercepting"). Males switched between the three tactics, being more likely to attend a lek when the copulation rate the previous day was high or when fewer females were available after nesting had started. Lekking rates were low in cold weather early in the season when off-lek males spent most of their time feeding.<ref name=Lank1987/>

The level of [[Polyandry in animals|polyandry]] in the ruff is the highest known for any avian lekking species and for any shorebird. More than half of female ruffs mate with, and have clutches fertilised by, more than one male, and individual females mate with males of both main behavioural morphs more often than expected by chance. In lekking species, females can choose mates without risking the loss of support from males in nesting and rearing chicks, since the males take no part in raising the brood anyway. In the absence of this cost, if polyandry is advantageous, it would be expected to occur at a higher rate in lekking than among pair-bonded species.<ref name=Lank2002/>
===Genetics of variation among males===
[[File:Philomachus_pugnax_107.jpg|thumb|upright|Skeleton of a ruff]]
As indicated above, the ruff has three male forms, which differ in mating behaviour and in appearance: the typical territorial males which have a dark neck ruff, satellite males which have a white neck ruff, and the very rare cryptic males known as "faeders" which have female-like plumage.  The behaviour and appearance of each individual male remain constant through its adult life, and are determined by a simple genetic [[polymorphism (biology)|polymorphism]].<ref name=Lank1995/> Territorial behaviour and appearance is [[recessive]] to satellite behaviour and appearance,<ref name=Lank2002/>  while preliminary research results suggest that the faeder characteristics are genetically controlled by a single dominant gene.<ref name=lankproject/>  It was originally thought that the difference between territorial and satellite males was due to a sex-linked genetic factor, but in fact the genetic [[locus (genetics)|locus]] relevant for the mating strategy is located on an [[autosome]], or non-sex [[chromosome]]. That means that both sexes can carry the two different forms of the gene, not just males. The female does not normally show evidence of her genetic type, but when females are given [[testosterone]] implants, they display the male behaviour corresponding to their [[genotype]].<ref name=Lank1999/> This testosterone-linked behaviour is unusual in birds, where external sexual characteristics are normally determined by the presence or absence of [[oestrogen]].<ref name=birkhead>Birkhead (2011) pp. 282&ndash;286.</ref>

In 2016, two studies further pinpointed the responsible region to chromosome 11 and a 4.5-[[Base pair|Mb]] covering chromosomal rearrangement.<ref>{{Cite journal|last1=Lamichhaney|first1=Sangeet|last2=Fan|first2=Guangyi|last3=Widemo|first3=Fredrik|last4=Gunnarsson|first4=Ulrika|last5=Thalmann|first5=Doreen Schwochow|last6=Hoeppner|first6=Marc P.|last7=Kerje|first7=Susanne|last8=Gustafson|first8=Ulla|last9=Shi|first9=Chengcheng|date=2016-01-01|title=Structural genomic changes underlie alternative reproductive strategies in the ruff (Philomachus pugnax)|journal=Nature Genetics|language=en|volume=48|issue=1|pages=84–88|doi=10.1038/ng.3430|issn=1061-4036|pmid=26569123|doi-access=free}}</ref><ref name="Küpper 79–83">{{Cite journal|last1=Küpper|first1=Clemens|last2=Stocks|first2=Michael|last3=Risse|first3=Judith E.|last4=dos Remedios|first4=Natalie|last5=Farrell|first5=Lindsay L.|last6=McRae|first6=Susan B.|last7=Morgan|first7=Tawna C.|last8=Karlionova|first8=Natalia|last9=Pinchuk|first9=Pavel|date=2016-01-01|title=A supergene determines highly divergent male reproductive morphs in the ruff|journal=Nature Genetics|language=en|volume=48|issue=1|pages=79–83|doi=10.1038/ng.3443|issn=1061-4036|pmid=26569125|pmc=5218575}}</ref> The scientists were able to show that the first genetic change happened 3.8 million years ago on the resident [[chromosome]], when a part of it broke off and was reintroduced in the wrong direction. This [[Chromosomal inversion|inversion]] created the faeder [[allele]]. About 500,000 years ago another rare [[Homologous recombination|recombination]] event of faeder and resident [[allele]] in the very same inverted region led to the satellite [[allele]]. The 4.5 [[Base pair|Mb]] [[Chromosomal inversion|inversion]] covers 90 genes, one of them is the [[centromere]] coding gene N- [[CENPN]]-, which is located exactly at one of the [[Chromosomal inversion|inversion]] breakpoints. The inactivation of the gene has severe deleterious effects and pedigree data of a captive ruff colony suggests that the inversion is [[Zygosity|homozygous]] [[Lethality|lethal]]. Over the course of the past 3.8 million years, further [[mutation]]s have accumulated within the [[Chromosomal inversion|inversion]] i.e. three [[Deletion (genetics)|deletions]] ranging from 3.3 to 17.6 [[Base pair|kb]]. Two of these [[Deletion (genetics)|deletions]] remove evolutionary highly conserved elements close to two genes- [[HSD17B2]] and [[SDR42E1]]-both holding important roles in [[metabolism]] of [[steroid hormone]]s. Hormone measurements around mating time showed that whereas residents have a sharp increase of [[testosterone]], faeders and satellites only experience higher [[androstenedione]] levels, a substance which is considered an [[Reaction intermediate|intermediate]] in [[testosterone]] biosynthesis. The authors conclude that one or more of the deletions act as a ''[[Cis-regulatory element|cis]]''[[Cis-regulatory element|-acting]] regulatory [[mutation]] which is altering the [[Gene expression|expression]] of one or both genes and eventually contributes to the different male [[phenotype]]s and behaviour.<ref name="Küpper 79–83"/>
{{Clear}}
===Nesting and survival===
[[File:Philomachus pugnax MWNH 0164.JPG|left|thumb|Eggs, Collection [[Museum Wiesbaden]]]]
[[File:Corvus corone Rabenkrähe 1.jpg|thumb|alt=A carrion crow picking a small food item from short grass. This species will raid the nests of wetland waders for eggs and chicks. | The [[carrion crow]] will raid the nests of wetland waders for eggs and young.]]
The nest is a shallow ground scrape lined with grass leaves and stems, and concealed in marsh plants or tall grass up to {{convert|400|m|yd|abbr=on}} from the lek. Nesting is solitary, although several females may lay in the general vicinity of a lek.<ref name=Hayman1986a/><ref name=Snow1998/> The eggs are slightly glossy, green or olive, and marked with dark blotches; they are laid from mid-March to early June depending on latitude.<ref name=Snow1998/>

The typical clutch is four eggs, each egg measuring {{convert|44|x|31|mm|in|abbr=on}} in size and weighing {{convert|21.0|g|oz|abbr=on}} of which 5% is shell. Incubation is by the female alone, and the time to hatching is 20–23 days, with a further 25–28 days to fledging.<ref name=bto/> The [[precocial]] chicks have buff and chestnut down, streaked and barred with black, and frosted with white;<ref name=Coward1930/> they feed themselves on a variety of small invertebrates, but are brooded by the female.<ref name=eaza/> One brood is raised each year.<ref name=bto/>

Ruffs often show a pronounced inequality in the numbers of each sex. A study of juveniles in Finland found that only 34% were males and 1% were faeders.<ref name=jaatinen >{{cite journal | last1 = Jaatinen | first1 = Kim | last2 = Lehikoinen | first2 = Aleksi | last3 = Lank | first3 = David B |year =2010| title  = Female-biased sex ratios and the proportion of cryptic male morphs of migrant juvenile Ruffs (''Philomachus pugnax'') in Finland | journal = Ornis Fennica | volume = 87| issue = 4 | pages = 125–134| doi = 10.51812/of.133751 | language =en, fi | url = https://www.sfu.ca/biology/wildberg/papers/JaatinenetalOrnFenn10.pdf }}</ref> It appears that females produce a larger proportion of males at the egg stage when they are in poor physical condition. When females are in better condition, any bias in the sex ratio is smaller or absent.<ref name= thuman>{{cite journal | last1 = Thuman | first1 = Katherine A | last2 = Widemo  | first2 = Fredrik | last3 = Griffith  | first3 = Simon C  |year = 2003| title  = Condition-dependent sex allocation in a lek-breeding wader, the ruff (''Philomachus pugnax'') | journal = Molecular Ecology | volume =12 | issue = 1| pages =  213–218 | doi =10.1046/j.1365-294X.2003.01717.x | pmid = 12492889 | bibcode = 2003MolEc..12..213T | s2cid = 56998 }}</ref>

Predators of waders breeding in wet grasslands include birds such as large gulls, [[common raven]], [[Carrion crow|carrion]] and [[hooded crow]]s, and [[Great skua|great]] and [[Arctic skua]]s; foxes occasionally take waders, and the impact of [[feral cats]] and stoats is unknown.<ref name=defra/><ref name=Bolton2007/><ref name=vanderWal2008/> Overgrazing can increase predation by making nests easier to find.<ref name=vanderWal2008/> In captivity, the main causes of chick mortality were stress-related sudden death and [[torticollis|twisted neck syndrome]].<ref name=eaza/> Adults seem to show little evidence of [[parasitism|external parasites]],<ref name=Threlfall1986/> but may have significant levels of disease on their tropical wintering grounds,<ref name=Mendes2005/> including [[avian malaria]] in their inland freshwater habitats,<ref name=Mendes2005/> and so they might be expected to invest strongly in their [[immune system]]s;<ref name=Piersma1997/> however, a 2006 study that analysed the blood of migrating ruffs intercepted in [[Friesland]] showed that this bird actually has unexplained low levels of immune responses on at least one measure of resistance.<ref name=Mendes2006/> The ruff can breed from its second year, and the [[life expectancy|average lifespan]] for birds that have passed the chick stage is about 4.4 years,<ref name=Lozano2004/> although a Finnish bird lived to a record 13 years and 11 months.{{cn|date=October 2025}}

===Feeding===
[[File:Tamil Nadu countryside.jpg|thumb|left|alt=A flooded rice field in [[Tamil Nadu]]. Rice paddies are a favoured winter feeding ground for ruff | Rice paddies are a favoured winter feeding ground]]
The ruff normally feeds using a steady walk and pecking action, selecting food items by sight, but it will also wade deeply and submerge its head. On saline lakes in East Africa it often swims like a [[phalarope]], picking items off the surface.<ref name=Hayman1986a/> It will feed at night as well as during the day.<ref name=delhoyo1996/> It is thought that Ruff use both visual and auditory cues to find prey.<ref>{{cite journal| author1=Onrust, J.| author2=Loonstra, A. H. J.| author3=Schmaltz, L. E.| author4=Verkuil, Y. I.| author5=Hooijmeijer, J. C. E. W.| author6=Piersma, T.| year=2017| title=Detection of earthworm prey by Ruff Philomachus pugnax| journal=Ibis| volume=159| pages=647–656| doi=10.1111/ibi.12467| issue=3| url=https://pure.rug.nl/ws/files/40946054/Onrust_J._et_al._2017_Ibis_earthworm_detection_by_ruff_.pdf| access-date=2019-02-05| archive-date=2023-03-11| archive-url=https://web.archive.org/web/20230311040655/https://pure.rug.nl/ws/files/40946054/Onrust_J._et_al._2017_Ibis_earthworm_detection_by_ruff_.pdf}}</ref> When feeding, the ruff frequently raises its back feathers, producing a loose pointed peak on the back; this habit is shared only by the black-tailed godwit.<ref name=Mullarney1999/>
During the breeding season, the ruff's diet consists almost exclusively of the adults and larva of terrestrial and aquatic insects such as beetles and flies. On migration and during the winter, the ruff eats insects (including [[Trichoptera|caddis flies]], water-beetles, [[mayfly|mayflies]] and grasshoppers), crustaceans, spiders, molluscs, worms, frogs, small fish, and also the seeds of rice and other cereals, sedges, grasses and aquatic plants.<ref name=birdlife/> Migrating birds in Italy varied their diet according to what was available at each stopover site. Green aquatic plant material, spilt rice and maize, flies and beetles were found, along with varying amounts of grit.<ref name=Bacetti1998b/> On the main wintering grounds in West Africa, rice is a favoured food during the later part of the season as the ricefields dry out.<ref name=Trolliet2001/>

Just before migration, the ruff increases its body weight at a rate of about 1% a day, much slower than the bar-tailed godwits breeding in Alaska, which fatten at four times that rate. This is thought to be because the godwit cannot use refuelling areas to feed on its trans-Pacific flight, whereas the ruff is able to make regular stops and take in food during overland migration. For the same reason, the ruff does not physiologically shrink its digestive organs to reduce bodyweight before migrating, unlike the godwit.<ref name=Piersma1998/>

==Relationship with humans==
[[File:RuffNetting.jpg|thumb|alt=An 1897 black-and-white drawing of a group of ruffs moving towards an area baited with food. Some are flying towards the food. A net lies on the ground beside the feeding area. |1897 illustration of ruffs being trapped for food with a net]]
Ruffs were formerly trapped for food in England in large numbers; on one occasion, 2,400 were served at [[George Neville (archbishop)|Archbishop Neville's]] enthronement banquet in 1465. The birds were netted while lekking, sometimes being fattened with bread, milk and seed in holding pens before preparation for the table.<ref name=Cocker2005/><ref name=Pennant1776/>
<blockquote>
...if expedition is required, sugar is added, which will make them in a fortnight's time a lump of fat: they then sell for two Shillings or half-a-crown a piece… The method of killing them is by cutting off their head with a pair of scissars{{sic}}, the quantity of blood that issues is very great, considering the size of the bird. They are dressed like the Woodcock, with their intestines; and, when killed at the critical time, say the Epicures, are reckoned the most delicious of all morsels.<ref name=Pennant1776/>
</blockquote>

The heavy toll on breeding birds, together with loss of habitat through drainage and collection by nineteenth-century trophy hunters and egg collectors, meant that the species became almost extinct in England by the 1880s, although recolonisation in small numbers has occurred since 1963.<ref name=Cocker2005/><ref name=bto/><ref name=Coward1930/> The draining of wetlands from the 1800s onwards in southern Sweden has resulted in the ruff's disappearance from many areas there, although it remains common in the north of the country.<ref name=Dahlfors2009/> The use of [[insecticide]]s and draining of wetlands has led to a decrease in the number of ruff in Denmark since the early 1900s.<ref name=naturstyrelsen/> There are still areas where the ruff and other wetland birds are hunted legally or otherwise for food.<ref name=Lane1993/><ref name=Hayman1986b/><ref name=Balmaki/> A large-scale example is the capture of more than one million waterbirds (including ruffs) in a single year from [[Lake Chilwa]] in [[Malawi]].<ref name=Kanstrup/>

Although this bird eats rice on the wintering grounds, where it can make up nearly 40% of its diet, it takes mainly waste and residues from cropping and threshing, not harvestable grain. It has sometimes been viewed as a pest, but the deeper water and presence of invertebrate prey in the economically important early winter period means that the wader has little effect on crop yield.<ref name=Trolliet1991/>

==Conservation status==
[[File:Ruff (Philomachus pugnax) near Hodal W IMG 6534.jpg|thumb|left|alt=A single winter plumage male bird facing right on short grass in India. The upperparts are brown-grey with prominent white feather edges, and the underparts are white. |Male in non-breeding plumage in India]]
The ruff has a large range, estimated at 1–10&nbsp;million&nbsp;square kilometres (0.38–3.8&nbsp;million square miles) and a population of at least 2,000,000 birds. The European population of 200,000–510,000 pairs, occupying more than half of the total breeding range, seems to have declined by up to 30% over ten years, but this may reflect geographical changes in breeding populations. The Ruff was last assessed in 2016 on a global scale, and is listed as a [[least concern]] species.<ref name="iucn status 12 November 2021" /> In 2021, the IUCN assessed the European population of the ruff as [[near-threatened]],<ref>{{cite iucn |author=BirdLife International |year=2021 |title=''Calidris pugnax'' (Europe assessment) |article-number=e.T22693468A166259298 |doi=10.2305/IUCN.UK.2021-3.RLTS.T22693468A166259298.en}}</ref> which could later reflect an uplisting of the species.

The most important breeding populations in Europe, in Russia and Sweden, are stable, and the breeding range in Norway has expanded to the south, but populations have more than halved in Finland, Estonia, Poland, Latvia and The Netherlands. Although the small populations in these countries are of limited overall significance, the decline is a continuation of trend towards range contraction that has occurred over the last two centuries. The drop in numbers in Europe has been attributed to drainage, increased fertiliser use, the loss of formerly mown or grazed breeding sites and over-hunting.<ref name=jncc/>

Fossils from the [[Pleistocene]] suggest that this species bred further south in Europe in the cool periods between glaciations than it does now.<ref name=Bochenski2002/> Its sensitivity to changing climate as well as to water table levels and the speed of vegetation growth has led to suggestions that its range is affected by global warming, and the ruff might act as an indicator species for monitoring climate change.<ref name=Zockler2002/> Potential threats to this species may also include outbreaks of diseases to which it is susceptible such as [[avian influenza|influenza]], [[botulism]] and [[avian malaria]].<ref name=birdlife/>

The ruff is one of the species to which the ''[[Agreement on the Conservation of African-Eurasian Migratory Waterbirds]]'' (AEWA) applies, where it is allocated to category 2c; that is, the populations in need of special attention as they are showing "significant long-term decline" in much of its range.<ref name=AEWA/> This commits signatories to regulate the taking of listed species or their eggs, to establish protected areas to conserve habitats for the listed species, to regulate hunting and to monitor the populations of the birds concerned.<ref name=AEWA2/>

{{Anchor|Biology of variation among males}}

==Notes==
{{Reflist|35em|refs=
<ref name=AEWA>{{cite web |title=Annex 2: Waterbird species to which the Agreement applies |work=Agreement on the conservation of African-Eurasian migratory Waterbirds (AEWA) |url=http://www.unep-aewa.org/sites/default/files/basic_page_documents/aewa_agreement_text_2016_2018_FINAL.pdf |archive-url=https://web.archive.org/web/20160404114119/http://www.unep-aewa.org/sites/default/files/basic_page_documents/aewa_agreement_text_2016_2018_FINAL.pdf |archive-date=4 April 2016 |publisher=AEWA |access-date=22 April 2008 }}</ref>

<ref name=AEWA2>{{cite web |title=Annex 3: Waterbird species to which the Agreement applies |work=Agreement on the conservation of African-Eurasian migratory Waterbirds (AEWA) |url=http://www.unep-aewa.org/sites/default/files/basic_page_documents/aewa_agreement_text_2016_2018_FINAL.pdf |archive-url=https://web.archive.org/web/20160404114119/http://www.unep-aewa.org/sites/default/files/basic_page_documents/aewa_agreement_text_2016_2018_FINAL.pdf |archive-date=4 April 2016 |publisher=AEWA |access-date=22 April 2008 }}</ref>

<ref name=Baccetti1998a>{{cite journal |last1=Baccetti |first1=N. |last2=Gambogi |first2=R. |last3=Magnani |first3=A. |last4=Piacentini |first4=D. |last5=Serra |first5=L. |year=1998 |title=Stop-over strategy of Ruff ''Philomachus pugnax'' during the spring migration |journal=International Wader Studies |volume=10 |pages=65–369 |url=http://sora.unm.edu/sites/default/files/journals/iws/n010/p00365-p00369.pdf }}</ref>

<ref name=Bacetti1998b>{{cite journal |last1=Baccetti |first1=N. |last2=Chelazzi |first2=L. |last3=Colombini |first3=I. |last4=Serra |first4=L. |year=1998 |title=Preliminary data on the diet of migrating Ruffs ''Philomachus pugnax'' in northern Italy |journal=International Wader Studies |volume=10 |pages=361–364 |url=http://sora.unm.edu/sites/default/files/journals/iws/n010/p00361-p00364.pdf}}</ref>

<ref name=Balmaki>{{cite web |last1=Balmaki |first1=Behnam |last2=Barati |first2=Ahmad |url=http://www.jncc.gov.uk/PDF/pub07_waterbirds_part6.3.8.pdf |title=Harvesting status of migratory waterfowl in northern Iran: a case study from Gilan Province}} in {{harvnb|Boere|Galbraith|Stroud|2006|pp=868–869}}</ref>

<ref name=Berthold2001>{{harvnb|Berthold|Bauer|Westhead|2001|pp=51–52}}</ref>

<ref name=birdlife>{{cite web |title=''Calidris pugnax'' |work=Species factsheet |url=https://datazone.birdlife.org/species/factsheet/ruff-calidris-pugnax |publisher=BirdLife International |access-date=12 October 2025}}</ref>

<ref name=Blokhin1998>{{cite journal |last=Blokhin |first=Yury Yu. |year=1998 |title=Spatial and temporal dynamics of wader numbers in the delta complexes of the northern subarctic |journal=International Wader Studies |volume=10 |pages=214–220 |url=http://sora.unm.edu/sites/default/files/journals/iws/n010/p00214-p00220.pdf }}</ref>

<ref name=Bochenski2002>{{cite journal |last=Bocheński |first=Zygmunt |date=November 2002 |title=Bird remains from Obłazowa – zoogeographical and evolutionary remarks |journal=Acta Zoologica Cracoviensia |volume=45 |pages=239–252|url=http://www.isez.pan.krakow.pl/journals/azc_v/pdf/45/18.pdf}}</ref>

<ref name=Bolton2007>{{cite journal |last1=Bolton |first1=Mark |last2=Tyler |first2=Glen |last3=Smith |first3=Ken |last4=Bamford |first4=Roy |year=2007 |title=The impact of predator control on lapwing ''Vanellus vanellus'' breeding success on wet grassland nature reserves |journal=Journal of Applied Ecology |volume=44 |pages=534–544 |doi=10.1111/j.1365-2664.2007.01288.x |issue=3 |doi-access=free |bibcode=2007JApEc..44..534B }}</ref>

<ref name=Britton1980>{{cite journal |last=Britton |first=David |date=August 1980 |title=Identification of Sharp-tailed Sandpipers |journal=[[British Birds (magazine)|British Birds]] |volume=73 |issue=8 |pages=333–345 |url=https://www.britishbirds.co.uk/wp-content/uploads/article_files/V73/V73_N08/V73_N08_P333_345_A085.pdf}}</ref>

<ref name=bto>{{cite web |last=Robinson |first=R.A. |year=2009 |title=Ruff ''Philomachus pugnax'' [Linnaeus, 1758] |work=BirdFacts: profiles of birds occurring in Britain & Ireland (BTO Research Report 407) |publisher=[[British Trust for Ornithology]] |location=Thetford |url=http://blx1.bto.org/birdfacts/results/bob5170.htm |access-date=16 April 2009}}</ref>

<ref name=Cocker2005>{{harvnb|Cocker|Mabey|2005|pp=211–212}}</ref>

<ref name=Coward1930>{{harvnb|Coward|1930|pp=150–154}}</ref>

<ref name=Dahlfors2009>{{cite web |last=Dahlfors |first=Steve |url=http://www.sofnet.org/1.0.1.0/1306/download_5940.php |title=Brushane Philomachus pugnax |year=2009 |publisher=SOF – Sveriges Ornitologiska Förening |language=sv |access-date=20 April 2012}}</ref>

<ref name=defra>{{cite web |title=Management of wet grassland habitat to reduce the impact of predation on breeding waders: Phase 2 |work=Science and research projects |url=http://randd.defra.gov.uk/Default.aspx?Menu=Menu&Module=More&Location=None&Completed=2&ProjectID=14810 |publisher=[[Department for Environment, Food and Rural Affairs]] (DEFRA) |access-date=23 April 2009 }}</ref>

<ref name=delhoyo1996>{{harvnb|del Hoyo|Elliot|Sargatal|1996|pp=530–531}}</ref>

<ref name=eaza>{{cite web |last=Achim |first=Johann |title=EAZA Husbandry guidelines for the Ruff (''Philomachus pugnax'') |url=http://www.eaza.net/members/DownlTAGs/HG_Ruff.PDF |publisher=[[European Association of Zoos and Aquaria]] (EAZA) |access-date=23 April 2009 |archive-url=https://web.archive.org/web/20040510100904/http://www.eaza.net/members/DownlTAGs/HG_Ruff.PDF |archive-date=10 May 2004 }}</ref>

<ref name=Hayman1986a>{{harvnb|Hayman|Marchant|Prater|1986|pp=386–387}}</ref>

<ref name=Hayman1986b>{{harvnb|Hayman|Marchant|Prater|1986|p=29}}</ref>

<ref name=Hill1991>{{cite journal |last1=Hill |first1=Wendy L. |date=December 1991 | title=Correlates of male mating success in the ruff ''Philomachus pugnax'', a lekking shorebird |journal=Behavioral Ecology and Sociobiology |volume=29 |issue=5 |pages=367–372 |doi=10.1007/BF00165962|bibcode=1991BEcoS..29..367H |s2cid=10320147 }}</ref>

<ref name=Hoglund1998>{{cite journal |last1=Hoglund |first1=Jacob |last2=Widemo |first2=Fredrik |last3=Sutherland |first3=William J. |last4=Nordenfors |first4=Helena |date=June 1998 |title=Ruffs, ''Philomachus pugnax'', and distribution models: can leks be regarded as patches? |journal=Oikos |volume=82 |issue=2 |pages=370–376 |jstor=3546978 |doi=10.2307/3546978 |bibcode=1998Oikos..82..370H }}</ref>

<ref name=Hooijmeijer2009>{{cite journal |editor-last=Hooijmeijer |editor-first=Jos |year=2009 |url=http://www.rug.nl/research/animal-ecology/publications/_pdf/ruff-newsletter-2009.pdf |journal=Newsletter Ruff Research 2009 |pages=13–14 |title=Faeders are supermen |archive-url=https://web.archive.org/web/20160412000722/http://www.rug.nl/research/animal-ecology/publications/_pdf/ruff-newsletter-2009.pdf |archive-date=2016-04-12 }}</ref>

<ref name=Hugie1997>{{cite journal |last1=Hugie |first1=Don M. |last2=Lank |first2=David B. |year=1997 |title=The resident's dilemma: a female choice model for the evolution of alternative mating strategies in lekking male ruffs (''Philomachus pugnax'') |journal=Behavioral Ecology |volume=8 |issue=2 |pages=218–225 |url=https://www.sfu.ca/biology/wildberg/Hugie&Lank1997BehavEcol.pdf |doi=10.1093/beheco/8.2.218}}</ref>

<ref name=jncc>{{cite web |title=Ruff ''Philomachus pugnax'' |work=United Kingdom [[Special Protection Area]]s |url=http://www.jncc.gov.uk/pdf/UKSPA/UKSPA-A6-68A.pdf |publisher=[[Joint Nature Conservation Committee]] |access-date=16 April 2009}} Estimates for the Russian population vary widely, and I have used the minimum figure given in {{harvnb|Snow|Perrins|1998|pp=628–632}}</ref>

<ref name="Jobling">{{cite book | last= Jobling | first= James A | year= 2010| title= The Helm Dictionary of Scientific Bird Names | url= https://archive.org/details/Helm_Dictionary_of_Scientific_Bird_Names_by_James_A._Jobling | publisher=Christopher Helm | location = London | isbn = 978-1-4081-2501-4 | page=[https://archive.org/details/Helm_Dictionary_of_Scientific_Bird_Names_by_James_A._Jobling/page/n84 84]}}</ref>

<ref name=Johnson2007>{{cite journal |last1=Johnson |first1=James A. |last2=Lanctot |first2=Richard B. |last3=Andres |first3=Brad A. |last4=Bart |first4=Jonathan R. |last5=Brown |first5=Stephen C. |last6=Kendall |first6=Steven J. |last7=Payer |first7=David C. |date=September 2007 |title=Distribution of breeding shorebirds on the Arctic coastal plain of Alaska |journal=Arctic |volume=60 |issue=3 |pages=277–293 |url=http://pubs.aina.ucalgary.ca/arctic/Arctic60-3-277.pdf| doi = 10.14430/arctic220|bibcode=2007Arcti..60..277J }}</ref>

<ref name=Jukema2000>{{cite journal |last1=Jukema |first1=Joop |last2=Piersma |first2=Theunis |year=2000 |title=Contour feather moult of Ruffs ''Philomachus pugnax'' during northward migration, with notes on homology of nuptial plumages in scolopacid waders |journal=Ibis |volume=142 |issue=2 |pages=289–296 |doi=10.1111/j.1474-919X.2000.tb04868.x|s2cid=55914458 |url=https://pure.rug.nl/ws/files/6659948/2000IbisJukema.pdf }}</ref>

<ref name=Jukema2006>{{cite journal |last1=Jukema |first1=Joop |last2=Piersma |first2=Theunis |year=2006 |title=Permanent female mimics in a lekking shorebird |journal=Biology Letters |volume=2 |issue=2 |pages=161–164 |url=https://www.rug.nl/research/portal/files/6700647/2006BiolLettJukema.pdf |doi=10.1098/rsbl.2005.0416 |pmid=17148353 |pmc=1618908}}</ref>

<ref name=Kanstrup>{{cite web |last=Kanstrup |first=Niels |url=http://www.jncc.gov.uk/PDF/pub07_waterbirds_part2.2.7.pdf |title=Sustainable harvest of waterbirds: a global review}} in  {{harvnb|Boere|Galbraith|Stroud|2006|pp=868–869}}</ref>

<ref name=Karlionova2007>{{cite journal |last1=Karlionova |first1=Natalia |last2=Pinchuk |first2=Pavel |last3=Meissner |first3=Włodzimierz |last4=Verkuil |first4=Yvonne |year=2007 |title=Biometrics of Ruffs ''Philomachus pugnax'' migrating in spring through southern Belarus with special emphasis on the occurrence of 'faeders' |journal=Ringing & Migration |volume=23 |pages=134–140 |doi=10.1080/03078698.2007.9674359 |issue=3|doi-access=free }}</ref>

<ref name=Karlionova2008>{{cite journal |last1=Karlionova |first1=Natalia |last2=Meissner |first2=Włodzimierz |last3=Pinchuk |first3=Pavel |year=2008 |title=Differential development of breeding plumage in adult and second-year male Ruffs ''Philomachus pugnax'' |journal=Ardea |volume=96 |issue=1 |pages=39–45 |doi=10.5253/078.096.0105|s2cid=86355187 |doi-access=free }}</ref>

<ref name=Khrokov1988>{{cite journal |last=Khrokov |first=V. |year=1988 |title=Breeding record of Ruff ''Philomachus pugnax'' in Northern Kazakhstan |language=ru |journal=Ornitologiya |volume=23 |pages=224–225 }}</ref>

<ref name=Lane1993>{{cite journal |last=Lane |first=Brett |year=1993 |title=Waterbird hunting on the Red River Delta, Northern Vietnam |journal=The Stilt |volume=22 |page=51 |url=https://sora.unm.edu/sites/default/files/journals/iwsgb/n071/p00027-p00029.pdf}}</ref>

<ref name=Lank1987>{{cite journal |last1=Lank |first1=David B. |last2=Smith |first2=Constance M. |date=March 1987 |title=Conditional lekking in ruff (''Philomachus pugnax'') |journal=Behavioral Ecology and Sociobiology |volume=20|issue=2 |pages=137–145 |doi=10.1007/BF00572636|bibcode=1987BEcoS..20..137L |s2cid=29135414 }}</ref>

<ref name=Lank1992>{{cite journal |last1=Lank |first1=David B. |last2=Smith |first2=Constance M. |year=1992 |title=Females prefer larger leks: field experiments with Ruffs (''Philomachus pugnax'') |journal=Behavioral Ecology and Sociobiology |volume=30 |issue=5 |pages=323–329 |doi=10.1007/BF00170598 |bibcode=1992BEcoS..30..323L |s2cid=30368747 }}</ref>

<ref name=Lank1995>{{cite journal |last1=Lank |first1=David B. |last2=Smith |first2=Constance M. |last3=Hanotte |first3=Olivier |last4=Burke |first4=Terry |last5=Cooke |first5=Fred |date=November 1995 |title=Genetic polymorphism for alternative mating behaviour in lekking male ruff ''Philomachus pugnax'' |journal=Nature |volume=378 |issue=6552 |pages=59–62 |url=https://www.sfu.ca/biology/wildberg/nature95.pdf |doi=10.1038/378059a0 |bibcode=1995Natur.378...59L |s2cid=4316628 }}</ref>

<ref name=Lank1999>{{cite journal |last1=Lank |first1=D.B. |last2=Coupe |first2=M. |last3=Wynne-Edwards |first3=K.E. |date=November 1999 |title=Testosterone-induced male traits in female ruffs (''Philomachus pugnax''): autosomal inheritance and gender differentiation |journal=[[Proceedings of the Royal Society B]] |volume=266 |issue=1435 |pages=2323–2330 |url=https://www.sfu.ca/biology/wildberg/Lanketal1999.pdf |doi=10.1098/rspb.1999.0926 |pmc=1690456 }}</ref>

<ref name=Lank2001>{{cite journal |last1=Lank |first1=David B. |last2=Dale |first2=James |year=2001 |title=Visual signals for individual identification: the silent "song" of Ruffs |journal=The Auk |volume=118 |issue=3 |pages=759–765 |url=https://www.sfu.ca/biology/wildberg/lank&dale.pdf |doi=10.1642/0004-8038(2001)118[0759:VSFIIT]2.0.CO;2 |s2cid=41678640 }}</ref>

<ref name=Lank2002>{{cite journal |last1=Lank |first1=David B. |last2=Smith |first2=Constance M. |last3=Hanotte |first3=Olivier |last4=Ohtonen |first4=Arvo |last5=Bailey |first5=Simon |last6=Burke |first6=Terry |year=2002 |title=High frequency of polyandry in a lek mating system |journal=Behavioral Ecology |volume=13 |issue=2 |pages=209–215 |url=https://www.sfu.ca/biology/wildberg/femmate.pdf |doi=10.1093/beheco/13.2.209|doi-access=free }}</ref>

<ref name=lankproject>{{cite web |last=Lank |first=David |title=Ruff Project |url=https://www.sfu.ca/biology/wildberg/ruff.html |publisher=Simon Fraser University |access-date=11 June 2009 }}</ref>

<ref name=Linnaeus1758>{{harvnb|Linnaeus|1758|p=148}}</ref>

<ref name=Lockwood1984>{{harvnb|Lockwood|1984|pp=127–128}}</ref>

<ref name=Lozano2004>{{cite journal |last1=Lozano |first1=G.A. |last2=Lank |first2=D.B. |journal=Animal Biology |volume=54 |issue=4 |pages=315–329 |year=2004 |title=Immunocompetence and testosterone-induced condition traits in male ruffs (''Philomachus pugnax'') |doi=10.1163/1570756042729555}}</ref>

<ref name=Mendes2005>{{cite journal |last1=Mendes |first1=Luisa |last2=Piersma |first2=Theunis |last3=Lecoq |first3=M. |last4=Spaans |first4=B. |last5=Ricklefs |first5=Robert E. |year=2005 |title=Disease-limited distributions? Contrasts in the prevalence of avian malaria in shorebird species using marine and freshwater habitats |journal=Oikos |volume=109 |pages=396–404 |doi=10.1111/j.0030-1299.2005.13509.x |issue=2|bibcode=2005Oikos.109..396M |citeseerx=10.1.1.416.153 }}</ref>

<ref name=Mendes2006>{{cite journal |last1=Mendes |first1=Luisa |last2=Piersma |first2=Theunis |last3=Hasselquist |first3=Dennis |last4=Matson |first4=Kevin D. |last5= Ricklefs |first5=Robert E. |year=2006 |title=Variation in the innate and acquired arms of the immune system among five shorebird species |journal=Journal of Experimental Biology |volume=209 |pages=284–291 |doi=10.1242/jeb.02015 |pmid=16391350 |issue=Pt 2|doi-access=free |bibcode=2006JExpB.209..284M }}</ref>

<ref name=Merrem1804>{{harvnb|Merrem|1804|loc=no.168 col.542}}</ref>

<ref name=Mullarney1999>{{harvnb|Mullarney|Svensson|Zetterstrom|Grant|1999|p=156}}</ref>

<ref name=naturstyrelsen>{{cite web|url=http://www.naturstyrelsen.dk/Naturbeskyttelse/Artsleksikon/Dyr/Fugle/Vadefugle/Brushane/Brushane.htm |title=Brushane |date=15 May 2009 |publisher=[[Danish Forest and Nature Agency]] |language=da |access-date=20 April 2012 |archive-url=https://web.archive.org/web/20120115174802/http://www.naturstyrelsen.dk/Naturbeskyttelse/Artsleksikon/Dyr/Fugle/Vadefugle/Brushane/Brushane.htm |archive-date=January 15, 2012 }}</ref>

<ref name=Payne1984>{{harvnb|Payne|1984|pp=13–14}}</ref>

<ref name=Pearson1981>{{cite journal |last=Pearson |first=D.J. |year=1981 |title=The wintering and moult of ruffs ''Philomachus pugnax'' in the Kenyan Rift Valley |journal=Ibis |volume=123 |issue=2 |pages=158–182 |doi=10.1111/j.1474-919X.1981.tb00922.x }}</ref>

<ref name=Pennant1776>{{harvnb|Pennant|1776|p=460}}</ref>

<ref name=Piersma1997>{{cite journal |last=Piersma |first=T. |year=1997 |title=Do global patterns of habitat use and migration strategies co-evolve with relative investments in immunocompetence due to spatial variation in parasite pressure? |journal=Oikos |volume=80 |issue=3 |pages=623–631 |jstor=3546640 |doi=10.2307/3546640 |bibcode=1997Oikos..80..623P |url=https://pure.rug.nl/ws/files/3216451/1997OikosPiersma.pdf }}</ref>

<ref name=Piersma1998>{{cite journal |last=Piersma |first=Theunis |year=1998 |title=Phenotypic flexibility during migration: optimization of organ size contingent on the risks and rewards of fueling and flight? |journal=Journal of Avian Biology |volume=29 |issue=4 |pages=511–520 |jstor=3677170 |doi=10.2307/3677170|hdl=11370/910b3b48-babf-45ec-aeaf-d62399e5662f |url=https://pure.rug.nl/ws/files/6656673/1998JAvianBiolPiersma2.pdf |hdl-access=free }}</ref>

<ref name=Roulin2004>{{cite journal |last=Roulin |first=Alexandre |year=2004 |volume=79 |title=The evolution, maintenance and adaptive function of genetic colour polymorphism in birds |pages=1–34 |journal=Biological Reviews |doi=10.1017/S1464793104006487 |issue=4 |pmid=15682872 |s2cid=24256187 }}</ref>

<ref name=Simpson1979>{{harvnb|Simpson|1979|p=883}}</ref>

<ref name=Slater1970>{{harvnb|Slater|1970|p=310}}</ref>

<ref name=Snow1998>{{harvnb|Snow|Perrins|1998|pp=628–632}}</ref>

<ref name=Thomas2004>{{cite journal |last1=Thomas |first1=Gavin H. |last2=Wills |first2=Matthew A. |last3=Székely |first3=Tamás |doi=10.1186/1471-2148-4-28 |pmid=15329156 |pmc=515296 |year=2004 |journal=[[BMC Evolutionary Biology]] |volume=4 |page=28 |title=A supertree approach to shorebird phylogeny |doi-access=free }} Figure 7 shows relevant relationships. [https://archive.today/20130802041856/http://www.pubmedcentral.org/articlerender.fcgi?artid=515296%23supplementary-material-sec Supplementary Material]</ref>

<ref name=Threlfall1986>{{cite journal |last1=Threlfall |first1=William |last2=Wheeler |first2=Terry A. |year=1986 |title=Ectoparasites from birds in Newfoundland |journal=Journal of Wildlife Diseases |volume=22 |issue=2 |pages= 273–275 |pmid=3712656 |doi=10.7589/0090-3558-22.2.273|s2cid=27324703 |doi-access=free }}</ref>

<ref name=Trolliet1991>{{cite journal |last1=Trolliet |first1=B. |last2=Girard |first2=O. |year=1991 |title=On the Ruff ''Philomachus pugnax'' wintering in the Senegal Delta |journal=Wader Study Group Bulletin |volume=62 |pages=10–12 |url=http://sora.unm.edu/sites/default/files/journals/iwsgb/n062/p00010-p00012.pdf}}</ref>

<ref name=Trolliet2001>{{cite journal |last1=Trolliet |first1=B. |last2=Girard |first2=O. |year=2001 |title=Numbers of Ruff ''Philomachus pugnax'' wintering in West Africa |journal=Wader Study Group Bulletin |volume=96 |pages=74–78 |url=http://sora.unm.edu/sites/default/files/journals/iwsgb/v096/p00074-p00078.pdf}}</ref>

<ref name=unep>{{cite web |title=Saryarka – steppe and lakes of northern Kazakhstan |work=World heritage sites |url=https://whc.unesco.org/en/list/1102 |publisher=[[United Nations Environment Programme]] and World Conservation Management Centre |access-date=24 March 2016}}</ref>

<ref name=Vaillancourt2005>{{cite journal |last1=Vaillancourt |first1=Eric |last2=Prud'Homme |first2=Sophie |last3=Haman |first3=François |last4=Guglielmo |first4=Christopher G. |last5=Weber |first5=Jean-Michel |year=2005 |title=Energetics of a long-distance migrant shorebird (''Philomachus pugnax'') during cold exposure and running |journal=Journal of Experimental Biology |volume=208 |pages=317–325 |url=http://jeb.biologists.org/cgi/reprint/208/2/317.pdf |doi=10.1242/jeb.01397 |pmid=15634851 |issue=Pt 2 |s2cid=31360687 |doi-access=free |bibcode=2005JExpB.208..317V }}</ref>

<ref name=vanderWal2008>{{cite journal |last1=van der Wal |first1=R. |last2=Palmer |first2=Stephen C. |year=2008 |title=Is breeding of farmland wading birds depressed by a combination of predator abundance and grazing? |journal=Biology Letters |volume=4 |issue=3 |pmid=18381262 |pages=256–258 |url=http://www.abdn.ac.uk/staffpages/uploads/soi668/2008%20Van%20der%20Wal_Palmer%20Biol%20Lett.pdf |pmc=2610041 |doi=10.1098/rsbl.2008.0012 }}</ref>

<ref name=Verkuil2008>{{cite journal |last1=Verkuil |first1=Yvonne I. |last2=Jukema |first2=Joop |last3=Gill |first3=Jennifer A. |last4=Karlionova |first4=Natalia |last5=Melter |first5=Johannes |last6=Hooijmeijer |first6=Jos C.E.W |last7=Piersma |first7=Theunis |date=November 2008 |title=Non-breeding faeder Ruffs ''Philomachus pugnax'' associate according to sex, not morphology: capsule faeders (males that are female look-alikes) associate with males rather than females, at several different spatial scales |journal=Bird Study |volume=55 |issue=3 |pages=241–246 |doi=10.1080/00063650809461529 |doi-access=free }}</ref>

<ref name=Vinicombe1993>{{cite journal |last=Vinicombe |first=Keith |date=May 1983 |title=Identification pitfalls and assessment problems: 4. Buff-breasted Sandpiper ''Tryngites subruficollis'' |journal=[[British Birds (magazine)|British Birds]] |volume=76 |issue=5 |pages=203–206 |url=https://britishbirds.co.uk/wp-content/uploads/article_files/V76/V76_N05/V76_N05_P203_206_A052.pdf}}</ref>

<ref name=Widemo1997>{{cite journal |last=Widemo |first=Fredrik |year=1997 |title=The social implications of traditional use of lek sites in the ruff ''Philomachus pugnax'' |journal=Behavioral Ecology |volume=8|issue=2 |pages=211–217 |doi=10.1093/beheco/8.2.211 |doi-access=free }}</ref>

<ref name=Zockler2002>{{cite journal |last=Zockler |first=Christoph |date=April 2002 |title=Declining Ruff ''Philomachus pugnax'' populations: a response to global warming? |journal=Wader Study Group Bulletin |volume=97 |pages=19–29 |url=http://sora.unm.edu/sites/default/files/journals/iwsgb/v097/p00019-p00029.pdf}}</ref>
}}

==References==
{{Refbegin}}
* {{cite book |last1=Berthold |first1=Peter |last2=Bauer |first2=Hans-Günther |last3=Westhead |first3=Valerie |title=Bird migration: a general survey |year=2001 |publisher=Oxford University Press |isbn=978-0-19-850787-1 }}
*{{cite book | last1 = Birkhead | first1 = Tim | title = The Wisdom of Birds: An Illustrated History of Ornithology | publisher= Bloomsbury | year =  2011| location = London | isbn = 978-0-7475-9822-0}}
* {{cite book |last1=Boere |first1=G.C. |last2=Galbraith |first2=C.A. |last3=Stroud |first3=D.A. |title=Waterbirds around the world |year=2006 |location=Edinburgh |publisher=The Stationery Office |isbn=978-0-11-497333-9 }}
* {{cite book |last1=Cocker |first1=Mark |last2=Mabey |first2=Richard |title=Birds Britannica |year=2005 |publisher=Chatto & Windus |isbn=978-0-7011-6907-7 }}
* {{cite book |last=Coward |first=Thomas Alfred |title=The birds of the British Isles and their eggs |volume=1 |year=1930|publisher=Frederick Warne |edition=4th }}
* {{cite book |editor-last1=del Hoyo |editor-first1=Josep |editor-last2=Elliot |editor-first2=Andrew |editor-last3=Sargatal |editor-first3=Jordi |title=Handbook of the Birds of the World |volume=3: Hoatzin to Auks |year=1996 |location=Barcelona |publisher=[[Lynx Edicions]] |isbn=978-84-87334-20-7 |title-link=Handbook of the Birds of the World }}
* {{cite book |last1=Hayman |first1=Peter |last2=Marchant |first2=John |last3=Prater |first3=Tony |title=Shorebirds: an identification guide to the waders of the world |year=1986 |location=Boston |publisher=Houghton Mifflin |isbn=978-0-395-60237-9 }}
* {{cite book |last1=Liddell |first1=Henry George |author-link=Henry Liddell |first2=Robert |last2=Scott |author-link2=Robert Scott (philologist) |year=1980 |title=A Greek-English Lexicon |edition=Abridged |publisher=[[Oxford University Press]] |location=United Kingdom |isbn=978-0-19-910207-5 |title-link=A Greek-English Lexicon }}
* {{cite book |last=Linnaeus |first=C. |author-link=Carl Linnaeus |title=Systema naturae per regna tria naturae, secundum classes, ordines, genera, species, cum characteribus, differentiis, synonymis, locis. Tomus I. Editio decima, reformata |location=Holmiae [Stockholm] |publisher=Laurentii Salvii |year=1758 |language=la |url=https://archive.org/details/carolilinnaeisys11linn }}
* {{cite book |editor-last=Lockwood |editor-first=W.B. |title=The Oxford Book of British Bird Names |year=1984 |location=Oxford |publisher=Oxford University Press |isbn=978-0-19-214155-2 }}
* {{cite book |last=Merrem |first=Blasius |title=Allgemeine literatur-zeitung |year=1804 |location=Jena |publisher=Halle |language=de }}
* {{cite book |last1=Mullarney |first1=Killian |last2=Svensson |first2=Lars |last3=Zetterstrom |first3=Dan |last4=Grant |first4=Peter |title=Collins Bird Guide |year=1999 |publisher=Collins |isbn=978-0-00-219728-1 }}
* {{cite journal |last=Payne |first=Robert B. |title=Sexual selection, lek and arena behavior, and sexual size dimorphism in birds (ornithological monographs: No. 33) |journal=Ornithological Monographs |issue=33 |pages=1–52 |url=http://sora.unm.edu/node/158 |year=1984 |location=Washington, DC |publisher=American Ornithologists' Union |isbn=978-0-943610-40-5 }}
* {{cite book |last=Pennant |first=Thomas |title=British Zoology |volume=2: Water Birds |url=https://archive.org/details/britishzoology02penn |year=1776 |location=London |publisher=B. White }}
* {{cite book |last=Simpson |first=D.P. |title=Cassell's Latin Dictionary |publisher=Cassell Ltd. |year=1979 |edition=5th |location=London |isbn=978-0-304-52257-6 }}
* {{cite book |last=Slater |first=Peter |title=A field guide to Australian birds: non-passerines |year=1970 |publisher=Rigby |location=Adelaide |isbn=978-0-85179-102-9 }}
* {{cite book |editor-last1=Snow |editor-first1=David |editor-last2=Perrins |editor-first2=Christopher M. |title=The Birds of the Western Palearctic concise edition (2 volumes) |publisher=Oxford University Press |year=1998 |location=Oxford |isbn=978-0-19-854099-1 |title-link=The Birds of the Western Palearctic }}
{{Refend}}

==Further reading==
*{{ cite journal | last=Banks | first=R.C. | year=2012 | title=Classification and nomenclature of the Sandpipers (Aves: Arenariinae) | journal=Zootaxa | volume=3513 | pages=86–88 | url=http://www.mapress.com/zootaxa/2012/f/z03513p088f.pdf | doi=10.11646/zootaxa.3513.1.6 }}
*{{ cite journal | last1=Gibson | first1=R. | last2=Baker | first2=A. | year=2012 | title=Multiple gene sequences resolve phylogenetic relationships in the shorebird suborder Scolopaci (Aves: Charadriiformes) | journal=Molecular Phylogenetics and Evolution | volume=64 | issue=1 | pages= 66–72 | doi=10.1016/j.ympev.2012.03.008 | pmid=22491071 | bibcode=2012MolPE..64...66G }}

==External links==
{{Commons category|Calidris pugnax}}
{{Wikispecies|Philomachus pugnax}}
{{Americana Poster|year=1920|Ruff}}
* [http://sabap2.adu.org.za/docs/sabap1/284.pdf Ruff species text in The Atlas of Southern African Birds]
* [https://web.archive.org/web/20071031231507/http://www.ebc.uu.se/zooeko/FredrikW/Ruff.html Ruff mating strategy introduction and research]
* Ruffs on postage stamps: [http://www.birdtheme.org/species/imagespage.php?spec=1047&fl=P www.birdtheme.org] and {{usurped|1=[https://web.archive.org/web/20001023031741/http://www.bird-stamps.org/cspecies/6208400.htm www.bird-stamps.org]}}
* [https://web.archive.org/web/20141202070120/http://aulaenred.ibercaja.es/wp-content/uploads/191_RuffPpugnax.pdf Ageing and sexing (PDF; 2.0 MB) by Javier Blasco-Zumeta & Gerd-Michael Heinze]
* {{Avibase|name=Calidris pugnax}}
* {{InternetBirdCollection|ruff-philomachus-pugnax}}
* {{VIREO|Philomachus+pugnax|Ruff}}
* {{IUCN_Map|22693468/166259298|Calidris pugnax}}
* {{Xeno-canto species|Philomachus|pugnax|Ruff}}
* {{field guide birds of the world|Philomachus pugnax}}

{{Scolopacidae|1}}
{{Taxonbar|from1=Q28122714|from2=Q26411}}
{{Authority control}}

[[Category:Calidris]]
[[Category:Wading birds]]
[[Category:Birds of Russia]]
[[Category:Birds of Scandinavia]]
[[Category:Wintering birds of Africa]]
[[Category:Birds described in 1758]]
[[Category:Animal taxa named by Carl Linnaeus]]