the stilt sandpiper ( calidris himantopus or micropalama himantopus ) is a small shorebird .

the scientific name is from ancient greek .

the genus name kalidris or skalidris is a term used by aristotle for some grey-coloured waterside birds .

the specific himantopus means " strap foot " or " thong foot " .

this sandpiper bears some resemblance to the smaller calidrid sandpipers or " stints " .

dna sequence information is incapable of determining whether it should be placed in calidris or in the monotypic genus micropalama .

it appears most closely allied with the curlew sandpiper , which is another aberrant species only tentatively placed in calidris and could conceivably be separated with it in erolia .

the stilt sandpiper breeds in the open arctic tundra of north america .

it is a long-distance migrant , wintering mainly in northern south america .

it occurs as a rare vagrant in western europe , japan and northern australia .

this species nests on the ground , laying three or four eggs .

the male has a display flight .

outside the breeding season , this bird is normally found on inland waters , rather than open coasts .

this species resembles the curlew sandpiper in its curved bill , long neck , pale supercilium and white rump .

it is readily distinguished from that species by its much longer and paler legs , which give rise to its common and scientific names .

it also lacks an obvious wing bar in flight .

breeding adults are distinctive , heavily barred beneath , and with reddish patches above and below the supercilium .

the back is brown with darker feather centres .

winter plumage is basically gray above and white below .

juvenile stilt sandpipers resemble the adults in their strong head pattern and brownish back , but they are not barred below , and show white fringes on the back feathering .

these birds forage on muddy , picking up food by sight , often jabbing like the dowitchers with which they often associate .

they mainly eat insects and other invertebrates .

stilt sandpiper

the oldest recorded stilt sandpiper was at least 11 years , 1 month old , when it was recaptured and rereleased during banding operations in texas .
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hill , c . 2006 . first record of a stilt sandpiper ( micropalama himantopus ) in new zealand . notornis 53 : 320 - 321 . urltoken
jehl jr . , j . r . 1973 . breeding biology and systematic relationships of the stilt sandpiper . wilson bulletin 85 : 115 - 147 .
jamieson , s . e . 2013 . stilt sandpiper . in miskelly , c . m . ( ed . ) new zealand birds online . urltoken
in its boldly barred breeding plumage , the stilt sandpiper is easily identified . in its gray nonbreeding plumage , it is much less distinctive and appears to be intermediate between a yellowlegs and a dowitcher .
the stilt sandpiper is much like most other calidridine sandpipers . it has typical sandpiper morphology and structure ( e . g . , long bill , long legs , and pointed wings ) , and both its juvenile and adult plumages are similar to the other calidris sandpipers . even behaviourally it is a conventional sandpiper - it is a gregarious , long distant migrant . on the arctic breeding grounds male stilt sandpipers conduct acrobatic aerial territorial displays , a behaviour observed in many other sandpipers ( e . g . , dunlin , and least , semipalmated and western sandpipers ) . however , recent genetic evidence suggests that the stilt sandpiper does not belong to the genus calidris , but rather it is a close relative .
similar species : the downward curvature of the bill could lead to confusion with curlew sandpipers and some subspecies of dunlin ( e . g . , c . alpina pacifica ) , but the stilt sandpiper has long , greenish legs , while both the curlew sandpiper and dunlin have black legs . under poor lighting , the yellowy - green legs of a juvenile stilt sandpiper might lead one to think of dowitchers ( limnodromus scolopaceus or l . griseus ) or yellowlegs ( tringa flavipes or t . melanoleuca ) but neither group has a downward - curved bill .
during the non - breeding season stilt sandpipers feed primarily on a wide variety of freshwater aquatic invertebrates , supplemented by occasional seeds .
klima , j . and jehl jr , j . r . ( 1998 ) stilt sandpiper ( calidris himantopus ) in : poole , a . ( ed . ) the birds of north america online . cornell lab of ornithology , ithaca . available at : urltoken
the female stilt sandpiper is usually slightly larger than the male ( 2 ) , while juveniles are browner than the adult , with pale scaling on the back , a buffy , thinly - streaked neck and breast , white underparts and sometimes yellowish legs ( 2 ) ( 4 ) ( 5 ) ( 7 ) . the calls of the stilt sandpiper include a quiet , scratchy kirrr or krrit ( 3 ) ( 4 ) , a longer , scratchy song , usually given in flight , and a rhythmical , repeated urreee ( 3 ) ( 5 ) .
myers jp : cross - seasonal interactions in the evolution of sandpiper social systems . behav ecol sociobiol . 1981 , 8 : 195 - 202 .
klima , j . ; jehl jr . , j . r . 2012 . stilt sandpiper ( calidris himantopus ) , the birds of north america online ( a . poole , ed . ) . ithaca : cornell lab of ornithology ; retrieved from the birds of north america online : urltoken
the stilt sandpiper is a small shorebird that prefers to breed in arctic regions of open tundra in north america . in winter months , this species will migrate long distances southward to south america and rarely western europe . nests are built on the ground , and three to four eggs are laid each year . when not in breeding season , the natural habitat of the stilt sandpiper includes inland waters rather than open coastlands . this species is so named due to the long , skinny legs with which is wades through the shallow ocean waters near the coast . the conservation rating is currently least concern .
stilt sandpipers are usually found in small mixed flocks ( < 22 birds ) and feed in shallow waters , often with the water reaching their bellies .
stilt sandpipers breed in the coastal regions of western northwest and yukon territories ( canada ) and northern alaska ( usa ) . they winter primarily in the interior of central south america ( brazil , peru , bolivia , paraguay , and argentina ) . there are about 5 records of stilt sandpipers from australia .
stilt sandpiper : breeds from northeastern alaska to northeastern manitoba and northernmost ontario . spends winters in south america and casually north to florida and southern california . preferred habitats include sedge meadows interrupted by old beach ridges , eskers , or other elevated areas dominated by dwarf birch , heaths , willows , crowberries , and dryads .
stilt sandpipers nest as close as 12 feet to other shorebirds , but at least 900 feet from their own kind , probably as a defense against predators .
the main southward migration route of the stilt sandpiper passes through the middle of the continent , west of the mississippi river . from here , in fall the species migrates over water to the caribbean or northern south america , where many birds interrupt their migration to molt flight feathers before continuing to winter haunts in inland central south america .
the stilt sandpiper is an unusual shorebird , market gunners once knew it as the “bastard yellowlegs” as it was thought to be in between a yellowlegs and a dowitcher . in non - breeding plumages this is not far from the truth to the field observer . in some situations a stilt sandpiper can become lost in a group of dowitchers , foraging in the typical sewing machine motion , while in other situations it can be on par with a yellowlegs and very similar to it in many ways including having long yellowish legs . it also resembles the winter curlew sandpiper , and even a winter wilson’s phalaropes . it is such a mix of features that the stilt sandpiper is difficult to define , and at one time was put into its own genus . only in breeding plumage is it truly distinctive , with a boldly barred underpart pattern and rusty on the cap and the cheek . stilt sandpipers sometimes winter in the southern united states , and they winter uncommonly in mexico and central america ; by far the main wintering region is the interior of south america , south of the amazon basin . it is not a coastal species there , but more likely to be found in inland ponds , habitats where pectoral sandpipers may also be found . more work is needed to determine where the most important wintering areas are for this generally low density shorebird .
often described as looking like a yellowlegs and feeding like a dowitcher , the stilt sandpiper is a medium - sized , long - legged wader . its breeding plumage is distinctive , but rarely seen in washington . it is heavily barred brown - and - white above and below , with a white eye - line that separates a rufous cap and cheek . in non - breeding plumage , the stilt sandpiper is pale gray , with a light , unstreaked belly and white eye - line . juveniles are light brownish - gray with lightly streaked breasts and scaled backs . in flight , they show gray and white underwings , solid gray upperwings , white rumps , and gray tails .
christidis l , davies k , westerman m , christian pd , schodde r : molecular assessment of the taxonomic status of cox ' s sandpiper . condor . 1996 , 98 : 459 - 463 .
this wader is related to our very smallest sandpipers , but it is much more stretched - out in shape , designed for feeding in deeper water . in its drab winter plumage the stilt sandpiper is often overlooked , passed off as either a yellowlegs or a dowitcher , depending on what it is doing . standing or walking , it looks rather like a yellowlegs ; feeding , it acts like a dowitcher , probing the mud with a sewing - machine motion .
stilt sandpipers eat a wide variety of insects and insect larvae during the breeding season . at other times of the year , they eat seeds , leaves , and roots of aquatic plants , marine worms , and other aquatic invertebrates .
stilt sandpipers are rare in puget sound and coastal washington from mid - june through september , with occasional sightings before and after . in eastern washington , they are rarely reported from early july through september , with scattered later sightings .
there are no specific conservation measures currently known to be in place for the stilt sandpiper ( 5 ) , although it is listed on appendix ii of the convention on migratory species ( cms or bonn convention ) , which aims to protect migratory species throughout their range ( 9 ) . further research and survey work has been recommended , and the species may also benefit from investigations into the effects of land use changes on its wintering populations in south america ( 5 ) .
] and is found in our supertree . the supertree resolves the thinocoridae and pedionomidae as sister taxa and this group is sister to the jacanidae and rostratulidae . the large scolopacidae clade is at the base of the sandpiper clade consistent with recent molecular studies [
large flocks of stilt sandpipers are common in areas where they are abundant , but in washington , single birds or a few birds are generally seen mixed with flocks of dowitchers or lesser yellowlegs . stilt sandpipers usually forage in shallow water up to their bellies . they probe in the mud for food , often moving their heads up and down , sometimes under water , in a sewing - machine motion like that of a dowitcher . they also pick food from the surface of the water .
the stilt sandpiper has a widespread distribution and large population , and is not currently considered at risk of extinction ( 8 ) . the species is not known to face any major threats ( 2 ) , although it may be affected by habitat loss and degradation in some areas . for example , overgrazing by geese opens up nesting habitat on the tundra , making eggs and chicks more vulnerable to predators , while substantial land use changes potentially affect the species’ wintering habitat in south america ( 5 ) ( 7 ) .
in north america , sixty - five species of sandpipers , phalaropes and allies in eighteen genera have occurred . included among these birds are the large , long - billed godwits and curlews , the harlequin - like ruddy turnstone , and a variety of sandpiper species .
the stilt sandpiper breeds in arctic and subarctic areas of north america , from northern alaska east to james bay , canada , and migrates south to spend the winter mainly in inland central south america . smaller numbers overwinter in scattered locations in the southern united states , central america and the caribbean ( 2 ) ( 3 ) ( 5 ) ( 6 ) , and the species is also occasionally recorded outside of its normal range , in europe , japan , taiwan , china and australia ( 4 ) ( 5 ) ( 8 ) .
the stilt sandpiper is a medium - sized wader . in non - breeding plumage , it has brown - grey upperparts ( head , neck , mantle , wings ) , grey sides that smudge into a whitish belly , a white rump and grey tail . it also has a distinctive whitish supercilium ( eyebrow ) and no wing bars . the dark - coloured bill is long relative to its body size and it has a slight downward curve . the long legs can be various shades of green , juveniles have legs that tend to be yellowy - green .
stilt sandpipers ' breeding grounds are in the arctic tundra , north of the tree line . they nest in wet sedge - meadows with raised ridges and hummocks . during the non - breeding season , they are usually found in fresh water ponds , marshes , lagoons , and flooded fields .
this species breeds primarily in sedge tundra near water , often close to the wooded borders of taiga ( 2 ) ( 3 ) ( 5 ) ( 7 ) . although preferring to nest near to the coast , it may also nest further inland during years when snowmelt occurs late ( 3 ) . in winter and during migration , the stilt sandpiper feeds mainly in freshwater or brackish marshes , flooded fields , shallow pools and ponds , and coastal lagoons . mudflats and tidal flats are sometimes used , but more rarely than by most related species ( 2 ) ( 3 ) ( 5 ) ( 7 ) .
the canadian wildlife service estimates the population of stilt sandpipers at 200 , 000 birds . populations in some areas have declined , while others have increased . the range - wide status of the population is unknown . this species has a limited and disconnected breeding range , and degradation of some of that habitat is of conservation concern . changes in land use on south american wintering grounds are also of concern , because some winter gathering spots are being developed . stilt sandpipers are listed on the partners in flight watch list because of their narrow breeding and wintering distributions , relatively small population , and unknown trends in population .
the stilt sandpiper usually feeds alone or in small groups , often associating with other waders such as the lesser yellowlegs ( tringa flavipes ) and dowitchers ( limnodromus species ) ( 2 ) ( 3 ) ( 6 ) . individuals typically wade in belly - deep water , frequently with the head submerged , moving forward slowly and searching for prey by rapid probing with the beak , often described as a ‘sewing - machine’ action ( 2 ) ( 3 ) ( 5 ) ( 6 ) . prey may also be taken from the water’s surface or sometimes from dry land , and includes a variety of invertebrates , particularly adult and larval insects , as well as snails and also seeds ( 2 ) ( 3 ) ( 5 ) .
sandpipers , phalaropes and allies occur in a wide variety of aquatic habitats that include mudflats , beaches , shores of ponds , lakes and rivers , and marshes although two members of the family , the long - billed curlew and upland sandpiper , are grassland birds . most members of this family breed in the extensive wetlands of the arctic tundra , utilizing other wetland habitats during migration and winter .
three main lineages are revealed : i ) the plovers and allies ; ii ) the gulls and allies ; and iii ) the sandpipers and allies . the relative position of these clades is unresolved in the strict consensus tree but a 50 % majority - rule consensus tree indicates that the sandpiper clade is sister group to the gulls and allies whilst the plover group is placed at the base of the tree . the overall topology is highly consistent with recent molecular hypotheses of shorebird phylogeny .
the majority of sandpipers , phalaropes and allies occur in flocks outside of the breeding season . they can often be seen foraging in mixed flocks for a variety of invertebrates and crustaceans , each species searching for food in a different manner or in different habitats . for example the least sandpiper probes just below the mud at water’s edge , dowitchers probe deep into the mud further out in the water , and the greater yellowlegs chases small fry with its bill held below the surface of the water .
a slender , medium - sized wading bird with distinctively long , spindly legs , the stilt sandpiper is also readily recognised by its long neck and long , blackish beak , which is slightly down - curved and wider at the tip ( 2 ) ( 3 ) ( 4 ) ( 5 ) ( 6 ) . during the breeding season , the dark upperparts of the body are heavily barred with reddish - brown and white , and the face bears a chestnut cheek patch below a white ‘eyebrow’ stripe . the rest of the body is barred greyish - brown and white , the rump is white , and the long legs are usually greenish , with slight webbing at the base of the front toes . the non - breeding plumage is much less distinctive , being brownish - grey above , white below , and greyish on the throat and chest , although the white eyebrow stripe remains conspicuous ( 2 ) ( 4 ) ( 5 ) ( 6 ) ( 7 ) .
the nest of the stilt sandpiper is an unlined scrape on the ground , usually located in relatively open , dry tundra , on a small hummock , gravel ridge or on flat ground . the species is monogamous and breeding pairs may reuse the same nest for more than one year ( 2 ) ( 5 ) . breeding usually takes place between early june to mid - july ( 2 ) ( 3 ) . four eggs are usually laid and are incubated by both the male and female , hatching after 19 to 21 days . the young sandpipers are well developed , leaving the nest soon after hatching , and are even able to cross pools and slow - flowing streams as the adults lead them to feeding areas . the chicks are able to feed themselves and are left by the adults after just one to two weeks . the female leaves earlier than the male , well before the young fledge at around 17 to 18 days old , and also departs the breeding grounds first , with the males leaving about a week later . juveniles follow from around mid - august ( 2 ) ( 3 ) ( 5 ) . most immature birds are likely to spend the following summer in the wintering grounds ( 2 ) ( 3 ) , not migrating north to breed until the second year ( 5 ) .
stilt sandpipers generally don ' t breed until they are two years old . males arrive on the breeding grounds a few days before females . pairs form once the females arrive . the male makes a few scrapes in a dry spot on the ground , often on a ridge or hummock of sedge , surrounded by water . the female then chooses one of the scrapes for the nest . the nest may be sparsely lined with sedge leaves . both parents incubate the four eggs for 19 to 21 days . the young leave the nest within a day of hatching and find their own food . both parents tend the young at first , but the female usually leaves within seven days . the male stays with the young for 10 to 14 days , but abandons the young before they can fly well , at 17 to 18 days . each pair raises only one brood per season .
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cramp , s . and simmons , k . e . l . ( eds ) . 1977 - 1994 . handbook of the birds of europe , the middle east and africa . the birds of the western palearctic . oxford university press , oxford .
justification : 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 increasing , 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 .
anguilla ; antigua and barbuda ; argentina ; aruba ; bahamas ; barbados ; belize ; bermuda ; bolivia , plurinational states of ; brazil ; canada ; cayman islands ; chile ; colombia ; costa rica ; cuba ; dominica ; dominican republic ; ecuador ; el salvador ; falkland islands ( malvinas ) ; french guiana ; grenada ; guadeloupe ; guatemala ; guyana ; haiti ; honduras ; jamaica ; martinique ; mexico ; montserrat ; nicaragua ; panama ; paraguay ; peru ; puerto rico ; saint barthélemy ; saint kitts and nevis ; saint lucia ; saint martin ( french part ) ; saint vincent and the grenadines ; sint maarten ( dutch part ) ; suriname ; trinidad and tobago ; turks and caicos islands ; united states ; uruguay ; venezuela , bolivarian republic of ; virgin islands , british ; virgin islands , u . s .
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order charadriiformes ( shorebirds ) is an ideal model group in which to study a wide range of behavioural , ecological and macroevolutionary processes across species . however , comparative studies depend on phylogeny to control for the effects of shared evolutionary history . although numerous hypotheses have been presented for subsets of the charadriiformes none to date include all recognised species . here we use the matrix representation with parsimony method to produce the first fully inclusive supertree of charadriiformes . we also provide preliminary estimates of ages for all nodes in the tree .
the supertree hypothesis presented herein is ( to our knowledge ) the only complete phylogenetic hypothesis of all extant shorebirds . despite concerns over the robustness of supertrees ( see discussion ) , we believe that it provides a valuable framework for testing numerous evolutionary hypotheses relating to the diversity of behaviour , ecology and life - history of the charadriiformes .
] ) present an exceptional group for studying numerous evolutionary hypotheses . their remarkable diversity of social mating system , parental care , sexual dimorphism , ecology and life - history make them an ideal group for unravelling the mechanisms of , for example , sexual selection and sexual conflict . previous comparative studies have made significant contributions to our understanding of the evolution of mating systems [
] . however , the shorebird studies listed above were limited by the lack of a complete phylogeny for the group . most of these studies are based on derivations of the seminal work of sibley and ahlquist [
] , yet this study included less than a quarter of extant and recently extinct shorebird species . recently extinct taxa ( according to monroe and sibley [
] data suggests that they are a highly derived sister group to stercorariini ( skuas and jaegers ) , larini ( gulls ) , sternini ( terns ) , and rynchopini ( skimmers ) . it is important to note that taxon coverage differs between these studies and this may be an important factor in determining the tree topology . specific phylogenies have been derived , for example , for sandpipers [
] using dna sequence data . in contrast , morphological evidence provided the basis for chu ' s [
] presented the most complete data set of 227 charadriiformes species . however , despite the plethora of cladograms for particular shorebird groups ( see reviews by sibley and ahlquist [
previous hypotheses shorebird phylogeny . family and subfamily level relationships of shorebirds based on : a ) morphological data [ 19 ] ; b ) dna - dna hybridisation [ 16 ] ; c ) sequence analysis of rag - 1 [ 20 , 21 ] , cytochrome - b [ 22 ] and myoglobin intron ii [ 21 ] .
numerous methods and types of data can be used to infer phylogeny . frequently , as in charadriiformes , a single analysis incorporating all taxa of interest is absent . under the principle of total evidence [
] , all sources of phylogenetic information should be combined to maximize their explanatory power . eernisse and kluge [
] define total evidence as a method for seeking the best fitting phylogenetic hypothesis for an unpartitioned set of synapomorphies ( shared derived characters ) using character congruence ( characters combined in a supermatrix ) . hence , this method combines the primary data ( molecular , morphological and behavioural characters ) into a single analysis . the approach is powerful because weak signals in the partitioned data sets may be enhanced when combined , and previously obscured relationships may be revealed [
the total evidence approach has both practical and theoretical problems . first , only certain types of data can be combined . for example , nucleotide sequences and morphological traits can be readily assessed together as characters , but it is not generally possible to include nucleotide sequences and genetic distance data in a single analysis [
] suggest a distance based approach to combine otherwise incompatible data in a total evidence analysis , although this method has not been tested beyond a single application . the consequence is that it is rarely possible to combine all sources of data in practice and the lack of overlap in combinable data sets may result in a reduction of the number of taxa included . second , miyamoto and fitch [
] contend that combining data sets is rarely justified because partitions of phylogenetic data are real and unequivocal . they argue that several partitions producing similar topologies provide multiple lines of independent evidence supporting that topology .
exclusion of certain data types . this is particularly true of charadriiformes phylogeny , where one of the most significant contributions to the field – dna - dna hybridisation – cannot be included . an alternative set of techniques , collectively termed supertrees ( e . g . , matrix representation with parsimony , mrp ; [
] ) , enables combination of trees ( rather than raw data ) from otherwise incompatible sources . mrp methods code source phylogenies based on the presence and absence of taxa at each node of the tree [
] and are thus one step removed from the primary data . it is important to recognise that supertrees should not be regarded as a replacement for exhaustive phylogenetic studies of the primary data and there are drawbacks to the methods ( see discussion ) . however , they do enable very large phylogenies to be constructed rapidly [
shorebirds are particularly well suited for supertree treatment , since there are numerous incomplete phylogenies available and a broader phylogeny is desirable to facilitate powerful analyses of numerous evolutionary hypotheses ( see above ) . here , we present the first complete composite phylogeny of extant and recently extinct [
] shorebirds using the mrp approach . we are therefore combining data on tree topologies , and not conducting a simultaneous analysis on the original data . we also use fossil and molecular data to estimate divergence times ( see methods ) . the combination of complete taxonomic coverage and the inclusion of branch lengths provide the basis for future comparative analyses of charadriiformes evolution . in addition , conflicting and unresolved areas of charadriiformes phylogeny are revealed .
we found 1469 equally short trees of length 1847 steps using the parsimony ratchet approach ( see methods ) . this compares favourably to a standard heuristic search that yielded shortest trees of 1853 steps . all subsequent results and discussion refer to the parsimony ratchet analyses . figure
show the species level phylogeny . the full 50 % majority rule consensus and the strict consensus trees are available as
respectively . the 50 % majority - rule consensus tree is well resolved ( 73 . 1 % ; 255 nodes out of a possible 349 in a fully bifurcating tree ) , although the strict consensus tree is only 49 . 6 % resolved ( 173 from 349 possible nodes ) . the majority rule tree includes nine novel clades ( numbers 20 , 29 , 57 , 85 , 89 , 108 , 122 , 139 , 140 ) that do not appear in any of the source trees ; all of these occur towards the tips of the tree . this is a general problem in supertree construction and such clades should be collapsed as they have no support [
] . to demonstrate where the mrp method has performed badly we have included the novel clades in all figures and list details in the figure legends . in addition , 58 nodes are supported by only one character ( see
) . each of these nodes is left over from a single source tree . assessing the support for such nodes is problematic because this may simply reflect a lack of research directed at the taxa in question . a major challenge for supertree construction is to develop measures of support that reflect the robustness of nodes in the source trees . we list the number of characters supporting each node (
) but stress that these are not measures of tree robustness and may not be directly comparable even within the same tree . this is because the taxon coverage across source trees is highly variable so some nodes have more potential support than others . furthermore , because measures of support used in the source trees differ between studies ( some source trees include no measures of support ) , it is impractical and of dubious value to use these measures to assess the robustness of the supertree .
summary of shorebird supertree . family and subfamily level relationships of shorebirds based on 50 % majority rule tree . numbers on nodes refer to age estimates in additional file 1 . boxed node numbers indicate that node collapses to its immediate ancestor in the strict consensus tree ( see also additional files 2 and 3 for the full 50 % majority rule and strict consensus trees respectively ) .
phylogeny of larini . 50 % majority rule supertree showing the relationships of the larini . numbers on nodes refer to age estimates in additional file 1 . boxed node numbers indicate that node collapses to its immediate ancestor in the strict consensus tree ( see also additional files 2 and 3 for the full 50 % majority rule and strict consensus trees respectively ) .
phylogeny of sternini . 50 % majority rule supertree showing the relationships of the sternini . numbers on nodes refer to age estimates in additional file 1 . boxed node numbers indicate that node collapses to its immediate ancestor in the strict consensus tree ( see also additional files 2 and 3 for the full 50 % majority rule and strict consensus trees respectively ) .
, alcinae , and glareolidae . numbers on nodes refer to age estimates in additional file 1 . boxed node numbers indicate that node collapses to its immediate ancestor in the strict consensus tree ( see also additional files 2 and 3 for the full 50 % majority rule and strict consensus trees respectively ) . node numbers 139 and 140 have no support from any source tree and are novel clades .
phylogeny of jacanidae , rostratulidae , thinocoridae , pedionomidae and scolopacidae 50 % majority rule supertree showing the relationships of the jacanidae , rostratulidae , thinocoridae , pedionomidae and scolopacidae . numbers on nodes refer to age estimates in additional file 1 . boxed node numbers indicate that node collapses to its immediate ancestor in the strict consensus tree ( see also additional files 2 and 3 for the full 50 % majority rule and strict consensus trees respectively ) . node numbers 85 and 89 have no support from any source tree and are novel clades .
phylogeny of scolopacidae 50 % majority rule supertree showing the relationships of the scolopacidae . numbers on nodes refer to age estimates in additional file 1 . boxed node numbers indicate that node collapses to its immediate ancestor in the strict consensus tree ( see also additional files 2 and 3 for the full 50 % majority rule and strict consensus trees respectively ) . node numbers 108 and 122 have no support from any source tree and are novel clades .
phylogeny of pluvianellidae , chionidae , burhinidae , haematopodini and recurvirostrini 50 % majority rule supertree showing the relationships of the pluvianellidae , chionidae , burhinidae , haematopodini and recurvirostrini . numbers on nodes refer to age estimates in additional file 1 . boxed node numbers indicate that node collapses to its immediate ancestor in the strict consensus tree ( see also additional files 2 and 3 for the full 50 % majority rule and strict consensus trees respectively ) . node numbers 20 and 29 have no support from any source tree and are novel clades .
phylogeny charadriinae 50 % majority rule supertree showing the relationships of the charadriinae . numbers on nodes refer to age estimates in additional file 1 . boxed node numbers indicate that node collapses to its immediate ancestor in the strict consensus tree ( see also additional files 2 and 3 for the full 50 % majority rule and strict consensus trees respectively ) . node number 57 have no support from any source tree and are novel clades .
the majority of unresolved nodes in the shorebird supertree are located towards the tips of the phylogeny . for example , the genus
) in the majority - rule tree . only the latter relationship remains in the strict consensus tree . in addition , clades including the genera
are poorly resolved . this may reflect a bias in phylogenetic studies of shorebirds . for instance , we found six source trees for alcinae [
] indicate that this may be a problem for shorebird studies in general and reported a strong skew favouring research on northern hemisphere species .
in contrast to the within genera relationships , the generic and family levels are generally well resolved . the supertree indicates three monophyletic charadriiformes lineages ( figure
) . family and subfamily resolution within each lineage is high , however the relative position of each group is unresolved in the strict consensus tree . this is an important point because the deepest relationships of shorebird phylogeny are contentious [
, alcinae , and glareolidae ) are sister to the sandpipers and allies ( scolopacidae , jacanidae , rostratulidae , thinocoridae , pedionomidae ) . the most basal lineage includes the plovers and allies ( charadriinae , pluvianellidae , chionidae , burhinidae , haematopodini and recurvirostrini ) . the gulls and allies clade is most consistent with dna - dna hybridisation [
] , indicating that larini are sister to sternini and that rynchopini are sister to this group . this conflicts with morphology - based topologies where stercorariini are sister to larini and sternini with rynchopini basal to both . indeed , the position of stercorariini remains controversial and most recently they were placed as sister to alcinae [
] places alcinae at the base of the whole charadriiformes tree with stercorariini sister to larini . thus , the position of alcinae is uncertain and appears to be dependent on the type of data , with fundamental differences between molecular based analyses and morphological analyses . the taxon sampling of previous morphological and molecular studies varies considerably and it may be this , rather than genuine differences in the phylogenetic signal of different data types , that is the cause of conflict in resolving the phylogenetic position of alcinae . however , it is encouraging that van tuinen
] suggested that new unpublished osteological data are consistent with the more derived position indicated by molecular data . the supertree resolves glareolidae outside the larini , sternini , rynchopini , stercorariini ,
, alcinae clade . this is also the case with recent molecular and previous dna - dna hybridisation studies . morphological studies have failed to resolve the position of glareolidae , placing the family in a large polytomy with all other major groups except alcinae and the sandpipers and allies ( fig .
] . we did not include this species in the supertree because to date paton et al . [
] remains the only study to reveal an apparently robust relationship . more diverse sampling of the buttonquails ( turnicidae ) is essential to corroborate the general affinities of this family .
the relationships within the plover clade appear to be reasonably stable . morphological , molecular , and dna - dna hybridisation all place charadriinae as sister to haematopodini and recurvirostrini ; our supertree is consistent with these relationships . however , it is not clear whether burhinidae and chionidae are sister to each other [
) and places this as sister to chionidae . if pluvianellidae are excluded , the supertree is consistent with the sister group relationship of burhinidae and chionidae .
taken together , it is evident that the supertree is generally more consistent with molecular data ( both recent sequence studies and dna - dna hybridisation ) than with analyses based on morphology . however , it is of course possible that this reflects the greater number of molecular source trees available rather than indicating that molecular data is actually better at resolving shorebird phylogeny . we included several large morphological phylogenies [ e . g [
the higher resolution of the majority - rule tree means it is more likely to be of use in comparative studies . we therefore estimated node ages for this topology only ( see
) . we stress that our estimates of node dates are a first attempt at dating the whole tree and have several limitations . first , the fossils used to calibrate seven nodes in the tree are unlikely to be the earliest members of their respective families thus these dates will be underestimates . second , we assumed that the fossils are grouped with the extant members of the family but this requires formal testing in a phylogenetic framework . third , the pure birth model assumes that no extinction occurs but this may be unrealistic and it is likely that extinction processes have reduced the representation of older lineages [
] . furthermore , this model is derived from the topological structure of the tree so errors in tree reconstruction will likely lead to errors in branch length estimation . however , this approach has been employed previously in supertrees of primates [
] explicitly to facilitate comparative analyses . despite these caveats , simulation studies have demonstrated that comparative methods such as independent contrasts are robust to errors in branch length [
] and no viable alternative for dating supertrees has been proposed . nonetheless , we urge that alternative branch length assumptions are explored if the shorebird supertree is used in future comparative studies . at present , the calibrated rag - 1 tree of paton et al . [
] remains arguably the most thorough and reliable measure of divergence times for charadriiformes .
a fuller understanding of the phylogenetic affinities of fossil shorebirds will probably improve estimates of node ages for the group . for example , the extinct form graculavidae , is represented by fossils from the maastrichtian of new jersey [
] suggests that it may be basal and a formal corroboration of this would support proposals for a late cretaceous origin of shorebirds . the difficulties in dating the shorebird tree are further illustrated by fossil representatives of recurvirostrini and burhinidae which are much older than current estimates suggests . the earliest record of the recurvirostrini is estimated to be over 50 million years old [
] . there is clearly a need for an integrated phylogenetic study including both extinct and extant shorebirds .
supertrees are still at an early stage of development and many aspects of mrp , and supertree methods in general , are not yet clearly understood . steps can be taken to ensure that the supertree includes the most appropriate sets of sources trees , such as only using trees from explicitly phylogenetic studies . this is not always straightforward and could result in the exclusion of important information . for instance , in our shorebird supertree , we included sibley and ahlquist ' s dna - dna hybridisation tapestry [
] although this is based on distance measures rather than more rigorous phylogenetic methods . even if very strict tree selection criteria are applied , there are still likely to be biases in the data set . for example , not all source trees are equally well supported , yet in most supertree analyses each tree is treated equally [
] it is rarely possible in practice . many source trees do not have support values and those that do may use different methods , ( e . g , bootstrapping or decay indices ) which cannot be directly compared with each other . an additional problem that has not been fully resolved relates to correlations between source trees [
] . several source trees based on the same data set may unduly increase the influence of that data set on the supertree analysis . however , there is no formal way of determining how much overlap to allow and the choice of source trees that go into supertree construction inevitably involves some degree of subjective reasoning . for the shorebird supertree we used strict reduced cladistic consensus trees to summarise potential source trees that were from the same data set but based on different methods . for example , thomas
but used a range of methods including parsimony and bayesian analyses . we therefore combined these trees to minimise bias . in contrast , ericson
] used two types of data : sequences from the nuclear rag 1 gene and sequences from the myoglobin intron ii . they carried out three analyses : each gene separately and then the two combined in a single analysis . in this case , we used three source trees . it could be argued that the combined analysis of ericson
] should be excluded because of the possible overlap with the individual analyses . however , under the principle of total evidence , the combined data set may result in novel relationships being revealed [
] and therefore could contribute important information to the supertree . simulation and empirical studies are required to fully understand these and other possible biases in supertree construction ( e . g . , the influence of source tree size and shape ) and formal protocols for the selection of source trees are desirable . for transparency , we include a summary of the source trees used , data type , and the main taxa included in the study (
our shorebird supertree is highly consistent with recent advances in the molecular phylogenetics charadriiformes . however , we urge caution when using the tree in comparative analyses and encourage the additional use of alternative phylogenies and branch length assumptions . it is particularly important to note that the position of some groups such as the alcinae remains controversial and that although the majority rule tree is consistent with recent molecular studies , the strict consensus tree fails to resolve the deepest nodes .
the supertree presented here is , to our knowledge , the first attempt to reconstruct the phylogeny of the entire order charadriiformes . overall , the supertree is highly consistent with recent molecular hypotheses of shorebird phylogeny . however , it is apparent that fresh attempts to resolve both the phylogeny and estimates of age will be dependent on further gene sequencing and new fossil discoveries . the affinities of the alcinae and the relationships between the three major shorebird clades require further corroboration , and studies of several genera such as gallinago and vanellus are desirable . furthermore , additional work is required to establish the true affinities of the turnicidae . nonetheless , it appears that shorebird phylogeny is gradually approaching a consensus view . the broad taxonomic scope and consistency of the supertree mean that is of potentially great value to future comparative studies ( accepting the caveats discussed above ) of the behaviour , life - history , ecology and conservation of this diverse group .
covering the years 1981 to 2004 . we used the single key strings phylogen * , cladistic * , clado * , classif * , systematic * , and taxonom * ( where the asterisks allow variations such as
phylogeny
or
phylogenetics
) in the topic field , in conjunction with a major charadriiformes taxon name ( scientific or common ) . as supertree methods have been criticized for being biased towards historical trends , we preferred those studies that explicitly set out to derive a phylogenetic hypothesis and so exclude purely ( and typically older ) descriptive taxonomic works . the sibley and ahlquist [
] dna - dna hybridisation tapestry may be viewed as non - cladistic , but it was clearly the authors ' intention to reconstruct the phylogeny of birds . furthermore , it provided a vital catalyst for subsequent studies of avian ( including shorebird ) phylogeny . we therefore included the dna - dna hybridisation hypothesis as a source tree in our analyses . simulation studies have demonstrated that the performance of supertree methods is improved by including at least one taxonomically complete ( or near complete ) source tree [
] as a source tree as this includes all extant charadriiformes species . we acknowledge that this taxonomy is based largely on sibley and ahlquist ' s [
the initial search identified 78 source trees from 44 publications . each source tree was typed as a text file in nexus format [
] , we use charadriiformes not charadrii to refer to the whole group . several studies included the gull
] ) or a species in its own right . in recognition of this , we included
as the only subspecies in our data set thus increasing the total taxa to 366 . monroe and sibley [
] include 16 species of the family pteroclidae within the charadriiformes . however , the relationship of this family to the charadriiformes is uncertain and they have recently been placed in their own order [
] . we include the pteroclidae in our analyses only as a means of rooting the tree . where there were multiple most parsimonious trees ( mpts ) , or where source trees had been derived from predominantly overlapping data ( e . g . , from the same data but using alternative methods ) , we used radcon [
for the mrp file ) . we used the original mrp coding method of baum [
] . the absence of branch support measures in many of the shorebird source trees precludes this approach from the present study ; hence , subsequent analyses were conducted using equally weighted parsimony .
the tendency of large data sets to produce many sub - optimal trees that are close in length and topology to the shortest tree is a serious problem in phylogenetics . standard heuristic searches frequently are trapped searching within globally sub - optimal
islands
and the tree search is often aborted before completion . nixon [
] proposed a new method to avoid this problem . the
parsimony ratchet
reweights a random set of characters from the data set . this may result in the tree island no longer representing a local optimum and the heuristic search continues until a new optimum is reached . the algorithm then reverts to the original weighting and the search continues . nixon [
] demonstrated the efficacy of the method on a 500 - taxon data set , where the ratchet - based search found a tree two steps shorter than standard heuristic searches . we used pauprat [
] . the default settings of 200 iterations and 15 % perturbation of characters for reweighting were used and we carried out 20 replicates . equally parsimonious trees were summarized using both strict and 50 % majority - rule consensus methods .
we did not calculate any measures of branch support for two reasons . first , their validity and meaning is questionable in mrp supertrees [
] . second , the number of taxa included in our data set is too large to allow practical calculation of any branch support indices ( e . g . , decay indices [
] we dated the supertree using both absolute and relative dates . we used data from the fossil record 2 [
] as the source of fossil - based absolute dates . this yielded estimates for jacanidae (
sp . , middle miocene ) , and larini ( undetermined , rupellian ) . we took the midpoint of the range from the fossil record 2 [
] as our date estimate . more recent publications of fossil charadriiformes were not included because they either represent specimens that are younger or have not been assigned to families that are represented amongst the extant charadriiformes ( such as turnipacidae [
] ) . we assumed that fossil dates represent the earliest occurrence for each group which inevitably resulted in underestimates of clade age . the fossil record of charadriiformes is amongst the best of the modern bird groups [
] . the phylogenetic affinities of the fossil shorebirds in relation to their extant relatives have not yet been fully established , hence have implicitly assumed that fossil representatives of extant groups would be resolved amongst their living relatives .