Ringed Plovers Research Articles

Little Ringed PloversCharadrius dubiusin Britain in 1984

The 1984 census revealed that the population of Little Ringed Plovers summering in Britain had increased by approximately 30% since 1973 to a minimum of 608 pairs, thus continuing the upward trend which began in the 1940s. There was an extension of range westwards and an expansion within the northern part of the existing range. The population changed very little in the south, where it is possible that the available habitat is now fully occupied, although interaction with Ringed Plovers Charadrius hiaticula¸ may be a limiting factor in places. Some concern must he expressed for the long-term future of the species in Britain as it depends largely on man-made habitats, free of vegetation, for breeding.

Wader populations on the non-estuarine coasts of Britain and Northern Ireland: results of the 1984–85 Winter Shorebird Count

The wintering wader populations of the non-estuarine coasts of Britain, the Isle of Man, the Channel Isles and Northern Ireland were surveyed in December 1984 and January 1985. The total length of such coasts is 13525 km, compared with 4315 km of estuarine shores. Approximately 90% of the non-cliff shores outside the estuaries was surveyed and almost 300000 waders of 19 species were recorded. The highest densities were found around the Irish Sea, NE England and SE Scotland, while very low densities were recorded for much of south and SE England, the Shetland Islands, and the mainland west coast of Scotland. Oystercatchers, Curlews, Turnstones, Dunlins and Redshanks were the most abundant species. With the exception of Dunlins, these were also the most frequently encountered species. The effects of the severe weather which occurred during the latter half of the survey were analysed using repeat counts. There were no detectable effects on the populations of Oystercatchers, Ringed Plovers, Turnstones, Curlew...

A revision of population estimates for waders (Charadrii) wintering on the coastline of Britain

Abstract Recent surveys have revealed that approximately 1·3 million waders winter on the British coastline. Dunlin Calidris alpina , oystercatcher Haematopus ostralegus and knot Calidris canutus were the most abundant species, together making up two-thirds of the total. More than 80% of the waders were found on estuaries, although these habitats comprise less than one-quarter of the coastline, by length; furthermore, more than 50% of the waders occured, in mid-winter, on only ten estuaries. The patterns of dispersion varied between species. The estuaries supported all or most of the national populations of black-tailed godwit L. limosa , knot, dunlin, bar-tailed godwit Limosa lapponica and grey plover Pluvialis squatarola , whilst purple sandpiper Calidris maritima , turnstone Arenaria interpres , ringed plover Charadrius hiaticula and sanderling Calidris alba were typically non-estuarine shore species. The winter populations of black-tailed godwit, bartailed godwit, knot, oystercatcher and dunlin are concentrated into a few estuaries, while the other species are more dispersed. The implications of these patterns are discussed with respect to estuarine habitat loss. The revised population estimates were similar to those from earlier studies for five species, were lower for two species, and were higher for five species. New values are recommended for use in ornithological site assessments, based on the criterion of 1% of the national population. The delimitation of sites, for such evaluations, is discussed.

Spring migration of birds across the Greenland Inlandice

Radar observations from a long-range surveillance station in SE Greenland (65°31'N, 37°08'W) during the end of May and beginning of June 1980 and 1982, demonstrated regular bird migration across the Inlandice in both E/SE and W/NW directions. According to supplementary field observations from SE and W Greenland 1980, -82 and -84, and to available information from the literature, the most probable species to carry out a transglacial E/SE-migration in spring are Gavia immer, Clangula hyemalis, Mergus serrator, Anas platyrhynchos and, possibly, Alle ,alle and Larus hyperboreus. These birds probably depart from the ice-free coasts in W Greenland towards breeding sites along the E Greenland coast and, at least in Clangula hyemalis, Iceland and possibly even further to the east. Plectrophenax nivalis and Calcarius lapponicus probably also travel eastwards over the southern Inlandice to SE Greenland breeding sites.
 Species involved in the transglacial W/NW-migration comprise geese, Anser albifrons and Branta bernicla, and high arctic waders, Charadrius hiaticula, Arenaria interpres, Calidris canutus and Calidris alba. In addition, it is highly probable that also Oenanthe oenanthe, Sterna paradisaea and Phalaropus lobatus belong to this category.
 The geese and high arctic waders depart from staging areas in Iceland to undertake a long-distance flight to breeding grounds in W Greenland (Anser albifrons) or NW Greenland and N Canada. The flight route passes the Sermilik fjord region in SE Greenland, where the migrants shift from a W/WNW course over the Denmark Strait to a WNW/NW course across the Inlandice.
 The route from Iceland via Sermilik to NW Greenland and N Canada is about 10% longer than the great circle route across the central and northern Inlandice. However, wind conditions for a high altitude transglacial flight are much less favourable along the great circle route. The observed migration patterns involve the crossing of 450-700 km of inlandice, reaching 2500-2800 m asl, with temperatures about -10°C. The total flight distance from Iceland to NW Greenland and N Canada is 2300-3000 km.
 Staging areas for ducks and divers along the Greenland west coast, and for geese and waders in Iceland, are probably of crucial importance for the evolution of the observed transglacial migration patterns. The distance from Iceland to the northernmost part of the Nearctic is smaller than from corresponding spring staging sites in North America. Hence, Iceland serves as a spring-board to Nearctic breeding grounds for Old World winter populations of waders and geese. Staging sites probably have a dual effect as spring-boards and bottle-necks, respectively, for the evolution of migration patterns in arctic birds. Gaps in the circumpolar breeding distribution of arctic species, and a relatively low diversity of species breeding in the sector around Greenland, may be due to competition for limited staging resources in combination with the isolating effects in this sector of sea expanses and the Greenland Inlandice.

The origins and destinations of waders using the coasts of Suffolk and Essex

Origins and destinations of 10 species of waders using the Suffolk/Essex coast have been determined from reports of ringed birds, as part of an assessment of the impact of reclamation on the Orwell estuary. Most species occur both during migration periods, especially autumn, and in winter. Wintering populations breed in northwest Europe (Oystercatcher, Ringed Plover, Dunlin, Bar‐tailed Godwit, Curlew, Redshank), Siberia (Grey Plover, Dunlin, Bar‐tailed Godwit), Iceland (Redshank) and Greenland/Canada (Knot, Sanderling, Turnstone). Autumn and spring populations of Oystercatchers, Ringed Plovers, Grey Plovers, Sanderlings, Curlews, Redshanks and Turnstones are of similar breeding origins to their wintering populations, but additionally include Dunlins from Iceland, Knots from Siberia and probably Ringed Plovers from Iceland.

The distribution and local movements of shorebirds within the Moray Firth

SynopsisThe shorebird populations of the Moray Firth mudflats were studied between 1981 and 1985. Peak numbers of waders were found in midwinter when the total population may exceed 36,000 birds. More than 1% of the total northwest European population of oystercatchers (Haematopus osiralegus), redshank (Tringa totanus), bar-tailed godwit (Limosa tapponica) and knot (Calidris canutus) were recorded. Wildfowl reach peak numbers in October and November (approximately 45,000); numbers decline gradually thereafter as some birds move on to wintering sites elsewhere in Britain. Ringing and colour-marking studies showed that turnstone (Arenaria interpres), curlew (Numenius arquata), ringed plover (Charadrius hialicula), oystercatcher and redshank remained loyal to selected feeding areas within the Moray Firth while bar-tailed godwit, knot and dunlin (Calidris alpina) ranged widely throughout the winter.These observations are discussed in relation to the value of the Moray Firth to shorebirds and the problems posed by the reclamation of intertidal habitats and pollution of the intertidal areas.

Populations of breeding waders charadrii and their habitats on the crofting lands of the outer hebrides, Scotland

The islands in the southern half of the Outer Hebrides (the Southern Isles) hold very high densities of six species of breeding waders. The waders are largely confined to the Atlantic fringes where there are large deposits of shell-sand. This coastal strip is a complex of dry and wet habitats, dominated by level sandy plains (machair). Transition grassland (blackland) exists between the machair and the peatlands of the interior. Surveys in 1983 and 1984 showed that waders were distributed at high density throughout most of the 186 km 2 of machair and blackland of the larger islands: the overall density of waders exceeded 80 pairs km −2 but the average density in some habitats exceeded 200 pairs km −2. Nowhere else in Britain supports a similar assemblage of species of breeding waders. The density of waders is unique in Britain for such a large area of land. The Southern Isles support approximately a quarter of the British population of ringed plovers Charadrius hiaticula and as much as a third of Britain's breeding dunlins Calidris alpina. The Southern Isles are amongst the most important breeding grounds for waders in the north-west Palearctic. Internationally they represent a particularly important habitat for the southern dunlin C. alpina schinzii and the densities of C. hiaticula are probably the highest in Europe.

Raptor predation on wintering waders in southeast Scotland

Predation on waders was investigated over the winters of 1982‐83 and 1983‐84 at a rocky shore and a small estuary in southeast Scotland. Probably all the waders which were found after being eaten were killed by raptors; mammalian predation and death due to severe weather were of minimal importance in comparison to the effects of raptor predation. Sparrowhawks were probably the major predators of waders at both sites, but owls also took some. Differences were found between the rocky shore and the estuary in the species of raptors which were seen (more Peregrines and Merlins seen on the estuary) and in the numbers of wader kills which had been plucked and eaten on open ground (more open ground pluckings, indicative of Peregrines and Merlins, found on the estuary). It is suggested that Peregrines and Merlins took more waders at the estuary due to their preference for hunting over large open expanses. Winter mortality rates due to predation varied in different species of waders: at the rocky shore the Redshank suffered the heaviest winter mortality (20% and 16%) whilst on the estuary the Ringed Plover had the highest winter mortality (19%). At both sites no large waders such as Curlews and Oystercatchers died as a result of predators and for these species other factors, such as severe weather or starvation, appeared to be a greater source of mortality. Significantly more juvenile Redshanks, Turnstones and, probably, Dunlin and Ringed Plovers were found eaten than was expected from the age‐composition of their respective populations. In the Redshank and Turnstone several differences in the behaviour of juveniles and adults were discovered which may have made juveniles more vulnerable to predation.

Behaviour of young Ringed Plovers Charadrius hiaticula and its relationship to growth and survival to reproductive age

The behaviour, growth and survival of Ringed Plover chicks were studied in 1974 at Mestersvig, northeast Greenland, and from 1973 to 1976 at Lindisfarne, northeast England. Post‐fledging survival, dispersal and recruitment were also investigated for the Lindisfarne population.Growth rates were similar in both study areas, and to those reported from other sites. A diurnal rhythm in feeding activity was more evident in the Arctic than at temperate latitudes, despite continuous daylight in the former area. This was correlated with low nocturnal temperatures and prey availability. It is concluded that food supply did not limit growth or chick survival in either study area. Brooding decreased progressively during the pre‐fledging period; the relationship of brooding period to age, environmental conditions and area was investigated. The adaptations of feeding and brooding behaviour for arctic and temperate breeding Ringed Plovers are discussed.Survival from hatching to fledging varied between 40% and 60% in different areas and years, and at least 59% of birds survived from fledging to about one year old. Minimum survival from one to two years old was only 57%. but year‐to‐year survival of older birds was higher, that of breeding adults being at least so?;. Most birds returned to the breeding area and attempted to breed when one year old. The extent of dispersal from Lindisfarne and the wintering areas of the Lindisfarne‐breeding birds are investigated.

Breeding biology and population dynamics of Ringed plovers Charadrius hiaticula in Britain and Greenland: nest‐predation as a possible factor limiting distribution and timing of breeding

The nesting of Ringed plovers was investigated in 1974 at Mestersvig, north‐east Greenland, and in 1974–76 at Lindisfarne, north‐east England. Difficulties in the use of Nest Record Cards for this species (to obtain information from more sites) are discussed. Territory sizes tended to be smaller, and more feeding took place within territories, at Lindisfarne than at Mestersvig. Clutch sizes were similar in different areas. Incubation (mean period about 25 days) was shared fairly equally by the two sexes. Longer incubation shifts at Mestersvig and some areas at Lindisfarne than at other Lindisfarne sites were associated with greater distances between nests and feeding areas. Most egg losses were probably due to predation, and were fewer in the Arctic than in Britain, where nesting success varied greatly in different areas and years, and in relation to timing within a season. Up to five nestings per pair per year were made at Lindisfarne, but only one at Mestersvig.The timing of breeding is discussed, and it is concluded that the date of start of egg‐laying in north‐east Greenland is determined by the timing of snow clearance, while that at Lindisfarne is related to the decreasing probability of egg‐predation later in the season. Because of the high nest losses, the production of young at many temperate sites, including parts of Lindisfarne, was probably inadequate for the population to be self‐supporting. The reasons for the large seasonal, annual and geographical differences are discussed. It is concluded that increasing predation probably determines the southern nesting limits of Ringed plovers, but that this limit may be modified by varying degrees of different types of natural and artificial protection, and extent of habitat suitable for egg camouflage. Increased human usage of nesting beaches probably has an adverse effect on nesting success, but because of the complexity of the number of inter‐related factors affecting the latter, without field experiments it is difficult to predict how this could best be offset by protection measures.

The distribution and reproduction of Ringed Plovers breeding coastally and inland in north-west England

The distribution and reproduction of Ringed Plovers breeding coastally and inland in north-west England

Changes in the foraging pattern of plovers in relation to environmental factors

The effects of environmental conditions on the foraging behaviour of ringed and grey plovers ( Charadrius hiaticula and Pluvialis squatarola) were investigated at Lindisfarne National Nature Reserve, Northumberland. Plovers forage by an apparently visual searching technique, scanning an area while standing still, before running to peck at prey. Plovers appeared to select large prey, in suitable conditions, by not responding to cues of small prey at the start of each waiting period. Within a waiting period, they became progressively more ready to take smaller prey, before eventually giving up and moving to a new waiting site. Giving-up time was adjusted to different conditions, resulting in the selection of larger prey when prey availability was high, notably at high temperatures. The birds tended to concentrate their activity on clumps of high density of available prey, by moving less far after taking large prey than after taking small or no prey. When no prey was taken after a wait, the bird moved on sufficiently far to scan a new area, or further in areas of low-density, highly clumped prey. In addition to feeding by day, plovers also forage at night. Night observations of foraging behaviour and performance are presented, and discussed in relation to visual foraging and the increased activity of some intertidal invertebrates at night. Although plovers apparently use visual searching, for which the prey detection ranges are probably shorter at night, they were able to maintain fairly high pecking rates at night, partly because of higher surface activity levels of prey.

Surface activity of some intertidal invertebrates in relation to temperature and the foraging behaviour of their shorebird predators

Effects of environmental conditions on the behaviour of the prey animals of Ringed and Grey Plovers Charadrius hiaticula and Pluvialis squatarola were investigated in the field at Lindisfarne National Nature Reserve, Northumberland. England. The plovers detected and caught prey by watching for, and exploiting, the brief periods of surface activity. The cues used include cast production by Arenicola marina, outflows of water from the holes of Notomastus latericeus and other polychaetes, and swimming movements by small amphipods and isopods. The intertidal polychaetes A. marina and N. latericeus, the amphipod Bathyporeia pelagica and the isopod Eurydice pulchra increased their surface activity in relation to variations in environmental conditions, particularly warmer temperatures. When activity of the surface-living small Crustacea was low, Ringed Plovers used foot-vibration to stimulate movement of these animals, making them visible.

Diet and energy intake of Grey and Ringed plovers, Pluvialis squatarola and Charadrius hiaticula, in the non‐breeding season

The diets, feeding rates, foraging times during daylight, the extent of nocturnal feeding and food intakes of Grey and Ringed plovers Pluvialis squatarola and Charadrius hiaticula are described or estimated from field observations, checked by ciné‐film, in Northumberland, England, from autumn to spring of the years 1973–76. (Gut analysis was unreliable as a quantitative guide to diet.) Main prey at Lindisfarne for both plovers were the polychaete worms Notomastus, Arenicola and probably Scoloplos and Phyllodoce and, for Ringed plovers, also various small Crustacea, particularly Bathyporeia and Eurydice. Comparisons with diets of the same species elsewhere showed that they are not specialized but vary their diet in accordance with the prey species common in a particular area. In autumn and spring, but not in winter, food requirements could be met during daylight. An increase in the percentage of the daylight hours spent feeding in winter was inadequate to compensate for the decreases in both hours of daylight and feeding rate which occur at this season. Both plovers were able to feed at night, but, on dark nights at least, at a slower rate than by day. High winds apparently depressed the extent of nocturnal feeding. In mid‐winter, the birds maintain high fat levels, probably to buffer the effects of days when they have difficulty in obtaining their energy requirements, such as during cold and windy weather. Because plovers' feeding rates are reduced more by low temperatures than those of waders foraging by touch, their rates of energy intake fall more in such conditions. An attempt is made to predict the minimum densities of prey required for energy balance in various conditions and to compare the foraging strategies of visually foraging plovers and tactilely‐foraging sandpipers.

Observations on waders (Charadriidae) at Scoresby Sund, East Greenland

Populations of waders in three census areas at Scoresby Sund, central East Greenland, were studied during the three breeding seasons of 1973, 1974 and 1975. Ringed Plover (Charadrius hiaticula ), Golden Plover (Pluvialis apricaria), Turnstone (Arenaria interpres), Knot (Calidris canutus), Dunlin (Calidris alpina) and Sanderling (Calidris alba) bred in the census areas, while Purple Sandpiper (Calidris maritima) and Red-necked Phalarope (Phalaropus lobatus) bred elsewhere in the region. Population densities were very low, compared to other areas further north in high arctic Greenland. Extensive, deep and late-thawing snow cover prevents waders from utilizing large areas in June. Time of breeding showed a high correlation with the snow melting conditions in the respective areas and years. Breeding success was generally low; only Ringed Plover had more than 50% nest and egg survival. Nest failures were probably mostly due to predation by Arctic Foxes (Alopex lagopus). Observation and examination of individuals from post-breeding flocks in the second half of July indicated that these flocks contained mainly non-breeders, but failed and successful breeders were also present. Measurements on eggs, pulli and adults are presented.

Autumn passage of ringed plovers through Southampton water

Autumn passage of ringed plovers through Southampton water

SEASONAL VARIATIONS IN THE MASS OF WADERS IN SOUTHERN AFRICA, WITH SPECIAL REFERENCE TO MIGRATION

Summary Summers, R. W. & Waltner, M. 1978. Seasonal variations in the mass of waders in southern Africa, with special reference to migration. Ostrich 50:21-37. Seasonal variations in the mass of various wader species are described from data collected mainly in the southwestern Cape from 1970 to 1977. 1Y+ (older than one year) Turnstones Arenaria interpres, Ringed Plovers Charadrius hialicula, Great Sandplovers C. leschenaultii, Grey Plovers Pluvialis squatarola, Knots Calidris canutus Sanderlings C. alba, Terek Sandpipers Xenus cinereus. Common Sandpipers Tringa hypoleucos, March Sandpipers T. stagnatilis, Greenshanks T. nebularia, Bartailed Godwits Limosa lapponica and Whimbrels Numenius phaeopus showed an increase in mass between late March and early May. This was associated with the accumulation of fat deposits as measured in Turnstones and Sanderlings. 1Y-t-Turnstones, Knots and Sanderlings had their smallest mass in mid summer (December and January). Ruffs Philomachus pugnax had a slight rise in mass...

Birds of the Outer Hebrides: the waders

SynopsisThe wading bird communities of four major habitat zones are described. Shore habitats support few breeding birds but hold significant numbers of migrant and wintering waders. Oystercatcher, ringed plover, bar-tailed godwit and dunlin are the most numerous species on the sand flats; the Atlantic beaches are particularly important to turnstones, purple sandpipers and sanderling. The wintering sanderling population is of national significance. Densities of breeding waders on the machair are greater than elsewhere in Britain. The dominant species are oystercatcher, ringed plover, lapwing and dunlin. The machair is nationally outstanding for breeding ringed plovers and the Outer Hebrides supports 14% of the British and Irish population. The machair is also unique in Britain for its concentration of coastal breeding dunlin. At other times of the year flocks of lapwings, golden plovers and curlew feed on the machair. Rough grazing (blackland) inland from the machair supports high densities of breeding snipe and redshank. Large numbers of grassland plovers and snipe feed here in winter. Seven species breed on the uplands and peatlands: golden plover, snipe, curlew, whimbrel, common sandpiper, greenshank and dunlin. Most of these species are more abundant north of the Sound of Harris and the north Lewis moors hold relatively high densities of golden plovers and dunlin.

The Ringed Plover Populations of Morecambe Bay

Large numbers of Ringed Plovers pass through Morecambe Bay in spring, believed bound for Greenland. In autumn, when numbers are smaller, two separate stocks are involved: a moulting population drawn from temperate Europe (some of which overwinter), and birds of arctic origins which pause to put on weight but do not moult there.

Breeding Populations of Ringed Plovers and Dunlins in the Uists and Benbecula, Outer Hebrides

Some 780–950 pairs of Ringed Plovers and 310–375 pairs of Dunlins breed in these three Outer Hebridean islands, representing significant proportions of their British breeding populations. Habitat preferences are discussed.