Ruddy Turnstone Arenaria Interpres Research Articles

First estimates of Common Sandpiper <i>Actitis hypoleucos</i> and Ruddy Turnstone <i>Arenaria interpres</i> wintering along the coast of Trapani (Sicily, Italy)

A census was carried out using the method of transects along stretches of coast of the Province of Trapani in order to estimate the wintering population of Common Sandpiper and Ruddy Turnstone. Although the International Waterbird Census (IWC) provides accurate estimation of wintering waders in Italy, the number of wintering individuals of Common Sandpiper Actitis hypoleucos and Ruddy Turnstone Arenaria interpres are strongly underestimated. The reason for this underestimation lies in the type of habitat they are used to populate along with the solitary life habits of the Common Sandpiper. To address this issue, we inspected 46.9 km of coastline where we recorded to 92 Ruddy Turnstones and 56 Common Sandpipers. For both species, the sites (coast) where bird-sightings occurred were marked with georeferenced data and classified as harbour area, sandy, rocky (including vermetid reefs) and posidonia banquettes. For each species, the IKA (Index of Abundance per Kilometer) was calculated, both global index and relative to each type of coast. As for the Common Sandpiper we observed 87 individuals, between transects and spot observations in the province of Trapani, which is the 22% of the whole wintering population estimated in Italy. Notably, even greater is the importance of our observations of the Ruddy Turnstone, which accounting for up to 154 individuals corresponds to the 71% of the whole Italian wintering population. Projection of these data to the entire Italian coast allows estimating a wintering population in Italy much larger than that reported so far, especially for the Common Sandpiper, which uses not only the sea cost but also inland wetlands and rivers as suitable wintering habitats for wintering.

Arnthor Gardarsson 1938–2022

Professor Arnthor Gardarsson (1938–2022) was an Icelandic ornithologist who made a major contribution to the studies of the bird fauna of Iceland and to the ecology of waterfowl and wetland conservation. After finishing a BSc in Zoology from the University of Bristol in 1962 he went to the University of California, Berkeley, for a PhD project under the supervision of Professor Frank A. Pitelka. His project, finished in 1971, was about the population and feeding ecology of the Icelandic Ptarmigan Lagopus muta islandorum. In 1971–73, working with the Icelandic Museum of Natural History, he conducted a research programme on the ecology of the Thjorsarver area. This tundra oasis in the otherwise desert-like Icelandic highlands harboured the world's largest breeding colony of the Pink-footed Goose Anser brachyrhynchus and was under serious threat by hydropower development. A part of this ecosystem-oriented study involved aerial surveys of birds, a method that was to become one of Arnthor's signature research tools. Waterfowl held a special place in Arnthor's heart. The opportunity to study them in detail came in 1974 when Lake Myvatn, the world-renowned waterfowl site in Iceland, was defined as a nature reserve. This was in the wake of a heated debate over a hydropower project that would have fundamentally altered the lake's ecology. In 1974, Arnthor became professor in zoology at the new biology department of the University of Iceland and he promptly focused his academic research effort on Lake Myvatn. The idea was to monitor the ecological situation of the lake by studying its many duck populations. Despite the newly acquired protection status, there was concern about ongoing industrial sediment extraction from the lake (continuing till 2004). Arnthor's efforts, with students and collaborators, soon developed into a full-scale ecological study of the lake's foodweb, benefiting from his deep insight into ecological processes. His research revealed immense fluctuations in the Lake Myvatn ecosystem, that still occur and continue to attract scientific interest. The studies resulted in a series of classic papers, demonstrating how the variable abundance of aquatic insects and crustaceans in a lake determined duckling production and subsequent changes in breeding populations. It was Arnthor's ambition to obtain a comprehensive picture of the bird populations of Iceland, their distribution, size, production, resources, and trends. It was a gargantuan task, considering the size, remoteness and ruggedness of the landscape and the sheer number of birds. But Arnthor was a daredevil who was quick to apply aerial surveys to the mapping and photographing of all the important bird areas, both coastal and inland, and he kept seeking new techniques to this effect. Estimating bird densities in the immense, towering seabird colonies of northwest Iceland was his biggest challenge. His final solution was to fly low over and then off the cliff edge, taking a rapid succession of photographs with a large-format camera aimed slightly backwards – a rather risky undertaking with the myriad of fast-flying birds around. His aerial endeavours, backed up by field studies, resulted in comprehensive population estimates of alcids, Black-legged Kittiwakes Rissa tridactyla, Northern Fulmars Fulmarus glacialis, Northern Gannets Morus bassanus, European Shags Gulosus aristotelis, Great Cormorants Phalacrocorax carbo, Common Eiders Somateria mollissima and other ducks, swans, geese and even passing migratory waders such as Red Knots Calidris canutus, Ruddy Turnstones Arenaria interpres and Sanderlings Calidris alba. Later he extended the surveying to cover all the Atlantic Puffin Fratercula arctica colonies of Iceland and developed methods to monitor seabird trends via ground-based observations. Arnthor also used his skills to reveal the details of the population dynamics of European Shags and Great Cormorants in the Breidafjördur archipelago, their central stronghold in Iceland. Spring field trips with his students to the impressive seabird colonies in the northwest of Iceland made an enduring impact on many, who are now continuing and expanding the monitoring work on birds in marine, freshwater and terrestrial habitats all over Iceland. Arnthor served as a chairman of the Nature Conservation Council in 1990–96, a government advisory body that also managed protected areas. Through this he became a leading figure in the protection of many of the ecosystems he had studied, in particular Thjorsarver and Myvatn, the crown jewels of inland wetland sites in Iceland. In addition to his extensive ornithological skills, Arnthor had a fascination for terrestrial and marine invertebrates, polychaetes in particular, and he was proficient in botany. He was also artistic and made a name for himself at a young age when illustrating papers on bird life. Arnthor's character may be described as an attractive mix of generousity, ambition and shyness, as well as being humble, friendly and joyful. In 1959 Arnthor married Gudrun Sveinbjarnardóttir (1937–2016), an economist from Reykjavik. They had two children, Soffia and Thrandur.

Over-summering shorebirds at the Kerala coasts, west-coast of India

Over-summering is a phenomenon usually exhibited by migratory shorebirds. Those individuals that over-summer at their wintering grounds appear to be sexually immature or unfit to meet the risks of migration. Documentation of such migratory shorebirds are scanty along the Indian coasts and the present study focused on recording the over-summering shorebirds at five sites (Kappad Beach, Korappuzha Beach, Elathur Beach, Ariyallur Beach and Kadalundi-Vallikkunnu Community Reserve) along the west coast of India during 2021–2022. Over-summering shorebird species were identified and documented once in a week using a binocular, a spotting scope and a 4 K high speed motion latest video camera. Six species of over-summering shorebirds (Lesser Sand Plover Charadrius mongolus, Greater Sand Plover Charadrius leschenaultii, Pacific Golden Plover Pluvialis fulva, Whimbrel Numenius phaeopus, Common Sandpiper Actitis hypoleucos and Ruddy Turnstone Arenaria interpres) were recorded from the five study areas and their abundance were observed to be declining during the study period.

Species‐specific demographic and behavioral responses to food availability during migratory stopover

AbstractUnderstanding the effects of migratory stopover site conditions on both demographic rates and migratory behaviors is critical for interpreting changes in passage population sizes at stopover sites and predicting responses to future changes and conservation actions. We used a Bayesian formulation of the open robust design model to analyze mark‐resight observations of three migratory shorebird species using Delaware Bay, USA during spring stopover from 2005 to 2018. We tested for an effect of stopover food availability and weather conditions on survival probability and the probability of returning to this site in the next year and found species differences in these relationships. After years with greater food availability, red knot Calidris canutus rufa had higher survival probability but ruddy turnstone Arenaria interpres were more likely to return to the site. Estimates of within‐year probabilities of arrival and persistence at the stopover site showed relatively consistent migration schedules for ruddy turnstone, but more interannual variation for red knot and sanderling Calidris alba. Shorebird use of this site typically peaked during May 26–28, but the estimated proportion of the population present during this period varied dramatically among years for red knot (range: 0.07–0.59) but less so for ruddy turnstone and sanderling. This demonstrates that both the proportion of the flyway population using this stopover site and the proportion present during a given sampling period vary among years, and both should be considered in analyzing and interpreting monitoring data. Stopover conditions can influence both migratory behavior and demographics, underscoring the importance of flyway‐wide monitoring.

Offshore refuges support higher densities and show slower population declines of wintering Ruddy Turnstones Arenaria interpres: a response

ABSTRACT In this reply, we confirm that the results of the original paper are robust and that our conclusions were correct: densities of Ruddy Turnstones Arenaria interpres were lower on sites located further from undisturbed refuges. There are two points of learning here: (i) taking the findings of a paper based purely on what is published is normal but there is an unpublished iterative process for analysis that is often hidden from a reader (described here), so we refute that our results were caused by chance; (ii) we published a result based on an incorrect method in the revision process. We hope that other researchers involved in long-term projects involving large and complex datasets can learn from our mistake, as we will endeavour to do.

Offshore refuges support higher densities and show slower population declines of wintering Ruddy Turnstones Arenaria interpres: a comment on the log-transformation of bird densities

ABSTRACT Log transformations of density values in the form log(count)/log(area), as used in a recent paper in this journal, do not preserve the rank order of the untransformed density values and are dependent on the units used for area. The appropriate log transformation of density is log(count/area).

Offshore refuges support higher densities and show slower population declines of wintering Ruddy Turnstones Arenaria interpres

ABSTRACTCapsule: Wintering Ruddy Turnstones Arenaria interpres occur in higher densities and their populations decline less on, or close to, offshore refuges than on mainland sites subject to greater levels of human disturbance.Aim: To compare wintering densities of Ruddy Turnstones and changes in counts across time from sites with differing levels of human disturbance.Methods: Long-term counts of Ruddy Turnstones (1998/1999 to 2015/2016) were used from 19 sites (two offshore refuges and 17 mainland sites subject to higher levels of human disturbance) in northeast England. No direct measure of human disturbance was available for our mainland sites; instead we used questionnaires (n = 690) to understand how far people travelled to visit the coast and then used this distance with human population densities in a buffer around each site as a proxy for human disturbance levels.Results: After controlling for the extent of their preferred habitat at each site (rocky shore) we found: (i) the closer each of the 19 sites was to the nearest offshore refuge the higher the density of Ruddy Turnstones and (ii) bird counts were stable at the two refuge sites, whereas, on average, counts declined at the 17 mainland sites. However, no relationship was found between Ruddy Turnstone counts from 17 mainland sites and human population densities within differing distances from each site (up to 10 km).Conclusions: Our work suggests that Ruddy Turnstones made greater use of relatively undisturbed areas (offshore refuges) than those subject to greater disturbance by humans (mainland sites). Although the use of refuges and mainland in our study area was not well known, observations from 11 radio-tagged Ruddy Turnstones suggest that individual birds did use both locations. In a broader context, our work concurs with other studies that highlight the need for refuges with limited or no human access.

The identity of two of Azara’s “mystery” waterbirds

The identity of two birds described from Paraguay by Félix de Azara as No. 378 “Ypacahá jaspeado encima” and No. 402 “Chorlito pies roxos” is elucidated for the first time. No. 378 refers to Ocellated Crake Micropygia schomburgkii and is the basis for the name Rallus maculosus of Vieillot, 1819. Rallus maculosus Vieillot, 1819, is a nomen oblitum, unavailable for application. No. 402 is referable to Ruddy Turnstone Arenaria interpres morinella and is the basis of the name Totanus nigellus Vieillot, 1816. Totanus nigellus Vieillot, 1816 is thus a junior synonym of Arenaria interpres morinella (Linnaeus, 1766) and available for application.

Moorland Point: Decline of a traditional roost-site for Ruddy Turnstone Arenaria interpres, Pacific Golden Plover Pluvialis fulva and other shorebirds in northern Tasmania

The Moorland Point area has been an important high-tide roost for certain migratory shorebird species on the central-north coast of Tasmania, where shorebirds are generally scarce. Ruddy Turnstone Arenaria interpres and Pacific Golden Plover Pluvialis fulva roost on a small rocky headland and adjacent piles of seaweed along with up to three Grey-tailed Tattlers Tringa brevipes (all mainly in summer), and Double-banded Plover Charadrius bicinctus roost above the high-tide mark 250 m to the east (mainly February–early August). More than 300 counts of shorebirds have been made at this site from 1985 to 2014. All these species have declined in recent years. Ruddy Turnstone, Pacific Golden Plover and Grey-tailed Tattler may have been affected by factors elsewhere in the East Asian–Australasian Flyway, but local disturbance is also implicated and needs further management in addition to the recent initiative to block vehicles from the beach. The situation highlights some of the problems in conserving shorebird species that favour scattered small sites and may escape the attention given to sites supporting large numbers of more social shorebirds.

Habitat Choice and Niche Characteristics Under Poor Food Conditions. A Study on Migratory Nearctic Shorebirds in the Intertidal Flats of Brazil

The tidal flats of the Bragantinian Peninsula in the tropical part of Brazil harbour wintering and migratory nearctic shorebirds in very high densities, whereas the benthic food supply is very low. In 2001 and 2002 a study was conducted on the habitat choice and distribution of shorebirds to investigate the formation of niches and the spatial distribution under the constraint of a limited food supply. We showed that shorebird densities were not correlated with a range of abiotic variables or with prey density within sites, but that between sites birds tended to select sites with peak prey densities. Two foraging guilds were differentiated: Whimbrel Numenius phaeopus, Willet Tringa semipalmata and Short-billed Dowitcher Limnodromus griseus preferred to forage in the water or on wet sand at the water's edge; while Red Knot Calidris canutus, Grey Plover Pluvialis squatarola, Ruddy Turnstone Arenaria interpres, Semipalmated Sandpiper Calidris pusilla and Semipalmated Plover Charadrius semipalmatus, were found predominantly on dry substrate. Although the birds showed species-specific preferences for characteristics defining microhabitats, niches were broadly overlapping. The results of our study suggest that, in case of a very low food supply, individuals might not be able to react to competition by niche segregation but might be forced to feed in a broad range of available niches.

O uso de praias arenosas com diferentes concentrações humanas por espécies de aves limícolas (Charadriidae e Scolopacidae) neárticas no sudeste do Brasil

As aves migratórias podem reconhecer humanos e animais domésticos como possíveis predadores, alterando seus padrões de abundância e comportamento de formação de bandos. O objetivo do presente estudo foi comparar a abundância de aves migratórias neárticas, a freqüência de bandos e o número médio de aves por bando em áreas com alta e baixa concentração humana em uma região costeira de praia arenosa no sudeste do Brasil. As aves, pessoas e cães foram contados mensalmente entre novembro de 2006 a abril de 2007. Foram registradas seis espécies de aves (Arenaria interpres, Calidris alba, Calidris canutus, Calidris pusilla, Charadrius semipalmatus, Pluvialis dominica) nas duas áreas, no entanto somente C. canutus foi registrado exclusivamente na área com baixa concentração humana. Houve diferença significativa no número médio de pessoas e cães entre as áreas, mas não no número médio de aves. Não houve correlação entre o número de humanos e aves, e entre cães e aves. Adicionalmente, não houve diferença significativa na freqüência de bandos e número de indivíduos por bando entre as áreas. Os resultados deste estudo destacaram a sensibilidade de C. canutus na área com alta concentração humana e a necessidade de futuras investigações que determinem os limites máximos de concentração de pessoas e cães domésticos que as aves migratórias neárticas podem tolerar para a tomada de ações de proteção em áreas costeiras com ocupação humana.

Variation in the innate and acquired arms of the immune system among five shorebird species

To contribute to an understanding of the evolutionary processes that shape variation in immune responses, we compared several components of the innate and acquired arms of the immune system in five related, but ecologically diverse, migratory shorebirds (ruff Philomachus pugnax L., ruddy turnstone Arenaria interpres L., bar-tailed godwit Limosa lapponica L., sanderling Calidris alba Pallas and red knot C. canutus L.). We used a hemolysis-hemagglutination assay in free-living shorebirds to assess two of the innate components (natural antibodies and complement-mediated lysis), and a modified quantitative enzyme-linked immunosorbent assay in birds held in captivity to assess the acquired component (humoral antibodies against tetanus and diphtheria toxoid) of immunity. Ruddy turnstones showed the highest levels of both innate and acquired immune responses. We suggest that turnstones could have evolved strong immune responses because they scavenge among rotting organic material on the seashore, where they might be exposed to a particularly broad range of pathogens. Although ruffs stand out among shorebirds in having a high prevalence of avian malaria, they do not exhibit higher immune response levels. Our results indicate that relationships between immune response and infection are not likely to follow a broad general pattern, but instead depend on type of parasite exposure, among other factors.

Increased nest predation in a declining and threatened Temminck's Stint Calidris temminckii population

We measured nesting success of the Temminck's Stint Calidris temminckii along the Finnish Bothnian Bay coast during 19 breeding seasons (1983–2001) and conducted a population census (1999–2002). We found 105 pairs, showing a marked decline from the previous survey (170 pairs 1987–95). Of the 424 ‘known‐fate’ nests, 47% hatched. Depredation caused 79.9% of the nest losses. Nesting failures increased from 1983–91 to 1992–2001 owing to a rise in nest predation. The proportion of failed nests that failed because of predation rose from 48.9 to 87.7%. When only depredated nests were considered as losses, Mayfield nest survival probability over the incubation period dropped from 69 to 31% (461 nests). This pattern emerged both in man‐made and in natural habitats. Survival probability was independent of habitat type (natural vs. man‐made). In an experiment involving videotaping of dummy nests, Common Gull Larus canus and Ruddy Turnstone Arenaria interpres were found to be the most important egg predators.

Predicting the effects of marine climate change on the invertebrate prey of the birds of rocky shores

By the end of the 21st century models of climate change predict that the air temperature over most of the British Isles will increase by between 2 and 3 °C and sea‐level will rise by 40–50 cm. Over that period it will become windier and mean wave height will increase, as will the frequency of storms. These changes in climate and weather will impact the intertidal zone of the UK and will cause distribution changes in many of the common invertebrate species that live there. Where these changes are severe they may well impact on patterns of distribution of ducks and wading birds. In the British Isles a number of organisms live close to their geographical limits of distribution. Some of these species might be expected to extend their range as climatic restraints are relaxed. Species currently limited by cool summers or winter cold will move northwards. In most cases the effects on the distribution of waterbirds will be small. For example, the replacement of the Northern Limpet Patella vulgata by the Southern Limpet P. depressa is unlikely to adversely affect Eurasian Oystercatchers Haematopus ostralegus. Of wider concern is the possibility that as climate warms the abundance and productivity of brown algae will decrease. This is likely to have two significant effects for waders. First, it would represent a loss of potentially rich feeding grounds for species such as Ruddy Turnstone Arenaria interpres that feed on small easily desiccated invertebrates living on or below the seaweed. Secondly, as algae die or are broken away the resulting debris is exported to sediment habitats where it considerably boosts the in situ production of bacteria at the base of the food web. An increase in sea‐level will only have a major impact on the extent of rocky shore invertebrate communities where shore topography prevents the upward migration of the biota. Where a seawall limits shores, for example, biological production will be curtailed as the area available for colonization decreases. Increases in the size of waves and the frequency of storms will mimic increasing exposure and there will be a significant reduction in algal production in areas that are affected.

The possible impact of climate change on the future distributions and numbers of waders on Britain's non‐estuarine coast

The relationship between weather and wader distributions on non‐estuarine coasts is described and used to predict how future wader distributions may respond to climate change. The distributions of eight out of nine species of wader commonly wintering on the non‐estuarine coasts of Britain altered between two similar surveys, in 1984/85 and 1997/98, that covered 78% and 38% of Britain's 12 594 km of non‐estuarine coastline, respectively. These eight species moved at least in part either eastwards along the winter isotherms or northwards. These changes in distribution broadly coincide with a distributional shift towards the species’ respective breeding grounds and are correlated with the local winter weather over the period: increasingly mild extreme temperatures and changes in mean rainfall, mean wind speed and wind‐chill. Based on the scenarios for Britain's climate in 2020 and 2080, it is predicted that the distributions of the waders will move away from the west. The non‐estuarine coasts of Britain hold particularly high proportions of the international flyway populations of Ringed Plover Charadrius hiaticula, Sanderling Calidris alba, Purple Sandpiper Calidris maritima and Ruddy Turnstone Arenaria interpres that are all expected to show continuing decline to 2080. Overwintering waders appear to be good indicators of the effects of climate change.

Environmental heterogeneity, spatial segregation of prey, and the utilization of southwest Atlantic mudflats by migratory shorebirds

We studied the relationships between the habitat use of migratory shorebirds and the spatial distributions of the Southwestern Atlantic Fiddler Crab Uca uruguayensis, polychaetes, sediment characteristics and tidal levels in the Río de La Plata estuary, Argentina, where U. uruguayensis is one of the most important intertidal species. Crabs have a well‐defined patchy distribution that is segregated spatially from that of polychaetes. Crab density on the surface varied across the tidal cycle, reaching maximum values during low tide. Polychaete density decreased with depth but showed no change through the tidal cycle; however, given that sediment penetrability did change during the same period, their availability to probing shorebirds is expected to change. Habitat use by shorebirds followed the spatial distribution of prey; shorebirds that foraged on polychaetes (White‐rumped Sandpiper Calidris fuscicollis, Two‐banded Plover Charadrius falklandicus and Hudsonian Godwit Limosa haemastica) focused their attention on the areas with the highest densities of polychaetes, whereas species that preyed mostly on crabs (Ruddy Turnstone Arenaria interpres, Whimbrel Numenius phaeopus and Grey Plover Pluvialis squatarola) predominantly used areas with crabs. This segregation occurred particularly during low tide, a period in which polychaetes became fully available. Results show that the spatial and temporal heterogeneity of mudflats in relation to the types and availability of prey has a strong effect on shorebird habitat use.