Tringa Glareola Research Articles

Avifaunal inventory of Laysan Island, Hawaii, USA

Here I present a 6-month bird inventory of Laysan (25.776° N, 171.733° W), a coral island in the Northwestern Hawaiian Islands. Forty-four species belonging to 17 families were recorded, including six globally threatened species. Three species new to Laysan were found: Tringa brevipes, Tringa glareola, and Larus hyperboreus. This study expands upon previous ornithological coverage of the island, the majority of which has been partial, transitory, or historical.

Age‐specific variation in relationship between moult and pre‐migratory fuelling in Wood SandpipersTringa glareolain southern Africa

Trans‐equatorial avian migrants tend to breed, moult and migrate – the main energy‐requiring events in their lifecycle – at different times. Little is known about the relationship between wing moult and pre‐migratory fuelling in waders on their non‐breeding grounds, where time is less constrained than during their brief high‐latitude breeding season. We determined age‐related strategies of Wood SandpipersTringa glareolato balance the energetic demands of primary moult against pre‐migratory fuelling in southern Africa by analysing body mass and primary moult at first capture of 1721 birds mist‐netted in 1972–96 at waterbodies in Zimbabwe. Adults moulted all their primaries in August–December, but immatures underwent a supplemental moult of varying numbers of outer primaries in December–April, close to departure. We used locally weighted linear regression to estimate trends in Wood Sandpiper body mass from 1 July to 1 May. They maintained low mass from arrival in July–September to February–early March. Adults fuelled from 10 February to 1 May at a mean rate of 0.25 g/day (sd = 0.16). Most adults (98%) began fuelling 10–75 days after completing primary moult. Immatures fuelled from 4 March to 13 April at 0.24 g/day (sd = 0.14). They used varying strategies depending on their condition: a brief gap between moult and fuelling; an overlap of these processes near departure, leading to slower fuelling; or skipping fuelling altogether and staying in southern Africa for a ‘gap year’. Immatures moulting three or five outer primaries fuelled more slowly than post‐moult birds. Immatures moulting four outer primaries started fuelling 3 weeks later but at a higher rate than did post‐moult birds of this group. In post‐moult immatures, the later they ended moult, the later and faster they fuelled. The heaviest adults and immatures using all moult patterns accumulated fuel loads ofc. 50% of lean body mass, and could potentially cross 2397–4490 km to reach the Great Rift Valley in one non‐stop flight. Immatures were more flexible in the timing and extent of moult and in the timing and rate of fuelling than adults. This flexibility enables inexperienced Wood Sandpipers to cope with inter‐annual differences in feeding conditions at Africa's ephemeral inland waterbodies.

Changes in the breeding bird communities on mires and in surrounding forests in southeastern Norway during a 40-year period (1976–2015)

The breeding bird communities of 18 mires and surrounding forests in southeastern Norway were censused in 1976–77 and in 2015. We found that 53% of the mire species with sufficient data for analyses showed significant changes. Red-throated Diver Gavia stellata, Common Crane Grus grus, Wood Sandpiper Tringa glareola and Tree Pipit Anthus trivialis increased, whereas Northern Lapwing Vanellus vanellus, Black-headed Gull Chroicocephalus ridibundus, Meadow Pipit Anthus pratensis and Yellow Wagtail Motacilla flava decreased. There were also near significant decreases of Eurasian Curlew Numenius arquata and Eurasian Skylark Alauda arvensis. Population changes did not differ between short- and long-distance migrants. Species with marginal populations on mires declined more than mire specialist species, suggesting an indirect negative influence of problems in other habitats. Overall, there was a significant 19% decline in number of mire species, but a non-significant 7% increase in number of individuals. The bird community in the forests surrounding the mires showed significant population changes for 42% of the species with sufficient data for analyses, with increases in many resident forest species, but less so for migrants. Overall, there was a near significant 12% increase in number of forest species, and a significant 28% increase in number of individuals. Mire- and forest-associated species did not differ in population trends. Among short-distance migrants (mire and forest species combined), species wintering in agricultural habitats had more negative population changes than species wintering in other habitats. Thus, the breeding bird community on and around mires in this part of Norway has undergone large changes during the last 40 years. We discuss our results in relation to general trends of bird communities in northern Europe.

Minor differentiation of foraging niche may have a major impact on the incidence of avian botulism in shorebirds

Avian botulism is a fatal disease of birds caused by ingestion of neurotoxins produced by Clostridium botulinum type C and is now recognized as the most common cause of death in waterbirds worldwide. Although tens of species have been reported to suffer from avian botulism, it remains unknown which ecological factors primarily determine inter-specific variation in the incidence of this disease. We hypothesized that an exposure of birds to botulin may largely depend on their foraging niche, as the toxin is available mostly at the sediment surface, especially during the carcass-maggot stage of botulism epizootics. To test this hypothesis we used capture-recapture methods to estimate mortality of two shorebird species differing in bill morphology and foraging niche, wood sandpiper Tringa glareola (short bill, surface-feeding) and common snipe Gallinago gallinago (long bill, deep probing), during a major avian type C botulism outbreak in central Poland. All the reported cases of shorebird mortality were attributed to botulism and we found large differences in daily survival rates of both species (0.87 and 0.99 in wood sandpipers and common snipe, respectively). Even assuming much shorter stopover duration of wood sandpipers, survival rate over the entire stopover period was estimated at 0.57 in the wood sandpiper and at 0.90 in the common snipe. To our knowledge, this is the first non-circumstantial evidence that relatively minor differentiation of foraging niche may have a major impact on the incidence of avian botulism in birds. Our data might also suggest that, on the evolutionary time scale, avian type C botulism may constitute a strong selective pressure acting on foraging niches of shorebirds, and possibly other waterbirds.

Large-Scale Monitoring of Waders on Their Boreal and Arctic Breeding Grounds in Northern Europe

Large-scale and population-wide monitoring of waders on their boreal and arctic breeding grounds has hitherto been lacking, mainly because logistics are truly challenging in regions with few ornithologists, vast areas and few roads. In Norway, Sweden and Finland (here ‘Fennoscandia’) there are now national monitoring schemes in place, aimed at tracking all bird species, which allows trends to be estimated for northern wader populations. We present joint Fennoscandian population trends for 24 wader species, covering the period 2002–2013 (in some cases somewhat shorter time periods). The data stem from 1263 routes in Norway, Finland, and the northern two thirds of Sweden, all situated north of 58°N. This area of one million km2 largely coincides with the boreal and arctic parts of Fennoscandia. The trends found are rather evenly distributed between strong increases and strong declines. Trends do not differ between short- and long-distance migrants, nor do they vary in relation to breeding latitude. Ringed Plover Charadrius hiaticula, Wood Sandpiper Tringa glareola, Green Sandpiper T. ochropus and Common Redshank T. totanus had significant positive trends, whereas Common Snipe Gallinago gallinago, Ruff Philomachus pugnax and Spotted Redshank Tringa erythropus were declining significantly in numbers. Trends could be calculated even for relatively uncommon breeding birds such as Temminck's Stint Calidris temminckii, Eurasian Dotterel Charadrius morinellus, Broad-billed Sandpiper Limicola falcinellus, Jack Snipe Lymnocryptes minimus and Red-necked Phalarope Phalaropus lobatus, although these trends build on few routes and individuals, and thus have low precision. The monitoring schemes in Norway and Finland are expected to increase in coverage in the coming years, with up to a total of 1555 northern routes being tracked when the schemes are fully developed. This should enable still more robust trend estimates for northern waders on their Fennoscandian breeding grounds to be calculated in the future.

Human disturbance of breeding Wood Sandpipers Tringa glareola: implications for "alert distances" in prescribing protective buffer zones

Separation of animals and humans using a protective set-back distance (Minimum Ap-proaching Distance) is a popular tool for conservation managers to promote wildlife-hu-man coexistence. In several cases, Minimum Approaching Distance is based on how ani-mals respond to an approaching human, using Flight Initiation Distance or Alert Distance. Alert Distance, when animals first show increased vigilance to an approaching human, is considered the best basis for Minimum Approaching Distance because animals have time to adapt their response. Alert Distance is frequently difficult or impossible to measure in practice, however, especially in breeding birds. Using a study of breeding Wood Sandpip-ers Tringa glareola, in which Alert Distance could not be measured directly, we tested three possible solutions to this dilemma. Alarm Call Distance did not appear to provide a useful substitute for Alert Distance because sandpipers probably alarm called after they had first detected a human. Published predictions of Alert Distance using body mass also failed to provide realistic estimates of disturbance distances in Wood Sandpipers. The "fixed-slope rule", which predicts that Alert Distance is about double Flight Initiation Distance, was not supported by relationships between Alarm Call Distance and Flight Ini-tiation Distance, but was supported by a relationship between an estimated Alert Distance surrogate and Flight Initiation Distance. This suggests that this rule may have general util-ity in predicting Alert Distance when only the more readily measured Flight Initiation Distance metric is known. A Minimum Approaching Distance (protective buffer zone) of 160 m is recommended for breeding Wood Sandpipers.

Does intraspecific competition facilitate age separation in timing of southward migration in waders?

In many Palaearctic wader species there is a clear separation in the timing of adult and juvenile southward migration. This phenomenon is traditionally explained by the selection on adults to depart early from breeding grounds and necessity of juveniles to prepare longer for migration. In this study we hypothesize that late departure from natal grounds may also be adaptive for juveniles, as it allows them to avoid intensified interference competition at stopover sites with adult, usually more dominant conspecifics. To test this hypothesis we analysed long-term data on stopover behaviour of juvenile wood sandpipers (Tringa glareola) staying at a central Polish stopover site under varying levels of competition from adult birds. The results clearly indicated that juveniles were highly disadvantaged by the simultaneous presence of adults at the same staging site, as under intense competition from older conspecifics they refuelled more slowly and attained lower fat reserves. It was also found that juveniles which were forced to compete with adults left the site quickly and possibly searched for more favourable staging places. All these imply that delayed departure from natal grounds may be adaptive for juvenile waders, allowing them to mismatch the timing of their first migration with the peak of adult passage and, thus, reduce the negative consequences of intraspecific competition during migration.

Population trends and migration strategy of the Wood Sandpiper Tringa glareola at Ottenby, SE Sweden

Long-term ringing data are useful for understanding population trends and migration strategies adopted by migratory bird species during migration. To investigate the patterns in demography, phenology of migration and stopover behaviour in Wood Sandpipers Tringa glareola trapped on autumn migration at Ottenby, southeast Sweden, in 1947 − 2011, we analysed 65 years of autumn ringing data to describe age-specific trends in annual trappings, morphometrics and phenology, as well as fuel deposition rates and stopover duration from recapture data. We also analysed the migratory direction of the species from recovery data. Over the years, trapping of both adults and juveniles has declined significantly. Median trapping dates were 10 July for adults and 6 August for juveniles. Average migration speed of juvenile birds was 58.1 km d−1. Adults stayed on average 3.5 days and juveniles 5.2 days, with average fuel deposition rates of 2.5 and 0.7 g day−1 respectively. Juvenile birds probably vary their strategy according to time of season and prevailing conditions. Both adults and juveniles followed the Mediterranean Flyway, but juveniles displayed significantly more southerly and significantly more scattered migratory directions.

Population‐wide body mass increment at stopover sites is an unreliable indicator of refuelling rates in migrating waders

Estimates of refuelling rates in migrating waders are best based on intra‐seasonal recaptures of individually marked birds. This method, however, has methodological problems associated with capture effects and difficulties in attaining sufficient sample sizes. An alternative method had been proposed whereby refuelling rates are approximated by the body mass increment from the slope of the regression between body masses of all birds caught at a site and date. We investigated the appropriateness of this indicator with a simulation study in non‐synchronized migratory species (i.e. arrivals and departures of individuals at the stopover site are not synchronized). Simulation results indicated that the mass increment across the population may be used as an approximation of refuelling rate only in populations with low turnover rates (percentage of birds arriving at/departing from stopover site per day <2%) and ideally with constant numbers of staging birds. The mass increment of non‐synchronized populations with moderate or high turnover rates (higher than 5%) depends mainly on body masses of arriving birds and is not indicative of the individual rate of refuelling. The results of the simulation study were confirmed with empirical data gathered from Wood Sandpiper Tringa glareola and Common Snipe Gallinago gallinago during their autumn migration at a stopover site in Poland. The population mass increment methods considerably underestimated refuelling rate obtained from the recapture‐based approach of individual birds in both species. As a consequence, we suggest that population mass increment should not be used as an indicator of refuelling rates in non‐synchronized stopover populations of migrating waders.

Description Of Avian Bio-Diversity Of Damdamma Jheel In Gurgaon District In Haryana, India

Damdamma Jheel is a wetland of impressive potentials of harboring rich avian bio-diversity in the accompaniment of enhanced habitat reconstruction and improvement. It is located in the National Capital Region, nearby Sohana town in Gurgaon district in Haryana merely 45 Kms from Dhaula Kuan in New Delhi. At present, compared to Sultanpur National Park, it is confronting neglect. Considering its positive features of terrain, water sheet, it has the qualities of being a rich habitat for birds of all hues including the winter migratory birds. The present studies focus attention on its avian biodiversity as well as its own degraded form and structure. In all, 128 species of birds belonging to 15 orders and 41 families could be enlisted. Order Passeriformes is the predominant one having 54 species, followed by Charadriiformes (14 Species) and Ciconiiformes (12 Species). The prominent winter migratory birds observed from Damdamma Jheel include Asian Openbill Stork Anastomus oscitans , Eurasian Spoonbill Platalea leucorodia , Northern Shoveller Anas clypeata , Northern Pintail Anas acuta , Common Teal Anas crecca , Common Pochard Aythya ferina , Gadwall Anas strepera , Spot-billed Duck Anas poecilorhyncha , Spotted Redshank Tringa erythropus , Common Redshank Tringa tetanus, Common Greenshank Tringa nebularia , Kentish Plover Charadrius alexandrinus , White-tailed Lapwing Vanellus leucurus , Marsh Sandpiper Tringa stagnatilis , Wood Sandpiper Tringa glareola , Common Sandpiper Actitis hypoleucos , White Wagtail Motacilla alba and Yellow Wagtail Motacilla flava . The lake is suffering from water scarcity considering its capacity and potential to have more water. The periphery towards east is plagued by the growth of peats. The very fact that in October 2012, a large group of Openbill Stork (Nearly 70-80) has already arrived at Damdamma Lake since September-2012 indicates that it is the largest HARBOUR of Open-bill Stork in Haryana. Also, Eurasian Spoonbills were seen in a group 10-12, again the largest in Haryana. It is argued in this paper, that Damdamma is the pride lake of Haryana and prime harbor for uncommon winter migratory birds like Open-bill Stork and Eurasian Spoonbill must be the prime place for habitat reconstruction by Ministry of Environment and Forest, Govt. of India in conjunction with Govt. of Haryana with the active contributions by WWF (India) to add to the might vastness of this lake an element of grace and glory so as to conserve the winter migratory birds during their sojourn in India. In addition, it will be one nodal point to include Sultanpur National Park, Badkhal Lake, Bhindawas and Keoladeo National Park as an eco-tourism rectangle with provision for night halt.

TRADITIONAL RURAL WETLANDS IN HARYANA STATE OF INDIA ARE CURRENTLY CONFRONTING MULTICORNERED THREATS LEADING TO EXTINCTION SOONER THAN LATER

The most serious threat to traditional rural ponds in Haryana is associated with transformed societal behavioural patterns, ethics, values and life style, amongst several others. The siltation of ponds with adjoining areas, soil coming in with rain water is a very serious cause of stratification of rural ponds. Also contracting of village community land for sun drying of cow dung cakes inspires villagers to overload periphery of each pond with cow dung turning the premises into grave-yard of dung. This dung is the major source of polluting pond water into blackish water with high load of organic matter. Moreover, it leads to over excessive eutrophication. Building of major highways and connectivity roads have resulted into compartmentalization and degradation of village ponds. Inhabitation of peripheral village ponds boundaries by lower section of society for dwelling purposes is more threat to wetlands. The indifferent inclination of villagers towards silted ponds drenched in bad odour and blackish sludge is the story of 80% of the cases. The total blockage of run-off rainy water towards the natural age old rural ponds due to obstruction by way of human inhabitation has resulted into desertification of shallow water sheet in 90% of the cases. The oblivion of harvesting dried silt in summer for brick making has spelled doom for the ponds turning them into flat ground through successive decades and so on. The water quality in all ponds was overshooting the decaying stage due to the continuous mixing of cow dung drenched rainy water. Over excessive usage of ponds for bathing of cattle, dumping of cow dung and rotten vegetables waste has turned ponds into live sinks of dirt, garbage and rural dairy wastes. Majority of village ponds are now out of existence or in deep black sludge laden or converted into Fish-Farming wetlands. The present studies have indicated that Winter migratory birds like Greylag Goose Anser anser, Bar-headed Goose Anser indicus, Mallard Anas platyrhynchos, Gadwall Anas strepera, Northern Shoveller Anas clypeata, Northern Pintail Anas acuta, Garganey Anas querquedula, Common Teal Anas crecca, Common Pochard Aythya ferina, Tufted Pochard Aythya fuligula, Common Coot Fulica atra, Little Ringed Plover Charadrius dubius, Kentish Plover Charadrius alexandrines, Spotted Redshank Tringa erythropus, Common Redshank Tringa tetanus, Marsh Sandpiper Tringa stagnatilis, Wood Sandpiper Tringa glareola and Pied Avocet Recurivirostra avosetta arrive in the extremely dilapidated rural ponds in Haryana from far off places including Russia, Siberia, China, and Caspian region, east Asia each winter season without any break. As such the extinction of ponds in Haryana directly threatens global avian biodiversity. Keywords: Traditional Rural Wetlands, Perennial Rainy Water, Road Side Puddles, Land Filling, Commercial and Residential Construction, Highway reconstruction

Sex and age differences in the development of breeding plumage in the Wood Sandpiper Tringa glareola during spring migration in north-eastern Poland

We investigated the effects of sex and age on the progression of breeding plumage moult in the Wood Sandpiper, a migrant wader that shows weak sexual size dimorphism and no dichromatism. We sexed the birds by DNA and examined the plumage of 416 Wood Sandpipers caught at a spring stopover site in north-eastern Poland. We scored the proportion of new breeding-type feathers on the head, back and scapulars in 20%-wide stages, and summed these scores as a body moult index, and on the lesser and median wing coverts summed as a wing covert moult index. Only 10% of all these birds fully developed breeding plumage on the upper body and 8% had only 21-40% of new feathers there. About 90% of the birds had moulted less than half of their wing coverts. No Wood Sandpiper showed a complete breeding plumage. We investigated whether moult indices were related to the date of the bird's capture and its body mass adjusted for size, age and sex, using generalised linear models. The best model indicated that the body-moult index was significantly affected by age, sex and year. Immatures had a more advanced body moult than adults, and females were more advanced than males. None of the predictors had a significant effect on the wing-covert moult index.

Variation in Autumn Migration Strategy in the First-Year Wood SandpipersTringa glareola

Abstract. Wood Sandpipers are generally known to follow a time-minimization migration strategy on their autumn passage. We investigated whether the migration strategy adopted by first-year Wood Sandpipers is susceptible to temporal variations. Wood Sandpipers were trapped during the July–September period from 1997 to 2007 at the Jeziorsko reservoir, central Poland. Intra- and inter-seasonal variation in stopover length, refuelling rates, departure fat loads and flight range were investigated. There was a constant decline in the refuelling rates over the course of the migratory season, reaching 0.55 g/day at the end of August. Such low refuelling rates are considered typical of energy-minimizers. Despite showing high refuelling rates at the beginning of the season, first-year Wood Sandpipers left the stopover site with relatively low fuel reserves, resulting in a low potential flight range of about 1200 km, which suggested travelling in small hops — a trait characteristic of energy-minimizers. There was al...

Rapid or slow moult? The choice of a primary moult strategy by immature Wood Sandpipers Tringa glareola in southern Africa

Immature migrant waders have more complex patterns of primary moult than adults, but these have been described only fragmentarily. The Wood Sandpiper Tringa glareola breeds in the taiga region of the Palearctic and part of the population migrates to southern Africa. We selected this population for a study of the primary moult strategies of an immature wader. After analysing the moult formulae of 674 immatures, we discuss potential factors that influence the choice of moult strategy. All moulters replaced two to six outer primaries; 91% moulted four or five. We used the Underhill–Zucchini model to estimate the timing and duration of moult in immatures replacing different numbers of primaries. A slow moult of five or six primaries, adopted by 29%, lasted on average 98–111 days, beginning on average 8–16 December. Moult of four primaries (63%) began on 6 January and averaged 73 days. A rapid moult of three primaries (7%) began on 24 January and averaged 55 days. All groups ended their moult between 19 and 28 March. GLM models showed that heavier immatures were more likely to start moulting than leaner birds. This tendency was more pronounced in November–January than in later months. The later the moult started, the fewer feathers were replaced and the faster the process. Departure time set the limit for the end of moult. We suggest the ability to choose different strategies allows immature Wood Sandpipers to adjust their moult to the variable conditions they encounter at wetlands in southern Africa.

Extended Primary Moult as an Adaptation of Adult Wood SandpipersTringa glareolato Their Freshwater Habitats in Southern Africa

Migrant waders using freshwater habitats are hypothesized to have slower primary moult than waders using coastal habitats. We chose the Wood Sandpiper Tringa glareola as a representative species using the freshwater habitats and compare its moult pattern with a range of fresh-water and coastal wader species to test the habitat hypothesis. Only fragmentary descriptions of Wood Sandpipers' primary moult in their sub-Saharan non-breeding quarters had existed. We analysed the primary moult formulae of 1496 adult Wood Sandpipers obtained in southern Africa. The Underhill & Zucchini moult model was used to estimate the timing and duration of moult for all 10 primaries combined and for each primary individually. We also estimated the rate of production of feather material during moult. Adult Wood Sandpipers arrive in southern Africa between late July and November, and depart from mid-March to April. Suspension of moult was observed in 56 birds (7.5%) after two to nine primaries had been replaced. The remaining birds performed a continuous complete primary moult, with average start and completion dates of 21 August and 30 December, respectively; estimated duration was 131 days. The overall rate of production of primary feather material was uniform, achieved by growing up to five small inner primaries simultaneously at the beginning of the moult but only one or two simultaneously while the large outer primaries were growing. Primary moult of adult Wood Sandpipers took longer but ended earlier than in similar-sized waders using coastal habitats. Compared with waders using coastal habitats, Wood Sandpipers prolonged moult by shedding their primaries at longer intervals and by extending the growth period of each primary. The longer primary moult and its earlier ending compared with coastal waders are probably adaptations to Wood Sandpipers' use of freshwater habitats, which in southern Africa provide unpredictable food supplies and might require nomadic movements between ephemeral inland wetlands.

A classification scheme for scoring subcutaneous fat depots of shorebirds

Different scoring systems have been developed for assessing fat stores in birds. Most have been used with passerines, and there is no widely used standard for studies of shorebirds. I developed a new fat-scoring classification scheme for shorebirds that was tested in Poland with juvenile Dunlins {Calidris alpina) during autumn and Wood Sandpipers ( Tringa glareola) during spring migration. My proposed fatness scale is based on a qualitative assessment of the amount of fat in the axillary region and, if necessary, the furcular region. The resulting fat scores do not predict the actual amount of fat carried by a bird, but can be used to assign birds to a particular state of fatness and allow comparison of birds with different scores. Analysis revealed that the relationship between fat scores and predicted fat mass was approximately linear for both Dunlins and Wood Sandpipers. Although the scale I propose was tested with 20 species of shorebirds, sample sizes for larger species were small and consisted exclusively of lean and moderately fat birds. As a result, my proposed fat-scoring system should be evaluated using larger and fatter shorebirds because it has only been validated for one small and one medium-sized species.

Differences in foraging ecology of Wood Sandpiper Tringa glareola and Ruff Philomachus pugnax during spring migration in Sajna River valley (nor thern Poland)

The research was conducted in 2002, in Sajna River valley (NE Poland). It was aimed at foraging ecology of two wader species not specialised in terms of feeding techniques. We found that while foraging on a stopover site during spring migration Ruffs used different ecological niche than Wood Sandpipers. Ruffs foraged significantly more often in medium and deep water and made also more medium and deep probes, what indicates preference in random probing. High intensity and proportionally low efficiency of foraging may confirm it. Contrary, Wood Sandpiper foraged less intensively but much more effectively; this, together with frequent changes of feeding places in terms of water level indicate that Wood Sandpiper to greater extent uses visual detection of prey than Ruff.

Autumn Passage of Waders (Charadrii) in the Middle Vistula Valley (Kaliszany, Central Poland)

Autumn Passage of Waders (Charadrii) in the Middle Vistula Valley (Kaliszany, Central Poland) The phenology and dynamics of wader migration were studied at a stopover area in the middle Vistula Valley (Kaliszany ringing station, 51°05'N, 21°48'E, central Poland). The study was conducted during autumn passage seasons of 1993-1996 and 1999-2001. At this time 364 counts were done from mid-July to the end of October. Altogether 23 030 waders of 27 species were recorded within the study period. The most numerous species observed were: the Northern Lapwing (Vanellus vanellus) — 49% of all birds, Common Sandpiper (Actitis hypoleucos) — 16% and Greenshank (Tringa nebularia) — 9%. Species constituting ca 2-4% of all noted waders each were: the Dunlin (Calidris alpina), Spotted Redshank (T. erythropus), Wood Sandpiper (T. glareola), Curlew (Numenius arquata), Ruff (Philomachus pugnax) and Green Sandpiper (T. ochropus). The proportion of the remaining species did not exceed 2%. The pattern of autumn migration dynamics is presented for the dominant species.

Spring migration dynamics and sex-specific patterns in stopover strategy in the Wood Sandpiper Tringa glareola

Due to being a virtually monomorphic wader species, migration dynamics and sex-related migration patterns in the Wood Sandpiper (Tringa glareola) have rarely been investigated. We captured spring migrants at an important stopover site in northeastern Austria. Birds were individually color-marked, and sex was determined by an analysis of DNA from tail feather material. Among temporary residents (birds seen again after day of capture), males migrated on average 3 days earlier than females. However, since sexes did not differ in fat score, the length of stay and the proportion of transients (birds not seen again after day of capture) and temporary residents, we suggest that males and females adopt similar migration strategies in the spring. The large number of transients captured as well as shorter stopover durations in later temporary residents indicate that Wood Sandpipers minimize time at this stage of their northbound migration. Temporary residents earlier in the season exhibited lower fat stores than later ones. Nevertheless, since the fat stores of transients and temporary residents were similar even after the progress of the season had been accounted for, we assume that Wood Sandpipers may afford to exhibit individual flexibility in migration strategy and the use of stopover sites, especially early in the season. This variability may be a necessary adaptation to cope with possible varying environmental conditions at dynamic and unpredictable inland stopover sites. After having reached North Mediterranean regions, mean body mass of spring migrants gradually increases during successive stopovers, indicating that Wood Sandpipers follow a ‘hopping’ migration strategy. This emphasizes the high conservation value of even small artificial mudflat pools as important stepping stones in order to maintain a continuous network of wetland habitats for this continental migrant.

Advances in Spring but Variable Autumnal Trends in Timing of Inland Wader Migration

Advancement of spring migration in response to recent global climate change is well documented for a variety of bird species, but the pattern for autumn migration is rather equivocal. During a 42-year period (1964–2005) the changes in timing of spring and autumn migration of eight wader species were studied at multiple inland sites in Central Europe (Czech Republic and Slovakia) using ringing data. While a clear pattern was found for the advancement of the spring passage, there were variable trends in the timing of the autumn passage. Three species significantly advanced (Wood Sandpiper, Common Sandpiper and Dunlin), three species delayed (Ruff, Snipe and Little Ringed Plover), and two species did not change the timing of the autumn passage (Little Stint and Green Sandpiper). Earlier studies had predicted that long-distance migrants wintering south of the Sahara would advance the timing of autumn migration, while short-distance migrants would postpone it. However, our findings do not fully conform to these predictions. Across species, the timing of both the spring and autumn passages was negatively associated with the winter North Atlantic Oscillation (NAO) index, suggesting that even in long-distance migrants the timing of migration might be under direct environmental control. In conclusion, phenological responses of birds to recent changes in climate are quite coherent for the early phenological phases; however, the responses to later phases are not so straightforward, and the present study contributes to this diverse pattern.