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SummaryThe extent of intertidal flats in the Yellow Sea region has declined significantly in the past few decades, resulting in severe population declines in several waterbird species. The Yellow Sea region holds the primary stopover sites for many shorebirds during their migration to and from northern breeding grounds. However, the functional roles of these sites in shorebirds’ stopover ecology remain poorly understood. Through field surveys between July and November 2015, we investigated the stopover and moult schedules of migratory shorebirds along the southern Jiangsu coast, eastern China during their southbound migration, with a focus on the ‘Critically Endangered’ Spoon-billed Sandpiper Calidris pygmaea and ‘Endangered’ Nordmann’s Greenshank Tringa guttifer. Long-term count data indicate that both species regularly occur in globally important number in southern Jiangsu coast, constituting 16.67–49.34% and 64.0–80.67% of their global population estimates respectively, and it is highly likely that most adults undergo their primary moult during this southbound migration stopover. Our results show that Spoon-billed Sandpiper and Nordmann’s Greenshank staged for an extended period of time (66 and 84 days, respectively) to complete their primary moult. On average, Spoon-billed Sandpipers and Nordmann’s Greenshanks started moulting primary feathers on 8 August ± 4.52 and 27 July ± 1.56 days respectively, and their moult durations were 72.58 ± 9.08 and 65.09 ± 2.40 days. In addition, some individuals of several other shorebird species including the ‘Endangered’ Great Knot Calidris tenuirostris, ‘Near Threatened’ Bar-tailed Godwit Limosa lapponica, ‘Near Threatened’ Eurasian Curlew Numenius arquata and Greater Sand Plover Charadrius leschenaultii also underwent primary moult. Our work highlights the importance of the southern Jiangsu region as the primary moulting ground for these species, reinforcing that conservation of shorebird habitat including both intertidal flats and supratidal roosting sites in this region is critical to safeguard the future of some highly threatened shorebird species.

In seasonal environments subject to climate change, organisms typically show phenological changes. As these changes are usually stronger in organisms at lower trophic levels than those at higher trophic levels, mismatches between consumers and their prey may occur during the consumers’ reproduction period. While in some species a trophic mismatch induces reductions in offspring growth, this is not always the case. This variation may be caused by the relative strength of the mismatch, or by mitigating factors like increased temperature-reducing energetic costs. We investigated the response of chick growth rate to arthropod abundance and temperature for six populations of ecologically similar shorebirds breedingin the Arctic and sub-Arctic (four subspecies of Red Knot Calidris canutus, Great Knot C. tenuirostris and Surfbird C. virgata). In general, chicks experienced growth benefits (measured as a condition index) when hatching before the seasonal peak in arthropod abundance, and growth reductions when hatching after the peak. The moment in the season at which growth reductions occurred varied between populations, likely depending on whether food was limiting growth before or after the peak. Higher temperatures led to faster growth on average, but could only compensate for increasing trophic mismatch for the population experiencing the coldest conditions. We did not find changes in the timing of peaks in arthropod availability across the study years, possibly because our series of observations was relatively short; timing of hatching displayed no change over the years either. Our results suggest that a trend in trophic mismatches may not yet be evident; however, we show Arctic-breeding shorebirds to be vulnerable to this phenomenon and vulnerability to depend on seasonal prey dynamics.

1. Satellite‐based technologies that track individual animal movements enable the mapping of their spatial and temporal patterns of occurrence. This is particularly useful in poorly studied or remote regions where there is a need for the rapid gathering of relevant ecological knowledge to inform management actions. One such region is East Asia, where many intertidal habitats are being degraded at unprecedented rates and shorebird populations relying on these habitats show rapid declines.2. We examine the utility of satellite tracking to accelerate the identification of coastal sites of conservation importance in the East Asian–Australasian Flyway. In 2015–2017, we used solar‐powered satellite transmitters to track the migration of 32 great knots (Calidris tenuirostris), an “Endangered” shorebird species widely distributed in the Flyway and fully dependent on intertidal habitats for foraging during the non‐breeding season. 3. From the great knot tracks, a total of 92 stopping sites along the Flyway were identified. Surprisingly, 63% of these sites were not known as important shorebird sites before our study; in fact, every one of the tracked individuals used sites that were previously unrecognized.4. Site knowledge from on‐ground studies in the Flyway is most complete for the Yellow Sea and generally lacking for Southeast Asia, Southern China and Eastern Russia.5. Synthesis and applications. Satellite tracking highlighted coastal habitats that are potentially important for shorebirds but lack ecological information and conservation recognition, such as those in Southern China and Southeast Asia. At the same time, the distributional data of tracked individuals can direct on‐ground surveys at the lesser known sites to collect information on bird numbers and habitat characteristics. To recognize and subsequently protect valuable coastal habitats, filling knowledge gaps by integrating bird tracking with ground‐based methods should be prioritized.

Protected areas (PAs) are a cornerstone of modern conservation. For PAs that are established to conserve mobile species, it is important to cover all the key areas regularly used by these species. However, zonation and boundaries of PAs have often been established with limited knowledge of animal movements, leaving the effectiveness of some PAs doubtful. We used radio tracking data to evaluate the extent to which two coastal PAs in mainland China encompassed the full range of habitats used by migratory shorebirds during non-breedingseasons. The core zone (highest restriction on human activities) of the Yalu Jiang Estuary National Nature Reserve (Liaoning) incorporated only 22 ± 6% (n=34) of the diurnal home range (95% kernel density) of the endangered great knots Calidris tenuirostris. In contrast, the core zone of Chongming Dongtan (Shanghai) incorporated 73 ± 24% (n=25) of the home range of dunlins Calidris alpine. During high tide, great knots in Yalu Jiang mostly occurred in the experimental zone (least restriction on human activities) or sometimes outside the PA boundary altogether, where the birds could face substantial threats. By investigating satellite tracking records, consulting published literature, interviewing local experts and mapping habitat composition in different coastal PAs in China, we found that wet artificial supratidal habitats were frequently used by migratory shorebirds but the coverage of these habitats in coastal PAs was low. These PA boundaries and/or zonations should be revised to conserve mobile species more effectively. With the increasing number of tracking studies, analysing the spatial relationships between PAs and the movement ranges of mobile species can increasingly inform the development of a representative, comprehensive PA network.

Bengawan Solo Estuary has a very large area of mudflat, which make it suitable area for waterbird’s habitat. The purpose of this study were to determine the value of diversity index of waterbirds. This study was conducted in mudflat area at Kali anyar estuary, Bengawan Solo. Data was collected on March 2018. The method used to calculate the waterbirds was concentration count and to estimate the population was used block method. The result showed that value of diversity index of birds was 2,029 with the value index of evenness was 0,553. Total species found were 39 species from 7 families. Calidris canutus, Calidris tenuirostris, Chlidonias hybridus and Chlidonias leucopterus were dominant species. There were 2 species Endagered and, 7 spesies Near Threatened according to IUCN also Tweleve spcies were protected in Indonesia. Keywords: Bengawan Solo, bird diversity, mudflat, waterbirds

The mitochondrial genome of Calidris tenuirostris and Limosa lapponica were described using the whole mitochondrial genome obtained from Illumina Next-Generation Sequencing (NGS) technology. Total length of the mitogenome of C. tenuirostris was 16,732bp with slight A+T bias (55.3%). Genome size of L. lapponica was 16,773bp long and A+T biased (56.3%). Both gemones consisting of 2 rRNAs, 13 protein-coding genes, 22 tRNA genes and 1 non-coding regions. This is the first report of complete mitogenomes of these two shorebird species, (C. tenuirostris and of L. lapponica). We observed paraphyletic relationship among the species in the Family Scolopacidae. Also our result showed analogous patterns with the previous studies on the parallel relationships of shorebird species. This study provides basic genetic information for help in understanding phylogenetic relationships . within the Charadriiformes.

Supplemental feeding to mitigate the effects of food shortages may in some cases provide critical help to species conservation . However, supplemental feeding may have both positive and negative effects on wildlife and the environment. A scientifically designed feeding project helps to achieve conservation targets and reduces adverse effects. Here, we summarize a three-step framework for food supplementation that we used in practice: (1) determining whether supplemental feeding is required; (2) designing and implementing a practical feeding scheme; and (3) evaluating the effectiveness of food supplementation. We supplemented food for great knots (Calidris tenuirostris), an endangered migratory shorebird , at a recently impoverished refuelling site (Yalu Jiang estuary) in the Yellow Sea in spring 2018. The abundance of the staple food of great knots (Potamocorbula laevis, which had become very rare after 2012), was insufficient for the birds to refuel before the migratory flight to the breeding grounds . In our practical test, living P. laevis were collected in subtidal areas and transported to the intertidal area where great knots had been foraging in earlier years. The supplemented areas attracted 48% of all the great knots present in the 200 km2 study area. Nearly 90% of the supplemented food was consumed. Most great knots (>80%) foraged inthe high-density supplementation zone where the densities of P. laevis were restored to the naturally occurring levels in 2011–2012. Here, food intake rates (mg AFDM/s) were 4.2 times those in the adjacent control zones. The framework and the feeding practice should help guide future supplemental feeding in a wide range of species.

SummaryThe natural coastal wetlands of the East Asian-Australasian Flyway (EAAF) are disappearing at alarming rates, leading to rapid declines of many populations of waterbirds in the most species-rich flyway in the world. The identification and assessment of possible alternative habitats that may buffer the loss of natural wetlands should, therefore, be a priority for the conservation of migratory waterbirds using this flyway. Coastal saltpans are functional wetlands that support large numbers of waterbirds worldwide. The Nanpu Saltpans in the northern Bohai Bay of the Yellow Sea in China are one of the largest (290 km2) saltpan complexes in the world. In this paper, we document the value of the Nanpu Saltpans for supporting waterbirds. The surveys, carried out from 2013 to 2016, included waterbird counts in the saltpans (93 km2) at high and low tide and on the adjacent natural tidal flats (57 km2) at low tide. Of the 89 waterbird species recorded, 27 had maximum counts exceeding the 1% threshold value of estimated flyway populations. The maximum counts of waterbirds in northward migration and southward migration in the Nanpu Saltpans were 96,000 and 93,500, respectively, including both foraging and roosting birds; these figures do not account for turnover, so the total number of birds using the site is likely to be higher. The maximum counts on the adjacent tidal flats at low tide amounted to 73,000 and 20,000 waterbirds during northward and southward migration, respectively, and most of them were foraging birds. In the boreal winter, few birds fed in the saltpans, but several thousand fed on the tidal flats. Waterbirds used the inland ponds (2.0–18.0 km from the intertidal area) mainly for feeding both during low tide and high tide and used the nearshore ponds (0.3–4.3 km from the intertidal area) mainly for high-tide roosting. Some species, such as Black-tailed Godwit Limosa limosa, Marsh Sandpiper Tringa stagnatilis, Pied Avocet Recurvirostra avosetta, and Black-winged Stilt Himantopus himantopus, occurred mainly in the saltpans; other species preferred tidal flats, such as Red Knot Calidris canutus, Great Knot Calidris tenuirostris, Bar-tailed Godwit Limosa lapponica, Eurasian Curlew Numenius arquata, Relict Gull Larus relictus, and Grey Plover Pluvialis squatarola. This study clearly demonstrates the joint ecological function of the Nanpu Saltpan complex and adjacent tidal flats as a key staging area for waterbirds in the EAAF, and as such both urgently warrant protected status.

Background The motivation of birds to proceed with migration is associated with both endogenous and exogenous factors. According to their migratory situation and to the characteristics of stopover sites, birds might exhibit migratory motivation differently among sites. Although migratory motivation of migrating birds has been well studied in many species, the investigation of the same species in different migratory situations and at different stopover sites is still limited. We predicted that birds at different stopover sites could differ in migratory disposition, including expression of migratory restlessness and responses to environmental cues. Methods Here we compared migration motivation and orientation of Great Knots (Calidris tenuirostris) at two stopover sites, Chongming Dongtan in the south Yellow Sea, which is a temporary rest site, and Yalujiang Estuary Wetland in the north Yellow Sea, which is a critical refuelling site, during northward migration. Modified Emlen funnels, with thermal paper inside to record scratches of the birds, were used to detect activity (intensity and direction) of birds. Environmental conditions, including wind direction and speed, cloud cover, tide condition, times of the day (before and after sunset) were recorded during experiments. Generalized linear models were used to detect the effects of endogenous and exogenous factors on the migratory motivation of the birds. Results In the south Yellow Sea, the migratory activity intensity of Great Knots was positively related to wind assistance. In the north Yellow Sea, where birds exhibited higher intensity of migratory activity than in the south, the intensity increased and the motivation to initiate migration grew stronger as the season advanced. The Great Knots exhibited wind-related orientation behaviour in the funnels at both sites. Conclusions The results suggest that the intensity of migratory motivation differed between the two sites. Departure decisions of Great Knots appear to be affected mainly by external factors at the temporary rest site in the south Yellow Sea but possibly by endogenous factors at the final pre-breeding refuelling site in the north Yellow Sea.

The fast economic development of the People&rsquo, s Republic of China has created an increasing demand for usable land, resulting in large-scale land reclamations along the coastal zone. One of these regions is Tongzhou Bay (Jiangsu coast), a region characterized by large intertidal mudflats and deep tidal channels with potential for the development of agri-aquaculture and the construction of a deep-sea port. However, these intertidal mudflats also provide vital ecosystem services and support many wildlife species, including several endangered migratory shorebirds within the East Asian&ndash, Australasian Flyway. With increasing realization of the importance of maintaining such ecological values, a more integrated coastal development strategy is needed. This study aims to develop a sustainable integrated design for the Tongzhou Bay port, following a &ldquo, Building with Nature&rdquo, approach. We use a morphodynamic model to compute habitat suitability for two shorebird species (Great Knot Calidris tenuirostris and Bar-tailed Godwit Limosa lapponica). Several port configurations were developed on the basis of three design criteria: (1) create area for future port development, whilst (2) preserving existing high-value ecotopes for shorebirds and (3) enhance the natural accretion rate of such ecotopes. Simulation results showed a clear difference in siltation patterns, preservation and enhancement of preferred ecotopes. This work therefore demonstrates the potential and importance of morphological and habitat suitability modelling when designing large-scale reclamations and port constructions, especially in dynamic areas such as Tongzhou Bay.

The Yellow Sea coastline in East Asia, an important staging area for migratory shorebirds in the East Asian-Australasian Flyway (EAAF), is rapidly deteriorating. Conserving the declining shorebird populations that rely on the Yellow Sea requires habitat protection and management based on sound ecological knowledge, especially on the seasonal occurrence of shorebirds, their daily movements and their food resources. However, in this region such ecological data are scarce, and expertise to collect them are less-established. Here we gather and assimilate such information for the coastal wetlands at Lianyungang on the Chinese Yellow Sea coast, an understudied and unprotected area where we found 27% of intertidal soft sediment habitats have been destroyed in 2003–2018 by reclamation. In 2008–2018, 43 shorebird species were recorded along this coastline, including 12 globally threatened or ‘Near Threatened’ species. In terms of number of shorebird species exceeding 1% of the EAAF population, with 22 species meeting this criterion, Lianyungang ranks highest among the >300 shorebird sites in East Asia. The benthic mollusc community of the intertidal flats were dominated by small soft-shelled bivalve species at very high densities, including 9399 individuals/m2 of Potamocorbula laevis, which are high-quality food for shorebirds to refuel during migration. Satellite tracked bar-tailed godwits (Limosa lapponica) and great knots (Calidris tenuirostris) stopped at Lianyungang for 5–30 days during northward and southward migration. The tidal movements of satellite-tagged birds indicated high-tide roosts and low-tide foraging areas, some of which are inaccessible on-ground. These movements can also be used to evaluate whether roosts and foraging areas are close enough to each other, and direct where to create new roost sites. Potential measures to increase the capacity of Lianyungang to support shorebirds include reducing human disturbances, creating roosts at undeveloped parts of the reclaimed land, and removing recently-built sea dikes to restore intertidal flats. Keywords: East Asian-Australasian Flyway, Intertidal mudflats, Shorebirds, Reclamation, Satellite tracking, Yellow Sea

Organisms cope with environmental stressors by behavioral, morphological, and physiological adjustments. Documentation of such adjustments in the wild provides information on the response space in nature and the extent to which behavioral and bodily adjustments lead to appropriate performance effects. Here we studied the morphological and digestive adjustments in a staging population of migrating Great Knots Calidris tenuirostris in response to stark declines in food abundance and quality at the Yalu Jiang estuarine wetland (northern Yellow Sea, China). At Yalu Jiang, from 2011 to 2017 the densities of intertidal mollusks, the food of Great Knots, declined 15-fold. The staple prey of Great Knots shifted from the relatively soft-shelled bivalve Potamocorbula laevis in 2011–2012 to harder-shelled mollusks such as the gastropod Umbonium thomasi in 2016–2017. The crushing of the mollusks in the gizzard would require a threefold to 11-fold increase in break force. This was partially resolved by a 15% increase in gizzard mass which would yield a 32% increase in shell processing capacity. The consumption of harder-shelled mollusks was also accompanied by reliance on regurgitates to excrete unbreakable parts of prey, rather than the usual intestinal voidance of shell fragments as feces. Despite the changes in digestive morphology and strategy, there was still an 85% reduction in intake rate in 2016–2017 compared with 2011–2012. With these morphological and digestive adjustments, the Great Knots remaining faithful to the staging site to a certain extent buffered the disadvantageous effects of dramatic food declines. However, compensation was not complete. Locally, birds will have had to extend foraging time and use a greater daily foraging range. This study offers a perspective on how individual animals may mitigate the effects of environmental change by morphological and digestive strategies and the limits to the response space of long-distance migrating shorebirds in the wild.

Competition intensity depends on the number of competitors and the amount of resources available. Coexistence of potential competitors can be enabled through niche differentiation or high resource availability. Using diet analysis, we investigated which of these 2 mechanisms was in play for coexisting shorebirds at a major staging site in the northern Yellow Sea, China, during northward migration in 2011 and 2012. Competition for food at this site is expected to be intense, with an estimated 250,000 migratory shorebirds gathering annually to refuel over a short period. Great Knots (Calidris tenuirostris), Eurasian Oystercatchers (Haematopus ostralegus osculans), and Red Knots (C. canutus) selected mostly the bivalve Potamocorbula laevis, whereas Bar-tailed Godwits (Limosa lapponica) had a broader diet and showed selection for polychaetes, even though most of their biomass intake was of P. laevis. Although all of these shorebirds fed on P. laevis, they showed different size selection and used diff...

Saemangeum, in the Republic of Korea (ROK, commonly called South Korea) was one of the most important shorebird staging sites in the Yellow Sea. It supported at least 330000 shorebirds annually between 1997 and 2001, including ~30% of the world population of Great Knots (Calidris tenuirostris) during both northward and southward migration. Construction of a 33-km long sea-wall was completed in April 2006. We show that shorebird numbers at Saemangeum and two adjacent wetlands decreased by 130000 during northward migration in the next two years and that all species have declined at Saemangeum since completion of the sea-wall. Great Knots were among the most rapidly affected species. Fewer than 5000 shorebirds were recorded at Saemangeum during northward migration in 2014. We found no evidence to suggest that most shorebirds of any species displaced from Saemangeum successfully relocated to other sites in the ROK. Instead, by 2011–13 nearly all species had declined substantially in the ROK since previous national surveys in 1998 and 2008, especially at more heavily reclaimed sites. It is likely that these declines were driven by increased mortality rather than movement to alternate staging sites given that other studies have shown concurrent declines in numbers and survival on the non-breeding grounds. This is the first study in the East Asian–Australasian Flyway to confirm declines of shorebirds at a range of geographical scales following a single reclamation project. The results indicate that if migratory shorebirds are displaced from major staging sites by reclamation they are probably unable to relocate successfully to alternate sites.

Because migration is highly time-constrained and migration timing varies among individuals, the responses of migrants to food shortage at a refuelling site could differ between individuals that arrive early and late at the site. To test this hypothesis, we compared the stopover decision, in terms of occurrence and length of stay (LOS), of radiotagged Great Knots Calidris tenuirostris before (2012) and after (2015) a dramatic decline in food supply at a critical spring final pre-breeding refuelling site in the northern Yellow Sea. The probability of occurrence at the refuelling site was consistent between the two years, whereas the average LOS significantly shortened in the year of food shortage in late-arriving individuals. This suggests migration timing intensifies the influence of food shortage in late-arriving individuals, which might be more sensitive and vulnerable to food shortage at refuelling sites compared with early-arriving individuals.

Especially in birds, it is widely found that the size of individual prey items follows the size of the instruments of prey capture, handling and processing, i.e. bill size. In fact, this is the natural history basis of major discoveries on adaptive evolution in the face of changing food resources. In some birds, e.g. the molluscivore shorebirds ingesting hard‐shelled prey, most of the prey processing takes place within the digestive tract. This study of a salvaged sample of actively feeding great knots Calidris tenuirostris accidentally drowned in fishing nets in northern China, is the first documentation of diet selection at the level of the individual in previously well‐studied molluscivore shorebirds. Diet composition was not associated with the length of the bill, but with the mass of the muscular gizzard. Gizzard mass, which unlike bill length is a phenotypically flexible trait, enables great knots to adjust to changing food resources as an individual, i.e. instantly responding to the food on offer. For migratory species like great knots which rely on seasonal sequences of interdistant feeding areas offering prey with a variety of characteristics, the capacity to individually adjust appears a key adaptation.

BackgroundDeparture decisions and behaviors of migratory birds at stopover sites are expected to maximize fitness by trade-offs among avoiding predators, optimizing refueling (energy) capacity, and matching other life-history events. We predict that species with different body sizes and migratory destinations will exhibit different behaviors when departing from the same stopover site. We also predict that with strong time constraint at the final pre-breeding stopover site, departure decisions may be less sensitive to exogenous factors, such as wind condition, compared to other stopover or nonbreeding sites.MethodsWe recorded migratory departures of four shorebird species, i.e. Eurasian Curlew (Numenius arquata), Bar-tailed Godwit (Limosa lapponica), Great Knot (Calidris tenuirostris), and Grey Plover (Pluvialis squatarola), at Yalujiang Estuary Wetlands in China, a final pre-breeding stopover site in the northern Yellow Sea, from 2011 to 2014. We compared flock sizes, departure time and departure directions between species, and investigated the effects of tide and weather conditions (rain and ground wind speed and direction) on the departure decision of shorebirds.ResultsWe found that larger species departed in smaller flocks and were more variable in daily departure time. Departure trajectory of all four species appeared to be influenced by coastal topography. With the east–west coastline and intertidal mudflat on the south, birds exhibited westward or eastward deflection from the shortest migratory routes. Bar-tailed Godwit was the only species that deviated to the southeast and did not climb over the land. Birds avoided departure during precipitation, while their departure was not related to ground wind benefit or tidal condition.ConclusionsBody size among species, which influences their vulnerability to predators, might be important in shaping shorebird departure strategies. Diverse departure directions could be the result of different wind use tactics in climbing stage. Narrow optimal time window of breeding might lead to reduced flexibility in departure date at a final pre-breeding site. Both endogenous and exogenous are important in shaping departure behaviors and decisions.

SummaryMany shorebird populations are in decline along the East Asian-Australasian Flyway. The rapid loss of coastal wetlands in the Yellow Sea, which provide critical stop-over sites during migration, is believed to be the cause of the alarming trends. The Yalu Jiang coastal wetland, a protected area in the north Yellow Sea, supports the largest known migratory staging populations of Bar-tailed Godwits Limosa lapponica (menzbieri and baueri subspecies) and Great Knots Calidris tenuirostris. Monitoring of the macrozoobenthos food for these shorebirds from 2011 to 2016 showed declines of over 99% in the densities of the bivalve Potamocorbula laevis, the major food here for both Bar-tailed Godwits and Great Knots. The loss of the bivalve might be caused by any combination of, but not limited to: (1) change in hydrological conditions and sediment composition due to nearby port construction, (2) run-off of agrochemicals from the extensive shoreline sea cucumber farms, and (3) parasitic infection. Surprisingly, the numbers of birds using the Yalu Jiang coastal wetland remained stable during the study period, except for the subspecies of Bar-tailed Godwit L. l. menzbieri, which exhibited a 91% decline in peak numbers. The lack of an overall decline in the number of bird days in Great Knots and in the peak numbers of L. l. baueri, also given the published simultaneous decreases in their annual survival, implies a lack of alternative habitats that birds could relocate to. This study highlights that food declines at staging sites could be an overlooked but important factor causing population declines of shorebirds along the Flyway. Maintaining the quality of protected staging sites is as important in shorebird conservation as is the safeguarding of staging sites from land claim. Meanwhile, it calls for immediate action to restore the food base for these beleaguered migrant shorebirds at Yalu Jiang coastal wetland.

Selection of timing to match optimal environments is crucial for migrants that breed at high latitudes where there is a narrow time window suitable for breeding. However, birds generally depart from non-breeding grounds in a broad time window. How birds adjust their migration schedule to match optimal timing of arrival at breeding grounds is largely unexplored. We radio-tracked Great Knots Calidris tenuirostris at stopping sites in the southern and northern Yellow Sea during the entire stopping periods to determine their time schedules during northward migration. Great Knots stayed for 40.7 ± 9.2 days (n = 11) in the whole Yellow Sea, with the early arrivals having a longer length of stay than the late arrivals. There was no significant difference in the length of stay between birds that arrived on various dates in the southern Yellow Sea, while the late arrivals spent less time during flights from the southern to the northern Yellow Sea, and stayed for a shorter time than the early arrivals in the northern Yellow Sea. We estimated that the later arrivals can still moult into full breeding plumage and deposit enough fuel for a flight to the breeding grounds before departure. We propose that early and latter migration are the two ends of migratory schedule, with the former adapting to unpredictable and rigorous environments and the latter to stable and favourable environments en route. Stopping sites play an important role for birds to adjust their migration schedule to meet optimal timing of arrival at migratory destination.

Migratory animals are threatened by human-induced global change. However, little is known about how stopover habitat, essential for refuelling during migration, affects the population dynamics of migratory species. Using 20 years of continent-wide citizen science data, we assess population trends of ten shorebird taxa that refuel on Yellow Sea tidal mudflats, a threatened ecosystem that has shrunk by >65% in recent decades. Seven of the taxa declined at rates of up to 8% per year. Taxa with the greatest reliance on the Yellow Sea as a stopover site showed the greatest declines, whereas those that stop primarily in other regions had slowly declining or stable populations. Decline rate was unaffected by shared evolutionary history among taxa and was not predicted by migration distance, breeding range size, non-breeding location, generation time or body size. These results suggest that changes in stopover habitat can severely limit migratory populations., Stopover sites are crucial to migratory birds, but the influence of this habitat on population dynamics has not been quantified. Here, Studds et al. show that, among ten migratory species, the degree of reliance on disappearing stopover habitat in the Yellow Sea tidal flats predicts the extent of recent population declines.

Migratory shorebird species depend on a suite of interconnected sites and protection of these sites as part of a network is an increasingly used conservation approach. Partnering sites based on shared migratory bird species can be a powerful tool for implementing conservation action. To assist the Adelaide International Bird Sanctuary (AIBS), South Australia, in expanding their conservation impact across the East Asian-Australasian Flyway, we generated a list of 81 sites to consider for potential partnerships. We developed the list using existing shorebird count data for seven high priority migratory shorebirds that spend the austral summer at AIBS, such as Bar-tailed Godwit (Limosa lapponica) and Great Knot (Calidris tenuirostris). We computed a scaled abundance across all species to develop a categorical indicator of importance of each potential site for its shared species richness and abundance. Based on assessments of literature, existing conservation plans, and interviews with experts, we also evaluated each potential site’s feasibility for ecotourism, conservation management, and existing or potential partnerships. This process resulted in a list of 20 sites for the AIBS to consider for possible partnerships in nine countries that met some combination of values for shared shorebird species, inclusion in one or more current site designation schemes, existing or potential opportunities for tourism, habitat management, or partnerships. Additional sites that either have high or medium abundances of shared shorebird species or that have been designated as important by other criteria (Ramsar, Important Bird and Biodiversity Area) were identified. We recommend this methodology be applied to other sites seeking to form cross-boundary partnerships to help further the conservation of highly mobile species.

SummaryBar-tailed Godwits Limosa lapponica and Great Knots Calidris tenuirostris are long-distance migratory shorebirds with declining numbers in the East Asian-Australasian Flyway. One of the most important staging sites for these two species during northward migration is Yalu Jiang coastal wetland in the north Yellow Sea. Historical counts have been limited to once a year and conducted at different periods; these yield inadequate data for population monitoring. We estimated the numbers of Bar-tailed Godwits and Great Knots and described their migration phenology during northward migration from 2010 to 2012 at the Yalu Jiang coastal wetland, using a combination of periodic area-wide counts over the migration period and a modelling approach that estimates passage times and total numbers of birds transiting. The mean arrival date for L. l. baueri godwits was 29 March and mean departure date was 8 May. Corresponding dates were 11 April and 15 May for L. l. menzbieri godwits and 7 April and 14 May for Great Knots. We estimated that an annual average of over 68,000 Bar-tailed Godwits and 44,000 Great Knots used the area on northward migration from 2010–2012. Our results indicate that the Yalu Jiang coastal wetland supports on average at least 42% of the flyway’s northward-migrating L. l. baueri godwits, 19% of L. l. menzbieri godwits, and 22% of the Great Knots. Comparisons with historical counts conducted during peak migration periods indicate a 13% decline in Bar-tailed Godwits since 2004 and an 18% decline in Great Knots since 1999. Our results confirm that the study area remains the most important northward migration staging site for Bar-tailed Godwits and indicate that it has become the most important northward migration staging site for Great Knots along the flyway.

In the Yellow Sea region of East Asia, tidal wetlands are the frontline ecosystem protecting a coastal population of more than 60 million people from storms and sea-level rise. However, unprecedented coastal development has led to growing concern about the status of these ecosystems. We developed a remote-sensing method to assess change over ~4000 km of the Yellow Sea coastline and discovered extensive losses of the region's principal coastal ecosystem – tidal flats – associated with urban, industrial, and agricultural land reclamations. Our analysis revealed that 28% of tidal flats existing in the 1980s had disappeared by the late 2000s (1.2% annually). Moreover, reference to historical maps suggests that up to 65% of tidal flats were lost over the past five decades. With the region forecast to be a global hotspot of urban expansion, development of the Yellow Sea coastline should pursue a course that minimizes the loss of remaining coastal ecosystems.

The Great Knot Calidris tenuirostris is one of the iconic long-distance migratory species of the East Asian-Australasian Flyway. However, despite extensive flagging and banding efforts, very little is known about the migratory strategies and the breeding grounds of this species that spends the non-breeding season mainly on the northern shorelines of Australia. Using light-level geolocators deployed on Great Knots at Roebuck Bay (Western Australia), we describe the individual migration strategies, breeding locations and breeding-related behaviour. Based on data from eight successfully tracked individuals, we found that all except one migrated to the western part of the known breeding range. This was 2,000–2,500 km from the eighth individual that commenced breeding in the potentially sep- arated eastern part of the range. Light intensity and temperature profiles provided evidence that four of the birds successfully hatched chicks. Of the three which failed, one appeared to have laid a second clutch before failing again. Arrival at the breeding grounds and the laying of eggs were remarkably synchronous between individuals, as were the arrival dates back at Roebuck Bay. Departure from the breeding grounds was more spread out, partly dependent on breeding success and also as a result of females probably leaving the nesting area before males. The individual migration strategies confirmed the strong dependence of this species on the Yellow Sea as their major stopover site during both southward and northward migration. Furthermore, all individuals stopped at least once on their northward journey to the Yellow Sea from Australia. And in reverse, all individuals stopped at least once on the southward migration before arriving at the Yellow Sea coming from their Arctic breeding grounds. The results indicate that this species will most likely be further affected by the rapid habitat loss in the area of the Yellow Sea and other parts of the Chinese coastline.

espanolEl presente informe publica 247 registros estudiados y aceptados por el Comite de Rarezas, relativos a la presencia de 93 taxones de aves raras en el conjunto de Espana. El indice de aceptacion de las citas obtenidas se ha situado en el 92%. Las citas mas destacadas incluidas en el presente informe son las de correlimos grande Calidris tenuirostris –primera para Espana–, cuervo deserticola Corvus ruficollis –primera para Espana–, la subespecie centroeuropea de mito Aegithalos caudatus europaeus –primera para Espana–, pardillo norteno Acanthis flammea flammea –primera para Espana–, cuclillo piquicualdo Coccyzus americanus –segunda para Espana–, zarapito trinador americano Numenius hudsonicus –segunda para Espana–, alcaudon meridional estepario Lanius meridionalis pallidirostris –segunda para Espana–, gaviota cocinera Larus dominicanus –tercera cita para Espana– y correlimos zancolin Calidris himantopus –tercera para Espana. Ademas, se recogen un buen numero de observaciones con interes a nivel regional. Entre ellas destacan las observaciones de petrel gon gon Pterodroma feae –segunda para Espana peninsular–, barnacla carinegra Branta bernicla –un ejemplar de la subespecie groenlandesa hrota, segunda para Canarias–, piquero pardo Sula leucogaster –segunda y tercera para Canarias–, charran sombrio Onychoprion fuscatus –segunda y tercera para Canarias– y charran real Sterna maxima –segunda para Canarias. Tambien se recogieron numeros sin precedentes de pardillo alpino Acanthis flammea cabaret y alondra ibis Alaemon alaudipes, ademas del primer caso de nidificacion en Espana de corneja cenicienta Corvus cornix y un nuevo caso de reproduccion de corredor sahariano Cursorius cursor. Por ultimo, se ha proseguido con la revision de citas relevantes homologadas en el pasado, utilizando los nuevos criterios de identificacion. En este sentido, se rechazan las dos observaciones de avefria coliblanca Vanellus leucurus homologadas en Espana (lo que significa la salida de la especie de la Lista Patron), asi como algunas citas de tarabilla siberiana Saxicola maurus, una cita de gaviota cocinera Larus dominicanus, una de halcon sacre Falco cherrug y una de correlimos acuminado Calidris acuminata. EnglishThis report published 247 records studied and accepted by the Rarities Committee concerning the presence of 93 taxa of rare birds in the whole of Spain. The rate of acceptance of quotations obtained stood at 92%. The most important events included in this report are those of large sandpipers great knot -first to Spain-, desert-brown-necked raven crow -first to Spain- Central European subspecies of long-tailed tit myth europaeus -first to Spain- northern pardillo Acanthis flammea flammea -first to Spain-, yellow-billed cuckoo cuckoo piquicualdo -second to Spain- curlew Numenius American trinador hudsonicus -second to Spain-, southern Shrike southern Gray Shrike estepario -second pallidirostris for Spain- Kelp Gull Kelp Gull -third appointment to Spain- and stilt sandpiper sandpipers zancolin -third to Spain. In addition, a number of observations are collected with interest at the regional level. These include observations of Fea's Petrel petrel gon gon -second for the Peninsular Spain, brent goose Branta bernicla -a copy of the Greenlandic subspecies hrota, second to Canary, brown booby Sula leucogaster -second and third for Canary, dark tern sooty tern -second and third for Canaries and royal tern Sterna maxima -second for the Canaries. record numbers Alpine pardillo Acanthis flammea cabaret and lark ibis Alaemon alaudipes were also collected, in addition to the first case in Spain of nesting hooded crow Hooded Crow and a new case Cream-colored reproduction Cursorius cursor. Finally, it has continued with the review of relevant citations approved in the past, using new identification criteria. In this regard, the two observations of white-tailed lapwing white-tailed lapwing approved in Spain (which means the departure of the species of the Pattern List), as well as some quotes from Siberian Stonechat Saxicola maurus, a quote from Kelp Gull Kelp Gull rejected, a saker falcon Falco cherrug and sandpipers Calidris acuminata one of acuminata.

This study was conducted between March and July of 2010 in the area of Yubudo (Is.) in order to assess its avian fauna. A total of 39,121 counts of 37 species were observed over 5 sessions. Important dominant species included the dunlin (Calidris alpine) (48.0%), followed by the bar-tailed godwit (Limosa lapponica) (26.2%), far eastern curlew (Numenius madagascariensis) (5.2%) and the great knot (Calidris tenuirostris) (5.1%). Among the dominant species, the dunlin and the bar-tailed godwit showed significant increase in count, while the great knot showed a decrease. The far eastern curlew, eastern oystercatcher (Haematopus ostralegus) and the Indian curlew (Numenius arquata) did not show any significant difference when compared to previous studies, in terms of both migratory bird count and migratory pattern. Such migratory pattern of dominant species seems to be the result of large scale environmental changes.

We compared seasonal variations in body condition and fuel deposition patterns of five calidrid sandpipers at Chongming Dongtan (eastern China), a stopover site in the East Asian—Australasian Flyway. We tested the hypothesis that long-distance migrants show different body condition and fuel deposition patterns relative to those undertaking short-distance flights. Results indicated that the body condition and fuel deposition patterns of the sandpipers varied between the northward and southward migration seasons and between age-classes. Great Knots Calidris tenuirostris and Red Knots Calidris canutus migrate southwards on a long-distance nonstop flight from Chongming Dongtan to northwest Australia, while covering on the return flight a relatively short-distance between Chongming Dongtan and the north Yellow Sea region. Both species attained a significantly higher body condition at Chongming Dongtan during the southward than northward migration. Moreover, they showed a significant increase in body condition ...

Iron, zinc, copper, lead, and cadmium were measured in livers of three shorebird species from Okgu Mudflat, Korea in the East Asian-Australian migration flyways. Iron concentrations in red-necked stints (Calidris ruficollis) (geomean = 1,322 microg/g dw) were higher than in terek sandpipers (Xenus cinereus) (467 microg/g dw), and great knots (Calidris tenuirostris) (158 microg/g dw). Copper concentrations in great knots (85.8 microg/g dw) were significantly higher than in red-necked stints (15.9 microg/g dw) and terek sandpipers (10.4 microg/g dw). However, significant differences in zinc concentrations were not found in livers among shorebird species. Iron, zinc, and copper concentrations from this study were within the range of other shorebird studies. We suggest that essential elements such as iron, zinc, and copper are within normal range and are maintained there by normal homeostatic mechanism. Lead and cadmium concentrations differed among shorebird species; red-necked stints (geomeans 27.8 microg/g dw and 4.69 microg/g dw, respectively) were higher than in terek sandpipers (12.9 and 0.44 microg/g dw, respectively), and great knots (5.43 and 0.29 microg/g dw, respectively). Some red-necked stints exceeded toxic levels of lead and cadmium for wild birds. In livers of red-necked stints from Okgu Mudflat, lead and cadmium concentrations were higher than previously reported in other shorebirds.

There is increasing concern about the world’s animal migrations. With many land-use andclimatological changes occurring simultaneously, pinning down the causes of large-scale conservationproblems requires sophisticated and data-intensive approaches.2. Declining shorebird numbers along the East Asian–Australasian Flyway, in combinationwith data on habitat loss along the Yellow Sea (where these birds refuel during long-distancemigrations), indicate a flyway under threat.3. If habitat loss at staging areas indeed leads to flyway-wide bird losses, we would predictthat: (i) decreases in survival only occur during the season that birds use the Yellow Sea, and(ii) decreases in survival occur in migrants that share a reliance on the vanishing intertidalflats along the Yellow Sea, even if ecologically distinct and using different breeding grounds.4. Monitored from 2006–2013, we analysed seasonal apparent survival patterns of threeshorebird species with non-overlapping Arctic breeding areas and considerable differences inforaging ecology, but a shared use of both north-west Australian non-breeding grounds andthe Yellow Sea coasts to refuel during northward and southward migrations (red knot Calidriscanutus piersmai, great knot Calidris tenuirostris, bar-tailed godwit Limosa lapponicamenzbieri). Distinguishing two three-month non-breeding periods and a six-month migrationand breeding period, and analysing survival of the three species and the three seasons in asingle model, we statistically evaluated differences at both the species and season levels.5. Whereas apparent survival remained high in north-west Australia, during the time awayfrom the non-breeding grounds survival in all three species began to decline in 2011, havinglost 20 percentage points by 2012. By 2012 annual apparent survival had become as low as0?71 in bar-tailed godwits, 0?68 in great knots and 0?67 in red knots. In a separate analysisfor red knots, no mortality occurred during the migration from Australia to China. In thesummers of low summer survival, weather conditions were benign in the Arctic breedingareas.6. We argue that rapid seashore habitat loss in the Yellow Sea is the most likely explanation ofreduced summer survival, with dire (but uncertain) forecasts for the future of these flyway populations.This interpretation is consistent with recent findings of declining shorebird numbers atseemingly intact southern non-breeding sites.7. Policy implications. Due to established economic interests, governments are usually reluctantto act for conservation, unless unambiguous evidence for particular cause–effect chainsis apparent. This study adds to an increasing body of evidence that habitat loss along theYellow Sea shores explains the widespread declines in shorebird numbers along the EastAsian–Australasian Flyway and threatens the long-term prospects of several long-distancemigrating species. To halt further losses, the clearance of coastal intertidal habitat must stop now.

China’s coastal wetlands belong to some of the most threatened ecosystems worldwide. The loss and degradation of these wetlands seriously threaten waterbirds that depend on wetlands. The China Coastal Waterbird Census was organized by volunteer birdwatchers in China’s coastal region. Waterbirds were surveyed synchronously once every month at 14 sites, as well as irregularly at a further 18 sites, between September 2005 and December 2013. A total of 75 species of waterbirds met the 1 % population level Ramsar listing criterion at least once at one site. The number of birds of the following species accounted for over 20 % of the total flyway populations at a single site: Mute Swan (Cygnus olor), Siberia Crane (Grus leucogeranus), Far Eastern Oystercatcher (Haematopus osculans), Bar-tailed Godwit (Limosa lapponica), Spotted Greenshank (Tringa guttifer), Great Knot (Calidris tenuirostris), Spoon-billed Sandpiper (Calidris pygmeus), Saunders’s Gull (Larus saundersi), Relict Gull (Larus relictus), Great Cormorant (Phalacrocorax carbo), Eurasian Spoonbill (Platalea leucorodia), Black-faced Spoonbill (Platalea minor) and Dalmatian Pelican (Pelecanus crispus). A total of 26 sites supported at least one species of which their number met the 1 % criterion. Forty-two species met the 1 % criterion in the Yellow River Delta, Shandong; 29 at the Cangzhou coast, Hebei and 26 species at the Lianyungang coast, Jiangsu. The results highlight the international importance of China’s coastal wetlands for waterbirds. This study also demonstrates that participation of local birdwatchers in waterbird surveys results in data that are invaluable not only for understanding the current status of waterbirds in China’s coastal regions but also for waterbird conservation and management.

High tides force shorebirds from their intertidal feeding areas to refuges known as roosts. This paper explores the energetic costs of roost disturbance of great knot (Calidris tenuirostris) and red knot (C. canutus) at Roebuck Bay, North-western Australia, assessing disturbance levels at different roost sites through direct observation and automatic radio-telemetry, and applying physiological equations and predictive roost choice models to estimate energetic costs of disturbance through a complete tidal cycle. The study area had a variety of roosts, but use of each was constrained by conditions of tide and time. The roost most suitable for shorebirds on daytime high tides of intermediate height experienced high levels of disturbance from both natural sources (birds of prey) and humans. Flight costs caused by disturbance at this site exceeded the costs of flying to and roosting at the nearest alternative roost, 25 km away. However, shorebirds did not roost at the alternate site, possibly because of the risk of heat stress in a prolonged flight in tropical conditions. Increases in disturbance levels at just one of the roost sites of Roebuck Bay would increase energetic costs substantially, and could easily reach the point at which feeding areas accessed from this roost cannot be used without incurring a net energy deficit. Roost availability can therefore limit access to feeding areas and hence limit population size. Adequate provision and management of roost sites is accordingly an important consideration in conservation of sites used by coastal shorebirds. (c) 2006 Elsevier Ltd. All rights reserved.

The mouth of the Yangtze River is an important stopover site for migratory shorebirds using the East Asian-Australasian Flyway. From 1984 to 2004, we censused and banded shorebirds and monitored hunting activities at the mouth of the Yangtze River to understand how shorebirds used the study area. Counts and banding data revealed greater numbers of shorebirds at the mouth of the Yangtze River during northward migration (spring) than during southward migration (fall), with ratios varying from 1.5:1 to 7.2:1 at different sites from 1984 to 2005. The most common species observed during spring (northward) migration were Great Knots (Calidris tenuirostris), Red Knots (Calidris canutus), Bar-tailed Godwits (Limosa lapponica), Sharp-tailed Sandpipers (Calidris acuminata), and Red-necked Stints (Calidris ruficollis). During spring 2003–2004, 96.98% of the shorebirds observed were adults (ASY or older) and 3% were after hatching-year and second-year birds (AHY or SY). In contrast, almost all (94.73%) birds counted during the fall were hatching-year (HY) birds. These results indicate that adult shorebirds either use a different migration route during fall migration or use the same route, but do not stop at the mouth of the Yangtze River. HY birds, however, may depend on the coastal stopover sites for feeding during their first southward passage. SINOPSIS La desembocadura del Rio Yangtze es un importante punto de parada de playeros migratorios que utilizan la via del Este-Asiatico-Australasico. De 1984 to 2004 anillamos playeros y se condujeron censos para monitorear las actividades de caceria en la desembocadura del Yangtze y ademasdeterminar como los playeros utilizaban dicha area. Los conteos de aves anilladas revelaron un mayor numero de playeros durante la migracion hacia el norte (primaveral) que durante la migracion hacia el sur (otonal) con una tasa de 1.5:1 a 7.2:1 en diferentes localidades. Las especies que se observaron con mayor frecuencia durante la primavera (moviendose hacia el norte) fueron Calidris tenuirostris, C. canutus, C. acuminata, C. ruficollis y Limosa lapponica. Durante la primavera del 2003–2004, el 96.98% de las aves observadas fueron adultos y el 3% fueron aves de segundo ano o juveniles del primer ano. En contraste el 94.73% de las aves contabilizadas durante el otono fueron juveniles del primer ano. Estos resultados indican que los adultos utilizan otra ruta durante la migracion otonal o una ruta similar pero que no paran en la desembocadura del Yangtze. Sin embargo, las aves de primer ano muy bien pudieran depender de los recursos alimentarios de los puntos de parada costaneros durante su primer viaje hacia el sur.

We studied the prebreeding moult and resulting plumage in a long-distance migrant sandpiper (Scolopacidae), the Great Knot Calidris tenuirostris , on the non-breeding grounds (northwest Australia), on arrival at the staging grounds after the first migratory flight (eastern China) and on or near the Russian breeding grounds (Russian data from museum specimens). We show that breeding plumage scores and breast blackness were affected not only by the increase in moulted feathers but also in the wearing down of overlaying pale tips of fresh feathers. Birds migrating from Australia and arriving in China had completed or suspended moult, but more moult must occur in Asia as Russian specimens had moulted more of their mantle and scapular feathers. Russian birds had significantly more red feathering on their upperparts than had birds in Australia or those arriving in China. The increase in reddish feathers cannot by accounted for simply by continuation of the prealternate moult. Instead, a third, presupplemental moult must occur, in which red-marked feathers replace some scapular and especially mantle feathers that were acquired in a prealternate moult only 1‐3 months earlier. Great Knot sexes show little size and plumage dimorphism, whereas two other sandpipers that have supplemental plumages (Ruff Philomachus pugnax and Bartailed Godwit Limosa lapponica ) are thought to be highly sexually selected. Bidirectional sexual selection may therefore be involved in the evolution of a supplemental plumage in Great Knots.

Coastal regions are important habitats for migratory shorebirds. The aim of the study is to understand habitat use by migratory shorebirds and to develop a conservation strategy in the sustainable use of wetlands. From March 2004 to January 2005, we conducted a seasonal shorebirds census in ten coastal habitats along the South Yangtze River mouth and North Hangzhou Bay, simultaneously examining the relative seasonal abundance of shorebirds and their spatial distribution. A total of 25 species were identified, the dominant seasonal species were Great Knot ( Calidris tenuirostris ), Sharp-tailed Sandpiper ( Calidris alpine ) and Red-necked Stint ( Calidris ruficollis ) in spring; Kentish Plover ( Charadrius alexandrinus ), Common Greenshank( Tringa nebularia ) and Lesser Sand Plover ( Charadrius mongolus ) in summer; Kentish Plover, Red-necked Stint and Common Greenshank in autumn; Dunlin( Calidris alpine ), Kentish Plover and Marsh Sandpiper ( Tringa stagnatilis ) in winter. These species accounted for more than 85% of the total shorebirds. The numbers of shorebirds counted was highest in spring and then in autumn, winter and summer respectively. Among the four seasons, there were few significant differences in the number of bird species between the sites outside the seawall (intertidal mudflat) and the sites inside the seawall (artificial wetland), but the average density of shorebirds was obviously different. The habitat-selection analysis of the environmental factors (outside and inside the seawall) impacting on the shorebird community was made in the 10 study sites with Canonical Correspondence Analysis. The study results indicated that: (1) Outside the seawall, the widths of the total intertidal mudflat and bare mudflat were the key factors affecting the shorebirds; the proportion of bulrush ( Scirpus×mariquete ) covering and supertidal mudflat width had a positive correlation with the abundance of birds, while human disturbance and the proportion of both reed ( Phragmites communis ) and smooth cord-grass ( Spartina alterniflora ) covering in total surveyed areas had negative impacts on bird numbers; (2) Inside the seawall, the proportions of areas with shallow water and mudflats occupying the total surveyed area were key factors influencing the number of birds; the size of the bulrush area should have a positive impact on the appearance of shorebirds. Habitats with heavy human disturbance, dense reed and smooth cord-grass or a high water level were not conducive to be inhabited by shorebirds.

Shorebirds held during banding activities can develop muscle cramps, especially when temperatures are high and birds are heavy. Such capture myopathy can be fatal or render birds vulnerable to predators. We rehabilitated Great Knots (Calidris tenuirostris), Red Knots (C. canutus), Bar-tailed Godwits (Limosa lapponica), and Red-necked Stints (C. ruficollis) in northwestern Australia. We kept birds in slings (if cramped) or in a small cage (if able to walk) and gave them daily standing exercises. Recovery of severely cramped birds took up to 14 d, which may reflect a critical period of tissue regeneration. Of 15 knots (8 Red and 7 Great) taken into captivity, 12 were rehabilitated and released. The resighting rate after the breeding season of the rehabilitated birds was the same as for other birds color-banded during our research, indicating that the rehabilitation was successful. We conclude that rehabilitating cramped shorebirds is possible though time-consuming. A sex bias in susceptibility to c...

It is often assumed that strong selection pressures give rise to trade-offs between body condition and time in long-distance migrating birds. Birds that are 'behind schedule' in fuel deposition or moult should delay departure, and this should result in a negative correlation between initial condition and departure date. We tested this hypothesis in the Great Knot Calidris tenuirostris migrating from north-west Australia to eastern Asia en route to Siberia. Great Knot gain mass and moult into breeding plumage before leaving northern Australia in late March and early April, and fly 5400-6000 km to eastern China and Korea. We radiotracked 27 individuals (17 males and ten females) to determine departure dates; 23 migrated and four remained in Australia. We characterized body condition at capture using body mass, predicted pectoral muscle mass (based on ultrasound estimates of the size of the pectoral muscles) and breeding plumage scores. Residual condition indices were uncorrelated, indicating that at the individual level, variation in one fuelling component was not strongly associated with variation in the other components. Birds that did not depart had lower residual body mass and breeding plumage indices than those that did migrate; these four birds may have been subadults. Neither sex, size nor the condition indices explained variation in departure date of migrants. Reasons for this are explored. Departure dates for northward migrating waders indicate that the migration window (span over which birds depart) decreases with proximity to the northern breeding grounds. We suggest that migration schedules become tighter as birds get nearer to the breeding grounds. Thus the lack of a relationship between condition and departure date in Great Knots may reflect the fact that the departure episode under study is the first one in sequence and is still 4-8 weeks before breeding.

Samples of great knots (Calidris tenuirostris) were collected in an earlier project before and after a 5420-km migration stage from Australia to China (believed to be flown non-stop) to determine the mass of fat consumed,and also the mass of protein withdrawn from the flight muscles and other organs. The flight was simulated by a "time-marching" computation, which calculated the fuel energy required, and allowed different hypotheses to be tried for the consumption of protein. The simulation predicted that the great knots would take about 4 days to cover the distance, in agreement with field estimates. Realistic predictions of the consumption of fat and protein were obtained by setting the conversion efficiency to 0.23 and the body drag coefficient to 0.10, withdrawing sufficient protein from the flight muscles to keep the specific work in the myofibrils constant throughout the flight, and taking enough additional protein from other tissues to bring the energy derived from oxidising protein to 5% of the total energy consumed. The same computation was applied to published data on the pre-migration body composition of bar-tailed godwits (Limosa lapponica) which are said to migrate over 10 000 km from Alaska to New Zealand. The computed range for a sample killed by collision with an obstruction, while actually departing from Alaska, was sufficient to reach the South Pole. A second sample, shot before departure from New Zealand, would have run out of fat before reaching Alaska, but could easily have reached northern Australia, where these godwits stage on their northbound migration. The higher range estimate for the Alaskan birds was not due to higher fat mass (only 5% difference) but to a higher fat fraction, which they had achieved by reducing the mass of other organs before departure. Some recent observations of high chemical power, observed in wind tunnel experiments, have been interpreted as being due to much lower conversion efficiency than the value of 0.23 assumed here, but this interpretation is flawed. Measurements of mechanical power from another wind tunnel project were also unexpectedly high, suggesting that unsteady flight by wind tunnel birds increases their power requirements, both mechanical and chemical, with no implications for efficiency. The calculated power is for "steady horizontal flight". meaning that a valid test of predicted power requires birds to be trained to hold a constant position in the test section, while maintaining a steady wingbeat frequency and amplitude. This has not been achieved in recent experiments, and is hard to achieve when using physiological methods, because of the long periods of continuous flight needed. Measurements of mechanical rather than chemical power require shorter flight times, and offer better prospects for reliable power measurements.