On September 13 to 15, a series of events of the two-day China Festival, dedicated to celebrate the 70^th anniversary of the founding of the People's Republic ot China and the establishment of China-Russia diploma...On September 13 to 15, a series of events of the two-day China Festival, dedicated to celebrate the 70^th anniversary of the founding of the People's Republic ot China and the establishment of China-Russia diplomatic relations.The China Festival was initiated by the Institute of Far Eastern Studies of the Russian Academy of Sciences and supported by the Embassy of the People's Republic of China in Russia, the Ministry of Culture and Tourism of the People's Republic of China, China Cultural Center in Moscow and other government bodies and organizations from both countries.展开更多
In undertaking regular surveys on those waterbirds appearing on Fujian coast and on offshore islands,people of Xiamen Bird-watching Society had observed,for five times during 2007-2009,three marked individuals of the ...In undertaking regular surveys on those waterbirds appearing on Fujian coast and on offshore islands,people of Xiamen Bird-watching Society had observed,for five times during 2007-2009,three marked individuals of the Roseate Tern (Sterna dougallii) on Caiyu Archipelago of south Fujian offshore; it is now quite certain that the leg-flags were marked on birds by people of the Australasian Wader Studies Group (AWSG) and at least one of those leg-flagged terns is already over six or seven years old by the time of re-sighting; this record might be useful and helpful for further estimating the life circle as well as the length of generation of those gulls and terns appearing and breeding along the SE Chinese coast,such as the Black-tailed Gull (Larus crassirostris),the Great Crested Tern (Sterna bergii),the Chinese Crested Tern (S.bernsteini),etc.展开更多
Understanding the spatiotemporal patterns of animal movement is a central theme in the growing field of movement ecology.The Bridled Tern(Onychoprion anaethetus)is widely distributed across tropical and subtropical la...Understanding the spatiotemporal patterns of animal movement is a central theme in the growing field of movement ecology.The Bridled Tern(Onychoprion anaethetus)is widely distributed across tropical and subtropical latitudes;however,knowledge of its annual movement is based only on relatively scarce recoveries of ringed birds.Studying the annual movement of pelagic seabirds is important to identify the impact of changes of marine habitats on them.We examined fine-scaled movement patterns of the species from two colonies in southern China by using GPS-GSM transmitters in 2018–2022.Twenty-three terns bred in Xichiyu Islet and Qilianyu Islet while wintered in four different sites:Gulf of Thailand,Natuna Islands,The Sulu Sea,and Makassar Strait.Bridled Terns made small detours and employed a fly-and-forage strategy with frequent stopovers to forage during autumn migration,but took more direct routes and reduced the need for stopovers during spring migration.Distance of migration between breeding and winter sites was significantly longer in autumn(average 3635 km)when compared with spring(2777 km).Ten birds with whole-year tracking data used the same breeding sites both years and four birds with tracking data of two consecutive years returned to the same wintering area,indicating that Bridled Terns are highly faithful to their breeding and wintering grounds.展开更多
Background: Water clarity may negatively influence rate of plunge diving and prey capture success of piscivorous plunge-diving birds, and therefore has implications for their conservation in polluted urban wetlands. W...Background: Water clarity may negatively influence rate of plunge diving and prey capture success of piscivorous plunge-diving birds, and therefore has implications for their conservation in polluted urban wetlands. We studied the relationship between water clarity and the abundance and prey capture success of Pied Kingfishers(Ceryle rudis) and Common Terns(Sterna hirundo) in two polluted coastal waters of south-east Ghana—the Weija Lake and Densu Delta Ramsar Site.Methods: On each wetland, data on abundance and prey capture success of plunge-divers were collected in four spatio-temporal quadrats of 100 m × 100 m and analysed with concurrent measurements of water quality parameters using GLM regression with Pearson's correlation coefficients.Results: Mean prey capture success of Pied Kingfishers(34.7 e two species responded differently to water clarity. The± 13.1%) and Common Terns(35.3 abundance of Common Terns was± 11.0%) were similar but th significantly higher in less transparent/more turbid water while that of Pied Kingfishers showed no significant relationship with turbidity and transparency. In contrast, the prey capture success of Common Terns was neither related to transparency nor turbidity, as opposed to that of Pied Kingfishers which was significantly higher in more turbid/less transparent waters. Correlations between capture success and bird abundance, as well as capture attempts were insignificant, suggesting that increased fish abundance associated with cloudy water may not necessarily promote higher abundance and capture success of foraging birds. Thus, when foraging in less transparent water, capture success may depend more on predator avoidance by fish prey than lower prey detectability of foraging birds.Conclusion: Within a gradient of 15–51 cm transparency studied, lower water clarity did not constrain prey capture success of Common Terns and Pied Kingfishers. Further studies on the foraging ecology of plunge-divers in coastal Ghana are however required to make firm conclusions on the relationship between water clarity and foraging birds and fish prey abundances, as well as capture success.展开更多
Background:While nest attentiveness plays a critical role in the reproductive success of avian species,nest attentiveness data with high temporal resolution is not available for many species.However,improvements in bo...Background:While nest attentiveness plays a critical role in the reproductive success of avian species,nest attentiveness data with high temporal resolution is not available for many species.However,improvements in both video monitoring and temperature logging devices present an opportunity to increase our understanding of this aspect of avian behavior.Methods:To investigate nest attentiveness behaviors and evaluate these technologies,we monitored 13 nests across two Common Tern(Sterna hirundo)breeding colonies with a paired video camera-temperature logger approach,while monitoring 63 additional nests with temperature loggers alone.Observations occurred from May to August of 2017 on Poplar(Chesapeake Bay,Maryland,USA)and Skimmer Islands(Isle of Wight Bay,Maryland,USA).We examined data respective to four times of day:Morning(civil dawn‒11:59),Peak(12:00‒16:00),Cooling(16:01‒civil dusk),and Night(civil dusk‒civil dawn).Results:While successful nests had mostly short duration off-bouts and maintained consistent nest attentiveness throughout the day,failed nests had dramatic reductions in nest attentiveness during the Cooling and Night periods(p<0.05)with one colony experiencing repeated nocturnal abandonment due to predation pressure from a Great Horned Owl(Bubo virginianus).Incubation appeared to ameliorate ambient temperatures during Night,as nests were significantly warmer during Night when birds were on versus off the nest(p<0.05).Meanwhile,off-bouts during the Peak period occurred during higher ambient temperatures,perhaps due to adults leaving the nest during the hottest periods to perform belly soaking.Unfortunately,temperature logger data alone had limited ability to predict nest attentiveness status during shorter bouts,with results highly dependent on time of day and bout duration.While our methods did not affect hatching success(p>0.05),video-monitored nests did have significantly lower clutch sizes(p<0.05).Conclusions:The paired use of iButtons and video cameras enabled a detailed description of the incubation behavior of COTE.However,while promising for future research,the logistical and potential biological complications involved in the use of these methods suggest that careful planning is needed before these devices are utilized to ensure data is collected in a safe and successful manner.展开更多
A pair of Black Oystercatchers(Haematopus bachmani)established a nest in June 2022 at“Tern Town”,an island located in Hayward,California along the eastern side of the San Francisco Bay.This is the first documented o...A pair of Black Oystercatchers(Haematopus bachmani)established a nest in June 2022 at“Tern Town”,an island located in Hayward,California along the eastern side of the San Francisco Bay.This is the first documented occurrence of oystercatchers successfully nesting and fledgling young in association with California Least Terns.The island provides nesting habitat for three special status species.Since 2015,and for a total of six breeding seasons,the endangered California Least Tern(Sternula antillarum browni),the threatened Western Snowy Plover(Charadrius alexandrinus nivosus)and species-of-special-concern Black Skimmer(Rynchops niger),have nested successfully,in association with American Avocet(Recurvirostra americana)and Black-necked Stilt(Himantopus mexicanus).We collected shells near the oystercatcher nest to assess their diet.Diet data showed the oystercatchers foraged on,in decreasing order of abundance,Japanese Little-necked Clams(Ruditapes philippinarum),Ribbed Mussels(Geukensia demissa),Bent-nose Clams(Macoma nasuta),Limpets(Patellogastropoda sp.)and Bay Mussels(Mytilus edulis).This new report on breeding Black Oystercatchers indicates that managing habitat for California Least Tern,Western Snowy Plover,and Black Skimmer can also benefit Black Oystercatcher.This site-specific information on breeding Black Oystercatchers supports recovery plan tasks that are consistent with managing habitat for California Least Tern,Western Snowy Plover and Black Skimmer.展开更多
Most behavioral traits are known to be weakly heritable,possibly due to their extreme complexity and flexibility.Despite this general pattern,within-species variation in avian colony size choice has been reported to h...Most behavioral traits are known to be weakly heritable,possibly due to their extreme complexity and flexibility.Despite this general pattern,within-species variation in avian colony size choice has been reported to have a strong additive genetic component,but we are aware of no attempts to assess the heritability of avian sociality at the finer spatial scale.Here,we used an animal model and parent-offspring regression to quantify additive genetic variance in social phenotype(local nesting density)in a nonpasserine waterbird,the common tern Sterna hirundo.For this purpose,we used a novel experimental framework,where variation in the social environment was generated by providing birds with artificial patches of attractive nesting substrate that markedly varied in size.During 2011-2019,we collected data on social preferences for either low or high nesting density in over 250 individuals,either kin(mostly parent-offspring relationships)or non-kin recorded breeding multiple times across years.All heritability estimates of local nesting density were low(<0.10),irrespectively of fixed effects(sex and year)included in the models,data used in the modeling(all individuals vs.early recruits),or methodological approach(animal model vs.parent-offspring regression).We conclude that avian sociality,as measured at the local scale,may be much less heritable than colony size choice,as measured at the landscape level.Our study adds to the understanding of additive genetic variance in avian behavior,and it underlines a scale dependency in the heritability of behavioral traits.展开更多
Seabirds are valuable indicators of marine ecosystem processes and studying seabird diets can shed light on natural or human-induced variability in food-web composition.Specifically single-prey loading seabird species...Seabirds are valuable indicators of marine ecosystem processes and studying seabird diets can shed light on natural or human-induced variability in food-web composition.Specifically single-prey loading seabird species such as terns have the potential to act as visual sentinels of prey availability offshore.However,obtaining diet information from remote bird colonies is often challenging and time consuming.In this pilot study we present a novel approach to combine two established methods to study seabird foraging ecology,providing a powerful and cost-effective tool to study the distribution of prey items available to seabirds.We combined GPS tracking data of Sandwich Terns(Thalasseus sandvicensis)with prey-observations from a hide in 2012 and 2013,and from semicontinuously recorded camera footage in 2017.By doing so,we identified 115 approximate catch locations of prey(86 herring/sprat Clupeidae,29 sandeel Ammodytidae).Combining GPS-data and prey observations yielded detailed knowledge on the movements and chick diets of tracked birds as well as the spatial origin and lengths of captured prey items.Further catch distances of both Clupeidae and Ammodytidae resulted in deliveries of larger prey items and thus higher energy yield per trip,but also a higher energy expenditure per trip.We discuss the limitations and potential of our methodological approach to study foraging energetics during chick-provisioning of seabirds that carry prey items visible in their beaks.展开更多
Climate change has advanced the phenology of many organisms. Migratory animals face particular problems because climate change in the breeding and the wintering range may be asynchronous, preventing rapid response to ...Climate change has advanced the phenology of many organisms. Migratory animals face particular problems because climate change in the breeding and the wintering range may be asynchronous, preventing rapid response to changing conditions. Advancement in timing of spring migration may have carry-over effects to other parts of the annual cycle, simply because advancement of one event in the annual cycle also advances subsequent events, gradually causing a general shift in the timing of the entire annual cycle. Such a phenotypic shift could generate accumulating effects over the years for individuals, but also across generations. Here we test this novel hypothesis of phenotypic response to climate change by using long-term data on the Arctic tern Sterna paradisaea. Mean breeding date advanced by almost three weeks during the last 70 years. Annual arrival date at the breeding grounds during a period of 47 years was predicted by environmental conditions in the winter quarters in the Southern Ocean near the Antarctic and by mean breeding date the previous year. Annual mean breeding date was only marginally determined by timing of arrival the current year, but to a larger extent by arrival date and breeding date the previous year. Learning affected arrival date as shown by a positive correlation between arrival date in year （i ＋ 1） relative to breeding date in year （i） and the selective advantage of early breeding in year （i）. This provides a mechanism for changes in arrival date being adjusted to changing environmental conditions. This study suggests that adaptation to changing climatic conditions can be achieved through learning from year to year展开更多
Three Chinese Crested Terns (Sterna bernsteini) were seen stopping at the Golden Coast of Rizhao (city), southern Shandong Province, China, on 6 September 2011. This is the third record of the bird appearing in northern
The global climatic change study is a hot point today.As the pattern of the general circulation of the atmosphere is the key factor for climate,the reconstruction of the pattern of the past general circulation of the ...The global climatic change study is a hot point today.As the pattern of the general circulation of the atmosphere is the key factor for climate,the reconstruction of the pattern of the past general circulation of the atmosphere has become important part of the global climatic change study.The paleowind belts are the comprising part of the past general circulation of the atmosphere and also the records of the circulation,therefore,their reconstruction will be helpful to the reconstruction of the general circulation of the atmosphere.In present years,the pattern of the general circulation of the atmosphere has attracted great concern from scientists.For example,Zhang Linyuan and Liu Dongsheng, based on the existence and inexistence of the Tibetan Plateau and paleogeography,divide the evolution of the general circulation of the atmosphere in eastern asia into two stages:the planetary wind stage before the uplift of the plateau and the monsoon stage after the uplift of the plateau which is subdivided into ancient monsoon and modern monsoon stages.While Dong Guangrong et al., Jiang Xinsheng et al. and Cooke et al, based on the latitudinal distribution of the Cretaceous and Tertiary deserts and the generation of arid climate,suggest that there was a subtropical high pressure zone across the eastern asia and was a planetary wind system,but have not found any direct record of the circulation.It is true that before the Early Tertiary,not only organism, but also inorganism,i.e.,biogeography and lithogeography, show strong zonal distribution.It can only indicate that zonal climate was evident at that time.Of course, as the climate is the result of the influences on the ground by zones of the circulation,it is reasonable to deduce the existence of zonal circulation,i.e. the the existence of the planetary wind system,from the zonal climate.But it would be much better if direct record of planetary wind system were found.Prevailing winds are the main geological agent for a desert which must leave deep stamps on the desert.The stamps on modern desert are reflected by dune migrating directions and on paleodesert by foreset dip directions..It is the most direct geological record for reconstructing paleowind belts and has been extensively used to reconstruct paleowind belts,paleogeography,paleoclimate and even to check the paleolatitude determined by paleomagnetism (for example, Opdyke and Runcorn, 1960; Creer, 1958; Pook, 1962; Bigarella and Salamuni,1961).展开更多
The application of very large floating structure (VLFS) to the utilization of ocean space and exploitation of ocean resources has become one of the issues of great interest in international ocean engineering field. Ow...The application of very large floating structure (VLFS) to the utilization of ocean space and exploitation of ocean resources has become one of the issues of great interest in international ocean engineering field. Owing to the advantage of simplicity in structure and low cost of construction and maintenance, box-type VLFS can be used in the calm water area near the coast as the structure configuration of floating airport. In this paper, a 3D linear hydroelastic theory is used to study the dynamic response of box-type VLFS in sinusoidal regular waves. A beam model and a 3D FEM model are respectively employed to describe the dynamic characteristics of the box-type Structure in vacuum. A hydrodynamic model (3D potential theory of flexible body) is applied to investigate the effect of different dry models on the hydroelastic response of box-type structure. Based on the calculation of hydroelastic response in regular waves, the rigid body motion displacement, flexible deflection, and the short term and long term wave induced bending moments are also predicted.展开更多
In this paper, we study the threshold result for the initial boundary value problem of non-homogeneous semilinear parabolic equations {μt-△μ=g（μ）＋λf（x）,（x,t）∈Ω×（0,T）,μ=0,（x,t）∈ Ω×[0,T）...In this paper, we study the threshold result for the initial boundary value problem of non-homogeneous semilinear parabolic equations {μt-△μ=g（μ）＋λf（x）,（x,t）∈Ω×（0,T）,μ=0,（x,t）∈ Ω×[0,T）,μ（x,0）=μ0（x）≥0,x∈Ω.By combining a priori estimate of global solution with property of stationary solution set of problem （P）, we prove that the minimal stationary solution Uλ（x） of problem （P） is stable, whereas, any other stationary solution is an initial datum threshold for the existence and nonexistence of global solution to problem （P）.展开更多
Micro-/nanocrystalline diamond films deposited in Ar/H2/CH4 microwave plasmas have been studied, with argon flow rates in the range of 70-100 sccm. The effects of argon addition on morphology, surface roughness, quali...Micro-/nanocrystalline diamond films deposited in Ar/H2/CH4 microwave plasmas have been studied, with argon flow rates in the range of 70-100 sccm. The effects of argon addition on morphology, surface roughness, quality and structure were investigated by scanning electron microscopy, surface profiler, Raman spectrometer and X-ray diffraction （XRD）. It is demonstrated that when the argon flow rate is 70 sccm or 75 sccm, well-faceted polycrystalline diamond films can be grown at a low substrate temperature less than 610 ~C. With the increase in the argon flow rate, the smooth crystallographic planes disappear gradually. Instead, rough crystallographic planes made up of small aggregates begin to take shape, resulting from the increase in the secondary nucleation rate. Nanocrystalline diamond films were obtained at a flow rate of 100 sccm, and all of the prepared diamond films were smooth, with a surface roughness （Ra） less than 20 nm. Raman analyses reveal that the amount of amorphous carbon increases significantly with the increase in argon flow. The results of XRD show that crystalline size and preferential orientation of diamond films depend on the argon content in the plasmas.展开更多
When evaluating the track fusion algorithm,common accuracy indexes may fail to evaluate the fusion accuracy correctly when the state estimation and the real target cannot be one-to-one,and fail to effectively distingu...When evaluating the track fusion algorithm,common accuracy indexes may fail to evaluate the fusion accuracy correctly when the state estimation and the real target cannot be one-to-one,and fail to effectively distinguish the performance of the algorithm when the state estimation is similar.Therefore,it is necessary to construct a high-resolution evaluation index,which can evaluate the track fusion algorithm more accurately,reasonably and comprehensively.Firstly,the advant ages and disadvantages of the optimal subpattern assignment(OSPA)dis tance as the accuracy index to evaluate the track fusion algorithm are analyzed.Then,its deficiencies are improved by using the Hellinger distance instead of the original Euclidean distance,and the distance is index transformed.Finally,a new evaluation index for track fusion algorithms is proposed,which is the OSPA distance based on Hellinger distance and index transformation.The simulation results show that the new index can not only correctly evaluate the fusion precision,but also consider the state uncertainty,making that can evaluate the track fusion algorithm more sensitively,and effectively solves the sensitivity of the index to the cut-off parameter c through index transformation.展开更多
Background:The extent to which pairs remain together during the annual cycle is a key question in the behav-ioural ecology of migratory birds.While a few species migrate and winter as family units,for most the extent ...Background:The extent to which pairs remain together during the annual cycle is a key question in the behav-ioural ecology of migratory birds.While a few species migrate and winter as family units,for most the extent to which breeding partners associate in the non-breeding season is unknown.The Arctic Tern(Sterna paradisaea)has one of the longest migrations of any species,and the aim of this study was to establish whether or not partners remain together after breeding.Methods:Leg-mounted geolocators were fitted to breeding pairs of Arctic Terns nesting on the Farne Islands,North-umberland,UK.The devices were recovered for analysis the following year.Results:Analysis of data for the six pairs which returned the following year showed that partners departed from the colony at different times after breeding and migrated independently to different Antarctic regions.Partners also departed from the Antarctic and turned to the breeding colony independently.One third of the pairs divorced on return.Conclusions:For long-distance migrants reliant on unpredictable foraging opportunities,it may not be viable to remain as pairs away from the breeding colony.Synchrony in arrival times at the breeding colony may maximise the chance of retaining a familiar partner,but could be affected by environmental factors in wintering areas or along migration routes.展开更多
In this paper,a hybrid model based on sooty tern optimization algo-rithm(STOA)is proposed to optimize the parameters of the support vector machine(SVM)and identify the best feature sets simultaneously.Feature selec-ti...In this paper,a hybrid model based on sooty tern optimization algo-rithm(STOA)is proposed to optimize the parameters of the support vector machine(SVM)and identify the best feature sets simultaneously.Feature selec-tion is an essential process of data preprocessing,and it aims to find the most rele-vant subset of features.In recent years,it has been applied in many practical domains of intelligent systems.The application of SVM in many fields has proved its effectiveness in classification tasks of various types.Its performance is mainly determined by the kernel type and its parameters.One of the most challenging process in machine learning is feature selection,intending to select effective and representative features.The main disadvantages of feature selection processes included in classical optimization algorithm are local optimal stagnation and slow convergence.Therefore,the hybrid model proposed in this paper merges the STOA and differential evolution(DE)to improve the search efficiency and con-vergence rate.A series of experiments are conducted on 12 datasets from the UCI repository to comprehensively and objectively evaluate the performance of the proposed method.The superiority of the proposed method is illustrated from dif-ferent aspects,such as the classification accuracy,convergence performance,reduced feature dimensionality,standard deviation(STD),and computation time.展开更多
We analyze morphometrics from a sample of 276 White-winged Black Tern(Chlidonias leucopterus) caught in north-west Australia on 4 March 2011. An estimated 40000 terns were present — the largest concentration of this ...We analyze morphometrics from a sample of 276 White-winged Black Tern(Chlidonias leucopterus) caught in north-west Australia on 4 March 2011. An estimated 40000 terns were present — the largest concentration of this species yet reported from Australia. When comparing juveniles with adults, only wing length and body mass differed significantly; however, juveniles were still easily recognized by plumage and wing molt as late as March. There was little evidence of any dramatic weight gain in adults before their northward migration. No morphological characteristic distinguishing sex was found. We confirmed that terns caught in this study did not appear to differ morphologically from those of the western palearctic populations. We describe wing molt based on data from 354 individuals captured and banded in Australia over 28 years. Wing molt proceeds in much the same way as found in other small terns.展开更多
The California least tern （Sternula antillarum browni） is an endangered species. The two largest colonies of this bird species in the San Francisco Bay, California, USA, are located 23 km apart at Alameda Point and ...The California least tern （Sternula antillarum browni） is an endangered species. The two largest colonies of this bird species in the San Francisco Bay, California, USA, are located 23 km apart at Alameda Point and Hayward Regional Shoreline. The Alameda Point colony, on the former Naval Air Station, Alameda, has grown at an average rate of 9.2% per year since its discovery in 1976 and has a nesting density ranging from 1-153 nests per ha. Long-term breeding success at Alameda has averaged 0.86 fledglings per breeding pair. Least tems began appearing in 2003, at an island in Hayward enhanced with substrate mediums and social attraction devices. Successful breeding attempts have been observed at the Hayward colony since 2006. The Hayward colony has grown at an average rate of 51.5% per year, has a nesting density ranging from 33-333 nests per ha and long-term breeding success average of 0.87 fledglings per breeding pair. Dropped fish have been collected from both colonies, and silversides （family Atherinopsidae） are the dominant prey. Alameda terns forage on a greater variety of species than the Hayward terns. The regression results indicate the importance of Northern anchovy （Engraulis mordax） to the breeding success of the Alameda colony.展开更多
文摘On September 13 to 15, a series of events of the two-day China Festival, dedicated to celebrate the 70^th anniversary of the founding of the People's Republic ot China and the establishment of China-Russia diplomatic relations.The China Festival was initiated by the Institute of Far Eastern Studies of the Russian Academy of Sciences and supported by the Embassy of the People's Republic of China in Russia, the Ministry of Culture and Tourism of the People's Republic of China, China Cultural Center in Moscow and other government bodies and organizations from both countries.
文摘In undertaking regular surveys on those waterbirds appearing on Fujian coast and on offshore islands,people of Xiamen Bird-watching Society had observed,for five times during 2007-2009,three marked individuals of the Roseate Tern (Sterna dougallii) on Caiyu Archipelago of south Fujian offshore; it is now quite certain that the leg-flags were marked on birds by people of the Australasian Wader Studies Group (AWSG) and at least one of those leg-flagged terns is already over six or seven years old by the time of re-sighting; this record might be useful and helpful for further estimating the life circle as well as the length of generation of those gulls and terns appearing and breeding along the SE Chinese coast,such as the Black-tailed Gull (Larus crassirostris),the Great Crested Tern (Sterna bergii),the Chinese Crested Tern (S.bernsteini),etc.
基金the National Natural Science Foundation of China(No.31727901)the National Key Research and Development Program of China(2022YFC2601600).
文摘Understanding the spatiotemporal patterns of animal movement is a central theme in the growing field of movement ecology.The Bridled Tern(Onychoprion anaethetus)is widely distributed across tropical and subtropical latitudes;however,knowledge of its annual movement is based only on relatively scarce recoveries of ringed birds.Studying the annual movement of pelagic seabirds is important to identify the impact of changes of marine habitats on them.We examined fine-scaled movement patterns of the species from two colonies in southern China by using GPS-GSM transmitters in 2018–2022.Twenty-three terns bred in Xichiyu Islet and Qilianyu Islet while wintered in four different sites:Gulf of Thailand,Natuna Islands,The Sulu Sea,and Makassar Strait.Bridled Terns made small detours and employed a fly-and-forage strategy with frequent stopovers to forage during autumn migration,but took more direct routes and reduced the need for stopovers during spring migration.Distance of migration between breeding and winter sites was significantly longer in autumn(average 3635 km)when compared with spring(2777 km).Ten birds with whole-year tracking data used the same breeding sites both years and four birds with tracking data of two consecutive years returned to the same wintering area,indicating that Bridled Terns are highly faithful to their breeding and wintering grounds.
文摘Background: Water clarity may negatively influence rate of plunge diving and prey capture success of piscivorous plunge-diving birds, and therefore has implications for their conservation in polluted urban wetlands. We studied the relationship between water clarity and the abundance and prey capture success of Pied Kingfishers(Ceryle rudis) and Common Terns(Sterna hirundo) in two polluted coastal waters of south-east Ghana—the Weija Lake and Densu Delta Ramsar Site.Methods: On each wetland, data on abundance and prey capture success of plunge-divers were collected in four spatio-temporal quadrats of 100 m × 100 m and analysed with concurrent measurements of water quality parameters using GLM regression with Pearson's correlation coefficients.Results: Mean prey capture success of Pied Kingfishers(34.7 e two species responded differently to water clarity. The± 13.1%) and Common Terns(35.3 abundance of Common Terns was± 11.0%) were similar but th significantly higher in less transparent/more turbid water while that of Pied Kingfishers showed no significant relationship with turbidity and transparency. In contrast, the prey capture success of Common Terns was neither related to transparency nor turbidity, as opposed to that of Pied Kingfishers which was significantly higher in more turbid/less transparent waters. Correlations between capture success and bird abundance, as well as capture attempts were insignificant, suggesting that increased fish abundance associated with cloudy water may not necessarily promote higher abundance and capture success of foraging birds. Thus, when foraging in less transparent water, capture success may depend more on predator avoidance by fish prey than lower prey detectability of foraging birds.Conclusion: Within a gradient of 15–51 cm transparency studied, lower water clarity did not constrain prey capture success of Common Terns and Pied Kingfishers. Further studies on the foraging ecology of plunge-divers in coastal Ghana are however required to make firm conclusions on the relationship between water clarity and foraging birds and fish prey abundances, as well as capture success.
基金This work was supported by the U.S.Army Corps of Engineers(Baltimore District),U.S.Geological Survey(Patuxent Wildlife Research Center)the University of Maryland,the Maryland Department of Natural Resources(Wildlife and Heritage Program)the Maryland Environmental Service,and the Maryland Coastal Bays Program.
文摘Background:While nest attentiveness plays a critical role in the reproductive success of avian species,nest attentiveness data with high temporal resolution is not available for many species.However,improvements in both video monitoring and temperature logging devices present an opportunity to increase our understanding of this aspect of avian behavior.Methods:To investigate nest attentiveness behaviors and evaluate these technologies,we monitored 13 nests across two Common Tern(Sterna hirundo)breeding colonies with a paired video camera-temperature logger approach,while monitoring 63 additional nests with temperature loggers alone.Observations occurred from May to August of 2017 on Poplar(Chesapeake Bay,Maryland,USA)and Skimmer Islands(Isle of Wight Bay,Maryland,USA).We examined data respective to four times of day:Morning(civil dawn‒11:59),Peak(12:00‒16:00),Cooling(16:01‒civil dusk),and Night(civil dusk‒civil dawn).Results:While successful nests had mostly short duration off-bouts and maintained consistent nest attentiveness throughout the day,failed nests had dramatic reductions in nest attentiveness during the Cooling and Night periods(p<0.05)with one colony experiencing repeated nocturnal abandonment due to predation pressure from a Great Horned Owl(Bubo virginianus).Incubation appeared to ameliorate ambient temperatures during Night,as nests were significantly warmer during Night when birds were on versus off the nest(p<0.05).Meanwhile,off-bouts during the Peak period occurred during higher ambient temperatures,perhaps due to adults leaving the nest during the hottest periods to perform belly soaking.Unfortunately,temperature logger data alone had limited ability to predict nest attentiveness status during shorter bouts,with results highly dependent on time of day and bout duration.While our methods did not affect hatching success(p>0.05),video-monitored nests did have significantly lower clutch sizes(p<0.05).Conclusions:The paired use of iButtons and video cameras enabled a detailed description of the incubation behavior of COTE.However,while promising for future research,the logistical and potential biological complications involved in the use of these methods suggest that careful planning is needed before these devices are utilized to ensure data is collected in a safe and successful manner.
文摘A pair of Black Oystercatchers(Haematopus bachmani)established a nest in June 2022 at“Tern Town”,an island located in Hayward,California along the eastern side of the San Francisco Bay.This is the first documented occurrence of oystercatchers successfully nesting and fledgling young in association with California Least Terns.The island provides nesting habitat for three special status species.Since 2015,and for a total of six breeding seasons,the endangered California Least Tern(Sternula antillarum browni),the threatened Western Snowy Plover(Charadrius alexandrinus nivosus)and species-of-special-concern Black Skimmer(Rynchops niger),have nested successfully,in association with American Avocet(Recurvirostra americana)and Black-necked Stilt(Himantopus mexicanus).We collected shells near the oystercatcher nest to assess their diet.Diet data showed the oystercatchers foraged on,in decreasing order of abundance,Japanese Little-necked Clams(Ruditapes philippinarum),Ribbed Mussels(Geukensia demissa),Bent-nose Clams(Macoma nasuta),Limpets(Patellogastropoda sp.)and Bay Mussels(Mytilus edulis).This new report on breeding Black Oystercatchers indicates that managing habitat for California Least Tern,Western Snowy Plover,and Black Skimmer can also benefit Black Oystercatcher.This site-specific information on breeding Black Oystercatchers supports recovery plan tasks that are consistent with managing habitat for California Least Tern,Western Snowy Plover and Black Skimmer.
基金supported by the research grant of the National Science Centre in Poland(2016/23/B/NZ8/02374).
文摘Most behavioral traits are known to be weakly heritable,possibly due to their extreme complexity and flexibility.Despite this general pattern,within-species variation in avian colony size choice has been reported to have a strong additive genetic component,but we are aware of no attempts to assess the heritability of avian sociality at the finer spatial scale.Here,we used an animal model and parent-offspring regression to quantify additive genetic variance in social phenotype(local nesting density)in a nonpasserine waterbird,the common tern Sterna hirundo.For this purpose,we used a novel experimental framework,where variation in the social environment was generated by providing birds with artificial patches of attractive nesting substrate that markedly varied in size.During 2011-2019,we collected data on social preferences for either low or high nesting density in over 250 individuals,either kin(mostly parent-offspring relationships)or non-kin recorded breeding multiple times across years.All heritability estimates of local nesting density were low(<0.10),irrespectively of fixed effects(sex and year)included in the models,data used in the modeling(all individuals vs.early recruits),or methodological approach(animal model vs.parent-offspring regression).We conclude that avian sociality,as measured at the local scale,may be much less heritable than colony size choice,as measured at the landscape level.Our study adds to the understanding of additive genetic variance in avian behavior,and it underlines a scale dependency in the heritability of behavioral traits.
文摘Seabirds are valuable indicators of marine ecosystem processes and studying seabird diets can shed light on natural or human-induced variability in food-web composition.Specifically single-prey loading seabird species such as terns have the potential to act as visual sentinels of prey availability offshore.However,obtaining diet information from remote bird colonies is often challenging and time consuming.In this pilot study we present a novel approach to combine two established methods to study seabird foraging ecology,providing a powerful and cost-effective tool to study the distribution of prey items available to seabirds.We combined GPS tracking data of Sandwich Terns(Thalasseus sandvicensis)with prey-observations from a hide in 2012 and 2013,and from semicontinuously recorded camera footage in 2017.By doing so,we identified 115 approximate catch locations of prey(86 herring/sprat Clupeidae,29 sandeel Ammodytidae).Combining GPS-data and prey observations yielded detailed knowledge on the movements and chick diets of tracked birds as well as the spatial origin and lengths of captured prey items.Further catch distances of both Clupeidae and Ammodytidae resulted in deliveries of larger prey items and thus higher energy yield per trip,but also a higher energy expenditure per trip.We discuss the limitations and potential of our methodological approach to study foraging energetics during chick-provisioning of seabirds that carry prey items visible in their beaks.
基金Funds for Nature (WWF-) China Programme’s Small Grand for Species for their successive support on our field survey in 2004 (RSPB),from May 2005 to September 2006 (WWF-China),and then from September 2007 to October 2008 (RSPB),respectively
文摘The Chinese Crested Tern (Sterna bernsteini;hereafter regarded as CCT, Plate I) is perhaps the most enigmatic tern bird in the world–though
文摘Climate change has advanced the phenology of many organisms. Migratory animals face particular problems because climate change in the breeding and the wintering range may be asynchronous, preventing rapid response to changing conditions. Advancement in timing of spring migration may have carry-over effects to other parts of the annual cycle, simply because advancement of one event in the annual cycle also advances subsequent events, gradually causing a general shift in the timing of the entire annual cycle. Such a phenotypic shift could generate accumulating effects over the years for individuals, but also across generations. Here we test this novel hypothesis of phenotypic response to climate change by using long-term data on the Arctic tern Sterna paradisaea. Mean breeding date advanced by almost three weeks during the last 70 years. Annual arrival date at the breeding grounds during a period of 47 years was predicted by environmental conditions in the winter quarters in the Southern Ocean near the Antarctic and by mean breeding date the previous year. Annual mean breeding date was only marginally determined by timing of arrival the current year, but to a larger extent by arrival date and breeding date the previous year. Learning affected arrival date as shown by a positive correlation between arrival date in year （i ＋ 1） relative to breeding date in year （i） and the selective advantage of early breeding in year （i）. This provides a mechanism for changes in arrival date being adjusted to changing environmental conditions. This study suggests that adaptation to changing climatic conditions can be achieved through learning from year to year
文摘Three Chinese Crested Terns (Sterna bernsteini) were seen stopping at the Golden Coast of Rizhao (city), southern Shandong Province, China, on 6 September 2011. This is the third record of the bird appearing in northern
文摘The global climatic change study is a hot point today.As the pattern of the general circulation of the atmosphere is the key factor for climate,the reconstruction of the pattern of the past general circulation of the atmosphere has become important part of the global climatic change study.The paleowind belts are the comprising part of the past general circulation of the atmosphere and also the records of the circulation,therefore,their reconstruction will be helpful to the reconstruction of the general circulation of the atmosphere.In present years,the pattern of the general circulation of the atmosphere has attracted great concern from scientists.For example,Zhang Linyuan and Liu Dongsheng, based on the existence and inexistence of the Tibetan Plateau and paleogeography,divide the evolution of the general circulation of the atmosphere in eastern asia into two stages:the planetary wind stage before the uplift of the plateau and the monsoon stage after the uplift of the plateau which is subdivided into ancient monsoon and modern monsoon stages.While Dong Guangrong et al., Jiang Xinsheng et al. and Cooke et al, based on the latitudinal distribution of the Cretaceous and Tertiary deserts and the generation of arid climate,suggest that there was a subtropical high pressure zone across the eastern asia and was a planetary wind system,but have not found any direct record of the circulation.It is true that before the Early Tertiary,not only organism, but also inorganism,i.e.,biogeography and lithogeography, show strong zonal distribution.It can only indicate that zonal climate was evident at that time.Of course, as the climate is the result of the influences on the ground by zones of the circulation,it is reasonable to deduce the existence of zonal circulation,i.e. the the existence of the planetary wind system,from the zonal climate.But it would be much better if direct record of planetary wind system were found.Prevailing winds are the main geological agent for a desert which must leave deep stamps on the desert.The stamps on modern desert are reflected by dune migrating directions and on paleodesert by foreset dip directions..It is the most direct geological record for reconstructing paleowind belts and has been extensively used to reconstruct paleowind belts,paleogeography,paleoclimate and even to check the paleolatitude determined by paleomagnetism (for example, Opdyke and Runcorn, 1960; Creer, 1958; Pook, 1962; Bigarella and Salamuni,1961).
基金This work was financially supported by the National Natural Science Foundation of China (Grant No. 50039010)
文摘The application of very large floating structure (VLFS) to the utilization of ocean space and exploitation of ocean resources has become one of the issues of great interest in international ocean engineering field. Owing to the advantage of simplicity in structure and low cost of construction and maintenance, box-type VLFS can be used in the calm water area near the coast as the structure configuration of floating airport. In this paper, a 3D linear hydroelastic theory is used to study the dynamic response of box-type VLFS in sinusoidal regular waves. A beam model and a 3D FEM model are respectively employed to describe the dynamic characteristics of the box-type Structure in vacuum. A hydrodynamic model (3D potential theory of flexible body) is applied to investigate the effect of different dry models on the hydroelastic response of box-type structure. Based on the calculation of hydroelastic response in regular waves, the rigid body motion displacement, flexible deflection, and the short term and long term wave induced bending moments are also predicted.
基金supported by Natural Science Foundation of China(10971061)Hunan Provincial Innovation Foundation For Postgraduate(CX2010B209)
文摘In this paper, we study the threshold result for the initial boundary value problem of non-homogeneous semilinear parabolic equations {μt-△μ=g（μ）＋λf（x）,（x,t）∈Ω×（0,T）,μ=0,（x,t）∈ Ω×[0,T）,μ（x,0）=μ0（x）≥0,x∈Ω.By combining a priori estimate of global solution with property of stationary solution set of problem （P）, we prove that the minimal stationary solution Uλ（x） of problem （P） is stable, whereas, any other stationary solution is an initial datum threshold for the existence and nonexistence of global solution to problem （P）.
基金supported by National Natural Science Foundation of China(No.11175137)
文摘Micro-/nanocrystalline diamond films deposited in Ar/H2/CH4 microwave plasmas have been studied, with argon flow rates in the range of 70-100 sccm. The effects of argon addition on morphology, surface roughness, quality and structure were investigated by scanning electron microscopy, surface profiler, Raman spectrometer and X-ray diffraction （XRD）. It is demonstrated that when the argon flow rate is 70 sccm or 75 sccm, well-faceted polycrystalline diamond films can be grown at a low substrate temperature less than 610 ~C. With the increase in the argon flow rate, the smooth crystallographic planes disappear gradually. Instead, rough crystallographic planes made up of small aggregates begin to take shape, resulting from the increase in the secondary nucleation rate. Nanocrystalline diamond films were obtained at a flow rate of 100 sccm, and all of the prepared diamond films were smooth, with a surface roughness （Ra） less than 20 nm. Raman analyses reveal that the amount of amorphous carbon increases significantly with the increase in argon flow. The results of XRD show that crystalline size and preferential orientation of diamond films depend on the argon content in the plasmas.
基金the Natural Science Foundation of Hebei Province(No.F2017506006)。
文摘When evaluating the track fusion algorithm,common accuracy indexes may fail to evaluate the fusion accuracy correctly when the state estimation and the real target cannot be one-to-one,and fail to effectively distinguish the performance of the algorithm when the state estimation is similar.Therefore,it is necessary to construct a high-resolution evaluation index,which can evaluate the track fusion algorithm more accurately,reasonably and comprehensively.Firstly,the advant ages and disadvantages of the optimal subpattern assignment(OSPA)dis tance as the accuracy index to evaluate the track fusion algorithm are analyzed.Then,its deficiencies are improved by using the Hellinger distance instead of the original Euclidean distance,and the distance is index transformed.Finally,a new evaluation index for track fusion algorithms is proposed,which is the OSPA distance based on Hellinger distance and index transformation.The simulation results show that the new index can not only correctly evaluate the fusion precision,but also consider the state uncertainty,making that can evaluate the track fusion algorithm more sensitively,and effectively solves the sensitivity of the index to the cut-off parameter c through index transformation.
基金supported by the Natural History Society of Northumbria and the Seabird Group.
文摘Background:The extent to which pairs remain together during the annual cycle is a key question in the behav-ioural ecology of migratory birds.While a few species migrate and winter as family units,for most the extent to which breeding partners associate in the non-breeding season is unknown.The Arctic Tern(Sterna paradisaea)has one of the longest migrations of any species,and the aim of this study was to establish whether or not partners remain together after breeding.Methods:Leg-mounted geolocators were fitted to breeding pairs of Arctic Terns nesting on the Farne Islands,North-umberland,UK.The devices were recovered for analysis the following year.Results:Analysis of data for the six pairs which returned the following year showed that partners departed from the colony at different times after breeding and migrated independently to different Antarctic regions.Partners also departed from the Antarctic and turned to the breeding colony independently.One third of the pairs divorced on return.Conclusions:For long-distance migrants reliant on unpredictable foraging opportunities,it may not be viable to remain as pairs away from the breeding colony.Synchrony in arrival times at the breeding colony may maximise the chance of retaining a familiar partner,but could be affected by environmental factors in wintering areas or along migration routes.
基金Sanming University introduces high-level talents to start scientific research funding support project(20YG14,20YG01)Guiding science and technology projects in Sanming City(2020-G-61,2020-S-39)+1 种基金Educational research projects of young and middle-aged teachers in Fujian Province(JAT200618,JAT200638)Scientific research and development fund of Sanming University(B202009,B202029).
文摘In this paper,a hybrid model based on sooty tern optimization algo-rithm(STOA)is proposed to optimize the parameters of the support vector machine(SVM)and identify the best feature sets simultaneously.Feature selec-tion is an essential process of data preprocessing,and it aims to find the most rele-vant subset of features.In recent years,it has been applied in many practical domains of intelligent systems.The application of SVM in many fields has proved its effectiveness in classification tasks of various types.Its performance is mainly determined by the kernel type and its parameters.One of the most challenging process in machine learning is feature selection,intending to select effective and representative features.The main disadvantages of feature selection processes included in classical optimization algorithm are local optimal stagnation and slow convergence.Therefore,the hybrid model proposed in this paper merges the STOA and differential evolution(DE)to improve the search efficiency and con-vergence rate.A series of experiments are conducted on 12 datasets from the UCI repository to comprehensively and objectively evaluate the performance of the proposed method.The superiority of the proposed method is illustrated from dif-ferent aspects,such as the classification accuracy,convergence performance,reduced feature dimensionality,standard deviation(STD),and computation time.
文摘We analyze morphometrics from a sample of 276 White-winged Black Tern(Chlidonias leucopterus) caught in north-west Australia on 4 March 2011. An estimated 40000 terns were present — the largest concentration of this species yet reported from Australia. When comparing juveniles with adults, only wing length and body mass differed significantly; however, juveniles were still easily recognized by plumage and wing molt as late as March. There was little evidence of any dramatic weight gain in adults before their northward migration. No morphological characteristic distinguishing sex was found. We confirmed that terns caught in this study did not appear to differ morphologically from those of the western palearctic populations. We describe wing molt based on data from 354 individuals captured and banded in Australia over 28 years. Wing molt proceeds in much the same way as found in other small terns.
文摘The California least tern （Sternula antillarum browni） is an endangered species. The two largest colonies of this bird species in the San Francisco Bay, California, USA, are located 23 km apart at Alameda Point and Hayward Regional Shoreline. The Alameda Point colony, on the former Naval Air Station, Alameda, has grown at an average rate of 9.2% per year since its discovery in 1976 and has a nesting density ranging from 1-153 nests per ha. Long-term breeding success at Alameda has averaged 0.86 fledglings per breeding pair. Least tems began appearing in 2003, at an island in Hayward enhanced with substrate mediums and social attraction devices. Successful breeding attempts have been observed at the Hayward colony since 2006. The Hayward colony has grown at an average rate of 51.5% per year, has a nesting density ranging from 33-333 nests per ha and long-term breeding success average of 0.87 fledglings per breeding pair. Dropped fish have been collected from both colonies, and silversides （family Atherinopsidae） are the dominant prey. Alameda terns forage on a greater variety of species than the Hayward terns. The regression results indicate the importance of Northern anchovy （Engraulis mordax） to the breeding success of the Alameda colony.
