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
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
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
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
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
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
Breeding habitat of the Little Tern in a coast-river continuum was studied in relation to dam development. A habitat shift from coast to river occurred decades after dam construction as the dam-caused coastal erosion ...Breeding habitat of the Little Tern in a coast-river continuum was studied in relation to dam development. A habitat shift from coast to river occurred decades after dam construction as the dam-caused coastal erosion became manifested. On the other hand, the riverine habitat was affected by dam both positively and negatively. The positive aspect is the reduction of inundation risk for the habitat, and the negative effect is the vegetation development on the habitat. As a result, the bird did not abandon the riverine habitat although its physical characteristics may be considered as suboptimal. In addition, reasoning was given to explain why an artificially created habitat was not used by the bird. A general message resulting from this study is that species adaptive behaviors should be taken into consideration in assessing environmental impacts caused by human activities such as dam development.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
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
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
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.
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.
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).
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Breeding habitat of the Little Tern in a coast-river continuum was studied in relation to dam development. A habitat shift from coast to river occurred decades after dam construction as the dam-caused coastal erosion became manifested. On the other hand, the riverine habitat was affected by dam both positively and negatively. The positive aspect is the reduction of inundation risk for the habitat, and the negative effect is the vegetation development on the habitat. As a result, the bird did not abandon the riverine habitat although its physical characteristics may be considered as suboptimal. In addition, reasoning was given to explain why an artificially created habitat was not used by the bird. A general message resulting from this study is that species adaptive behaviors should be taken into consideration in assessing environmental impacts caused by human activities such as dam development.
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.
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.
