Nest site selection is a vital component of bird reproduction success,and an adaptive behavior conducted to decrease nest predation risk with avoiding external disturbances.Understanding patterns of nest site selectio...Nest site selection is a vital component of bird reproduction success,and an adaptive behavior conducted to decrease nest predation risk with avoiding external disturbances.Understanding patterns of nest site selection can provide insights into how species adapt to changes in their habitat and has important conservation implications.In this study,we used microhabitat variables and multi-scale data with a field survey of nest occurrence to determine nest site selection patterns and adaptive strategies of the breeding Oriental Storks(Ciconia boyciana)in different nest areas.Results demonstrate that the nest site microhabitat characteristics of the breeding Oriental Storks significantly differed among the three nesting areas,and nest height was higher in the middle and lower Yangtze River floodplain than in the Northeast China and Bohai Bay nest areas.The food resources and intensity of human disturbance had the greatest effects on the nest site selection of the breeding Oriental Storks.The intensity of human disturbance was positively correlated with the nest height of the breeding Oriental Storks in Bohai Bay and the middle and lower Yangtze River floodplain;however,nest height decreased with the abundance of food resources in the Northeast China nest area.Our findings indicate that the nest site selection patterns of Oriental Storks showed flexible adaptive strategies.In safer environments,nests were lower and closer to food resources,which allows parent storks to invest more in the nestlings.However,in areas where human activity was intense,nests were higher to ensure the safety of their offspring.Some measures that could be taken to improve the breeding habitat of Oriental Storks include increasing the percentage of wetland areas in nesting areas to enhance food resources availability and setting artificial nests at suitable heights in potential nesting grounds to encourage nesting.Finally,the establishment of soft barriers around the nesting areas could increase the safety of nests.展开更多
Oviparous female reptiles select nesting sites with optimal ecological factors that contribute to egg development. Chinese alligator (Alligator sinensis), an oviparous reptile, is a critically endangered crocodilian...Oviparous female reptiles select nesting sites with optimal ecological factors that contribute to egg development. Chinese alligator (Alligator sinensis), an oviparous reptile, is a critically endangered crocodilian with temperature-dependent sex determination. Research on its nesting behavior may facilitate the protection of this species. In this study, we monitored nesting behavior over eight years. We compared selected frequency of nest sites, distance from nest site to water, height from nest site top to the water surface, distance from nest site to human activity region, and canopy density between nest sites on the island and bank. The results showed that 45 nest sites were used by female alligators over eight years and each site was selected from one to 10 times. The selected frequency of nest site occurrence on the island was higher than that on the bank (P 〈 0.001). We observed that 88% of the individual alligators (15/17) showed different degrees of nest site fidelity. However, Chinese alligators might not always be loyal to only one nest site because of environmental changes or interspecific competition at nest sites. Our findings suggest that female alligators prefer to nest at island, which might be because of the nests on the island had a higher canopy density (P = 0.010) and were further from the human activity region (P 〈 0.001) than those on the bank did. It would be beneficial to reduce human activities during the breeding season and protect the vegetation of Chinese alligator habitats in the future.展开更多
The Marsh Grassbird Locustella pryeri is an uncommon songbird endemic to East Asia. Suitable nest- site selection can minimize nest loss, especially for open- cup and ground nesting passerines. We located and mon- ito...The Marsh Grassbird Locustella pryeri is an uncommon songbird endemic to East Asia. Suitable nest- site selection can minimize nest loss, especially for open- cup and ground nesting passerines. We located and mon- itored 66 Marsh Grassbird nests during 2004-2006 in Zhalong National Nature Reserve, northeast China, to identify characteristics of preferred nest sites. Marsh Grassbird nested mainly at sites with dense vegetation cover, high undergrowth and dry standing reed stalks, as well as small shallow ponds or rivers. Nests were more successful when they were placed higher above ground in patches with greater litter thickness. Predation and flooding were the leading causes of nest failure, accounting for at least 33 and 25 % of 24 nests lost, respectively. We ad- vocate retention of some unharvested reed patches and implementation of irrigation strategies that avoid increas- ing water levels during the breeding period (May-July) of Marsh Grassbirds.展开更多
Breeding philopatry is well known in the Black-headed Gull(Chroicocephalus ridibundus).Using a capture-markrecapture method,we studied if Black-headed Gulls show nest site tenacity and mate fidelity as well,and invest...Breeding philopatry is well known in the Black-headed Gull(Chroicocephalus ridibundus).Using a capture-markrecapture method,we studied if Black-headed Gulls show nest site tenacity and mate fidelity as well,and investigated if there are differences between a stable,and a newly established and fast-growing colony,as well as for differences between the center and edges of these colonies located in north-eastern Germany.We found a high level of nest site tenacity in the center of the stable colony on B?hmke Island,and lower degrees of nest site tenacity at the edge of the same colony and in the newly established and fast-growing colony on Riether Werder.Mate fidelity was very strong in all individuals which returned to their previous breeding place,regardless of the nest site location.展开更多
Background:The Hair-crested Drongo(Dicrurus hottentottus) exhibits a unique nest-dismantling behavior after the fledging of the young.One hypothesis explaining this behavior is dismantling one's own nest may reduc...Background:The Hair-crested Drongo(Dicrurus hottentottus) exhibits a unique nest-dismantling behavior after the fledging of the young.One hypothesis explaining this behavior is dismantling one's own nest may reduce potential competition for nest sites in the following breeding season because suitable breeding habitat might be limited,and sites are often reused.Methods:By comparing the habitat features at nest and random locations,we determined the nest habitat preference of the Hair-crested Drongo within Dongzhai National Nature Reserve,Henan,China.We also compared habitat features with nesting success to determine if any trends could be detected.Results:We found that nest tree height,diameter at breast height,live crown ratio,tree rank,and presence of overstory were significantly higher at nesting locations than random locations;slope,leaf litter cover percentage and depth,presence of understory and midstory,and number of trees per hectare were significantly lower at nest sites than random sites.Drongos preferred to use some tree species,such as Metasequoia glyptostroboides,Castanea mollissima,and Pterocarya stenoptera for nesting.Failed nests were often associated with habitat with higher percentage of leaf litter on the ground.Conclusion:Our data support that selection of nest sites does occur for this species at this site and therefore support the hypothesis that breeding habitat limitation could be one of the driving forces for the development of the nestdismantling behavior in this species.展开更多
Shorebird populations are declining worldwide,mainly due to human disturbances and loss of coastal wetlands.However,supratidal habitats as saltpans could play a role in buffering human impact.Saltpans have shown to be...Shorebird populations are declining worldwide,mainly due to human disturbances and loss of coastal wetlands.However,supratidal habitats as saltpans could play a role in buffering human impact.Saltpans have shown to be important as feeding or breeding sites of some shorebird species.A potential conservation strategy to increase shorebird populations in saltpans is to manipulate the cues that birds use to select optimal breeding habitat.Here it is hypothesized that shorebirds are attracted to bivalve shells due to the advantages they offer.Following this hypothesis,we supplemented a restored saltpan in 2019 and 2021 with bivalve shells,expecting an increase in the number of breeding birds’ nests.More than 75% of Kentish Plover(Charadrius alexandrinus) and Little Tern(Sternula albifrons) nests were found in patches with shells in both years.The best model for both species indicates that the presence of shells is the factor that most correlates with the location of nests.The probability of choosing one place over another to settle their nest increases in areas with an abundance of shells,double in the case of the Kentish Plover and triple in the case of the Little Tern.The result of this study may constitute a valuable tool for attracting birds to restored saltpans and could contribute to the success of expensive restoration projects where time is usually a constraint.展开更多
Background:Nesting trees and habitat represent the key factor underpinning stand selection by forest-dwelling birds.While two large European species–the black stork(Ciconia nigra L.)and white-tailed eagle(Haliaaetus ...Background:Nesting trees and habitat represent the key factor underpinning stand selection by forest-dwelling birds.While two large European species–the black stork(Ciconia nigra L.)and white-tailed eagle(Haliaaetus albicilla L.)–are known to require old,large trees for nesting,we sought to investigate further by comparing species requirements at the levels of the nesting tree,nesting stand,and landscape.This entailed a detailed examination of forest features within circles of radius 15 m surrounding 16 and 19 trees holding the nests of storks and eagles respectively.The same parameters were also checked in the vicinity of 50 randomly-selected mature trees.Results:Our results indicate different nesting preferences,with the eagles entirely confining themselves to Scots pine(Pinus sylvestris L.)–a species also chosen by black storks,which nevertheless regularly favour pedunculate oak(Quercus robur L.).Both species select trees of greater girth than the random ones,but white-tailed eagles choose to nest in the vicinity of patches of mature old stands with a loose canopy,to the extent that nesting trees and surrounding trees are of similar ages.In contrast,black storks prefer“veteran”trees with low-set crowns that are much older than any others in their vicinity.Nesting trees of the eagles are away from roads and close to lakes,while black storks do not avoid roads.Conclusions:As the ages of nesting trees of both species are greater than ages at final cutting in this region’s managed forest,silvicultural measures will need to be adjusted,with small patches of forest spared,or larger areas as“islands”of old-growth.Likewise,as tending and thinning are engaged in,certain trees with horizontal branches will need to remain,with relict trees also left untouched.As it happens,all of these recommendations are anyway key elements of close-to nature silviculture and multifunctional forestry.展开更多
Introduction:Reproductive success is a critical factor affecting avian demographics and can be influenced by many factors including nesting chronology,predation risk,and fine-scale nest site selection.Methods:We model...Introduction:Reproductive success is a critical factor affecting avian demographics and can be influenced by many factors including nesting chronology,predation risk,and fine-scale nest site selection.Methods:We modeled the relative influences of habitat-related covariates at six spatial scales(nest site:15-,40-,80-,120-,160-,and 200-m radii)on Eastern wild turkey(Meleagris gallopavo silvestris)nest site selection in two pine savannas managed by frequent prescribed fire(≤3 years)in southwestern Georgia during 2011-2013.Results:Nest site(15-m scale)habitat metrics(mean visual obstruction[cm]and canopy closure[%])had the greatest influence on nest site selection relative to covariates measured at larger spatial scales.Scaled odds ratios suggested that nests were 26.8% more likely to occur for every 10 cm increase in mean vegetation height with a range of 7.5 to 150.0 cm and 18.5% less likely to occur for every 10% increase in canopy closure with a range from 0.0 to 97.8%.Total ground cover,canopy closure,edge density,and percent land cover type(e.g.,mature pine,mixed pine/hardwood,shrub/scrub)had minimal influence on nest site selection.Conclusions:Management of pine savannas for turkey nest sites should focus on creating early-successional vegetation to conceal nests from potential predators.Additionally,we suggest that future studies consider evaluating the influence of spatial scale on turkey nest site selection.展开更多
Climate change and land use change pose a threat to the world’s biodiversity and have significant impacts on the geographic distribution and composition of many bird species,but little is known about how they affect ...Climate change and land use change pose a threat to the world’s biodiversity and have significant impacts on the geographic distribution and composition of many bird species,but little is known about how they affect threatened large-sized waterbird species that rely on agricultural landscapes.To address this gap,we investigated how climate and land use changes influence the distribution and nesting habitats of the globally vulnerable Lesser Adjutant(Leptoptilos javanicus) in Nepal.Between 2012 and 2023,we collected distribution data from 24 districts and nesting site information from 18 districts.In a nation-wide breeding survey conducted in 2020,we documented a total of 581 fledglings from 346 nests in 109 colonies.The ensemble model predicted a current potential distribution of 15%(21,637 km2) and a potential nesting habitat of 13%(19,651 km2) for the species in Nepal.The highest predicted current suitable distribution and nesting habitat was in Madhesh Province,while none was predicted in Karnali Province.The majority of this predicted distributional and nesting habitat falls on agricultural landscapes(>70%).Our model showed a likely range expansion of up to 15%(21,573 km2) for the distribution and up to 12%(17,482 km2) for the nesting habitat under SSP5-8.5 scenarios for the 2070s.The range expansion is expected to occur mainly within the current distribution and breeding range(Tarai and some regions of Siwalk),particularly in Lumbini and Sudurpashchim provinces,and extend to the northern portions(Siwalik and Mid-hill regions) in other provinces.However,the current Protected Areas and Important Bird and Biodiversity Areas are inadequate for providing optimal habitats for the species.Although the model suggests range expansion,the use of such novel habitats is primarily contingent on the availability and protection of large-sized trees(particularly Bombax ceiba,observed in 65% of colonies) in agricultural regions where nesting occurs.Therefore,our research suggests that agricultural landscapes should be prioritized in management plans for the conservation of the Lesser Adjutant in Nepal.展开更多
Nest-site selection patterns of Red-crowned cranes(Grus japonensis) and the effects of environmental variables were studied during the years of 2002-2008 in Zhalong Nature Reserve,Qiqihar city,northeast China.The ne...Nest-site selection patterns of Red-crowned cranes(Grus japonensis) and the effects of environmental variables were studied during the years of 2002-2008 in Zhalong Nature Reserve,Qiqihar city,northeast China.The nest-site selection pattern of Red-crowned cranes included two orders and three choices:the choice of nest-site habitat type within the macro-habitat order,nest zone selection and nest-site micro-habitat selection within the micro-habitat order.Various habitats(such as Carex swamps and reed fire districts) can be selected as the nest sites for Red-crowned cranes,of which reed swamps(93.15%) are given a preference.Factor Analysis reveals that the micro-habitat selection are affected by four main factors:fire,security(concealment /disturbance),incubation(conditions,nest-material),and food.Further analysis reveals that Red-crowned cranes have certain adaptability to the changes of nesting habitat quality in the Zhalong wetlands.In conclusion,fire,reeds,and water were the most important variables for nest-site habitat selection of Red-crowned Cranes in Zhalong Nature Reserve.展开更多
Background: The Emei Shan Liocichla(Liocichla omeiensis) is a globally vulnerable babbler, endemic to southwestern China. We investigated its nest predators, nest-site selection and nest success at the Laojunshan Nati...Background: The Emei Shan Liocichla(Liocichla omeiensis) is a globally vulnerable babbler, endemic to southwestern China. We investigated its nest predators, nest-site selection and nest success at the Laojunshan National Nature Reserve in Sichuan, China in order to identify the precise nesting-habitat requirements of the species, and to test whether the nest-site-selection cues, preferred by the Emei Shan Liocichla, are positively associated with nest success.Methods: We used infrared cameras to determine nest predators. We compared the microhabitat attributes between nest and random sites, as well as successful and failed nests. We used Binary Logistic Regression to determine the most important variables affecting nest-site selection of the Emei Shan Liocichla. We used the nest survival analysis in Program MARK to estimate daily nest survival rates(DSR). Nest success was calculated using the Mayfield method.Results: In total 56 nests were found. The DSR for all nests that contained at least one egg was 0.9564 ± 0.0091(95 % CI 0.9346–0.9711)(n = 40), while the total nest success was 27.5 %. We identified four categories of predators in 10 nest predation events, i.e. squirrels(n = 5), snakes(n = 3), raptors(n = 1) and wasps(n = 1). We found that:(1) nest predation was the primary reason for nest failure of the Emei Shan Liocichla,(2) tree cover, bamboo cover, liana abundance and distance to forest edge or gap were the most important variables affecting nest-site selection of this species, and(3) the nest-site-selection variables we measured appeared not to be positively associated with nest success.Conclusions: Our findings suggest that the Emei Shan Liocichla tended to select nest sites near forest edges or gaps with good concealment and that nest-site selection by this species was nonrandom but not necessarily adaptive. Reducing forest-edge development and protecting bamboo stands should be effective for conservation of this species.展开更多
Background:Floods and other extreme events have disastrous effects on wetland breeding birds.However,such events and their consequences are difficult to study due to their rarity and unpredictable occurrence.Methods:H...Background:Floods and other extreme events have disastrous effects on wetland breeding birds.However,such events and their consequences are difficult to study due to their rarity and unpredictable occurrence.Methods:Here we compared nest-sites chosen by Reed Parrotbills(Paradoxornis heudei) during June-August 2016 in Yongnianwa Wetlands,Hebei Province,China,before and after an extreme flooding event.Results:Twenty-three nests were identified before and 13 new nests after the flood.There was no significant difference in most nest-site characteristics,such as distance from the road,height of the reeds in which nests were built,or nest volume before or after the flood.However,nests after the flood were located significantly higher in the vegetation compared to before the flood(mean ± SE:1.17 ± 0.13 m vs.0.75 ± 0.26 m,p < 0.01).However,predation rate also increased significantly after the flood(67% vs.25%,p = 0.030).Conclusions:Our results suggested that Reed Parrotbills demonstrated behavioral plasticity in their nest-site selection.Thus,they appeared to increase the height of their nests in response to the drastically changing water levels in reed wetlands,to reduce the likelihood that their nests would be submerged again by flooding.However,predation rate also increased significantly after the flood,suggesting that the change in nest height to combat the threat of flooding made the nests more susceptible to other threats,such as predation.Animals' response to rare climatic events,such as flooding,may produce ecological traps if they make the animals more susceptible to other kinds of threats they are more likely to continue to encounter.展开更多
Background:Information pertaining to nest-site fidelity and breeding dispersal over successive years can help to better our understanding of how birds respond to nest predation.Methods:By using mist nets and tracking ...Background:Information pertaining to nest-site fidelity and breeding dispersal over successive years can help to better our understanding of how birds respond to nest predation.Methods:By using mist nets and tracking the color banded individuals,we investigated nest-site fidelity and breeding dispersal by Common Tailorbirds(Orthotomus sutorius)throughout a year and between successive years in 2017–2018.Results:The present study showed that Common Tailorbirds could produce up to four clutches per breeding season.When multiple broods were produced within a year,breeding pairs remained together,and the nest rebuilding rate was up to 92.2%,with only four cases(7.8%)in which birds reused their old nests.The dispersal distance between the nests during multiple breeding was found to be 10.0±10.5 m,and nest-site fidelity within the same year was 90.0%.By the second year of breeding,76.2%of individuals remained in the original breeding pairs,while for those that did switch partners,the females remained in the nest from the previous year and paired with new males.The dispersal distance between years was 26.5±41.9 m,and nest-site fidelity between different years was 80.1%.There was no significant difference between within-year and between-year dispersal distances.Moreover,there was no significant difference in the dispersal distance of rebuilt nests between birds that had experienced nest predation and those that had not.Conclusions:Our findings suggest that Common Tailorbirds maintain a high degree of fidelity to mates and nestsites,and nest predation had no significant effect on territorial changes or breeding dispersal distance between each breeding attempt.展开更多
Abiotic factors play an important role in species localisation,but biotic and anthropogenic predictors must also be considered in distribution modelling for models to be biologically meaningful.In this study,we formal...Abiotic factors play an important role in species localisation,but biotic and anthropogenic predictors must also be considered in distribution modelling for models to be biologically meaningful.In this study,we formalised the biotic predictors of nesting sites for four threatened Caucasian vultures by including species distribution models(wild ungulates,nesting tree species)as biotic layers in the vulture Maxent models.Maxent was applied in the R dismo package and the best set of the model parameters were defined in the R ENMeval package.Performance metrics were continuous Boyce index,Akaike's information criterion,the area under receiver operating curve and true skill statistics.We also calculated and evaluated the null models.Kernel density estimation method was applied to assess the overlap of vulture ecological niches in the environmental space.The accessibility of anthropogenic food resources was estimated using the Path Distance measure that considers elevation gradient.The availability of pine forests(Scots Pine)and wild ungulates(Alpine Chamois and Caucasian Goat)contributed the most(29.6%and 34.3%)to Cinereous Vulture(Aegypius monachus)nesting site model.Wild ungulate distribution also contributed significantly(about 46%)to the Bearded Vulture(Gypaetus barbatus)model.This scavenger nests in the highlands of the Caucasus at a minimum distance of 5–10 km from anthropogenic facilities.In contrast,livestock as a food source was most important in colony distribution of Griffon Vulture(Gyps fulvus).The contribution of distances to settlements and agricultural facilities to the model was 45%.The optimal distance from Egyptian Vulture(Neophron percnopterus)nesting sites to settlements was only 3–10 km,to livestock facilities no more than 15 km with the factor contribution of about 57%.Excluding the wild ungulate availability,the ecological niches of studied vultures overlapped significantly.Despite similar foraging and nesting requirements,Caucasian vultures are not pronounced nesting and trophic competitors due to the abundance of nesting sites,anthropogenic food sources and successful niche sharing.展开更多
Conserving species relies upon acquiring an understanding of their use of habitat,yet our understanding of the use of habitat by co-existing species of different guilds at microgeographic scales remains poor.In partic...Conserving species relies upon acquiring an understanding of their use of habitat,yet our understanding of the use of habitat by co-existing species of different guilds at microgeographic scales remains poor.In particular,the use of habitat by woodland species is of conservation concern because of widespread declines in woodland biodiversity.Woodland bird declines have been ascribed,in part,to high deer densities because their browsing reduces the availability of nesting sites and food.We quantify the microgeographic use of habitat by Roe Deer(Capreolus capreolus)and of Great Tits(Parus major),Blue Tits(Cyanistes caeruleus)and Pied Flycatchers(Ficedula hypoleuca)in a heterogenous woodland landscape.We examined the use of habitat at microgeographic scales by the deer and the three bird species in relation to whether the local habitat was flat or wet or had a path,fence or wall within a 25-m radius of 206 randomly selected locations.We first examined if the occupancy rates of nestboxes in those locations were correlated with the number of Roe Deer lays and second,examined if the use of habitat by the Roe Deer and the bird species were associated with each of the habitat features that we quantified.We begin by showing that the use of habitat by Roe Deer is incongruent with the use of habitat by Great Tits,Blue Tits and Pied Flycatchers during the breeding season.Also,whilst all three bird species showed no,or weak,habitat preferences,the Roe Deer preferred daytime lay sites that were in flat areas of wet woodland close to paths,whilst there were no significant effects of the presence of fences and walls.These findings show that the Roe Deer and the three bird species differ in the use of habitat within a heterogenous woodland landscape,meaning that their use of habitat did not overlap at microgeographic scales.Meanwhile,the deer showed preferences for flat areas of wet woodland,whilst none of the bird species exhibited such preferences,and we discuss the implications of our findings for the management of woodlands.展开更多
基金supported by the National Natural Science Foundation of China(Grant No.32171530 and 31472020)。
文摘Nest site selection is a vital component of bird reproduction success,and an adaptive behavior conducted to decrease nest predation risk with avoiding external disturbances.Understanding patterns of nest site selection can provide insights into how species adapt to changes in their habitat and has important conservation implications.In this study,we used microhabitat variables and multi-scale data with a field survey of nest occurrence to determine nest site selection patterns and adaptive strategies of the breeding Oriental Storks(Ciconia boyciana)in different nest areas.Results demonstrate that the nest site microhabitat characteristics of the breeding Oriental Storks significantly differed among the three nesting areas,and nest height was higher in the middle and lower Yangtze River floodplain than in the Northeast China and Bohai Bay nest areas.The food resources and intensity of human disturbance had the greatest effects on the nest site selection of the breeding Oriental Storks.The intensity of human disturbance was positively correlated with the nest height of the breeding Oriental Storks in Bohai Bay and the middle and lower Yangtze River floodplain;however,nest height decreased with the abundance of food resources in the Northeast China nest area.Our findings indicate that the nest site selection patterns of Oriental Storks showed flexible adaptive strategies.In safer environments,nests were lower and closer to food resources,which allows parent storks to invest more in the nestlings.However,in areas where human activity was intense,nests were higher to ensure the safety of their offspring.Some measures that could be taken to improve the breeding habitat of Oriental Storks include increasing the percentage of wetland areas in nesting areas to enhance food resources availability and setting artificial nests at suitable heights in potential nesting grounds to encourage nesting.Finally,the establishment of soft barriers around the nesting areas could increase the safety of nests.
基金supported by the Major Research Plan of the National Natural Science Foundation of China (Nos. 31230010 and 31530087)the National Key Program (2016YFC0503200) from Ministry of Science and Technology of China+1 种基金a special grant from the State Forestry Administrationthe Fundamental Research Funds for the Central Universities of China
文摘Oviparous female reptiles select nesting sites with optimal ecological factors that contribute to egg development. Chinese alligator (Alligator sinensis), an oviparous reptile, is a critically endangered crocodilian with temperature-dependent sex determination. Research on its nesting behavior may facilitate the protection of this species. In this study, we monitored nesting behavior over eight years. We compared selected frequency of nest sites, distance from nest site to water, height from nest site top to the water surface, distance from nest site to human activity region, and canopy density between nest sites on the island and bank. The results showed that 45 nest sites were used by female alligators over eight years and each site was selected from one to 10 times. The selected frequency of nest site occurrence on the island was higher than that on the bank (P 〈 0.001). We observed that 88% of the individual alligators (15/17) showed different degrees of nest site fidelity. However, Chinese alligators might not always be loyal to only one nest site because of environmental changes or interspecific competition at nest sites. Our findings suggest that female alligators prefer to nest at island, which might be because of the nests on the island had a higher canopy density (P = 0.010) and were further from the human activity region (P 〈 0.001) than those on the bank did. It would be beneficial to reduce human activities during the breeding season and protect the vegetation of Chinese alligator habitats in the future.
基金supported by the National Natural Science Foundation of China(Grant No.3037022141310302+1 种基金41001026)the Fundamental Research Funds for the Central Universities of China(Grant No.DL12CA09)
文摘The Marsh Grassbird Locustella pryeri is an uncommon songbird endemic to East Asia. Suitable nest- site selection can minimize nest loss, especially for open- cup and ground nesting passerines. We located and mon- itored 66 Marsh Grassbird nests during 2004-2006 in Zhalong National Nature Reserve, northeast China, to identify characteristics of preferred nest sites. Marsh Grassbird nested mainly at sites with dense vegetation cover, high undergrowth and dry standing reed stalks, as well as small shallow ponds or rivers. Nests were more successful when they were placed higher above ground in patches with greater litter thickness. Predation and flooding were the leading causes of nest failure, accounting for at least 33 and 25 % of 24 nests lost, respectively. We ad- vocate retention of some unharvested reed patches and implementation of irrigation strategies that avoid increas- ing water levels during the breeding period (May-July) of Marsh Grassbirds.
文摘Breeding philopatry is well known in the Black-headed Gull(Chroicocephalus ridibundus).Using a capture-markrecapture method,we studied if Black-headed Gulls show nest site tenacity and mate fidelity as well,and investigated if there are differences between a stable,and a newly established and fast-growing colony,as well as for differences between the center and edges of these colonies located in north-eastern Germany.We found a high level of nest site tenacity in the center of the stable colony on B?hmke Island,and lower degrees of nest site tenacity at the edge of the same colony and in the newly established and fast-growing colony on Riether Werder.Mate fidelity was very strong in all individuals which returned to their previous breeding place,regardless of the nest site location.
基金support by Dongzhai National Nature Reserve for conducting this studyFunding and support was provided by National Science Foundation East Asia Pacific Summer Institute (EAPSI)+2 种基金Chinese Ministry of Science and TechnologyChina Science and Technology Exchange Center Further funding and support was provided by Alabama A&M University and Beijing Normal University
文摘Background:The Hair-crested Drongo(Dicrurus hottentottus) exhibits a unique nest-dismantling behavior after the fledging of the young.One hypothesis explaining this behavior is dismantling one's own nest may reduce potential competition for nest sites in the following breeding season because suitable breeding habitat might be limited,and sites are often reused.Methods:By comparing the habitat features at nest and random locations,we determined the nest habitat preference of the Hair-crested Drongo within Dongzhai National Nature Reserve,Henan,China.We also compared habitat features with nesting success to determine if any trends could be detected.Results:We found that nest tree height,diameter at breast height,live crown ratio,tree rank,and presence of overstory were significantly higher at nesting locations than random locations;slope,leaf litter cover percentage and depth,presence of understory and midstory,and number of trees per hectare were significantly lower at nest sites than random sites.Drongos preferred to use some tree species,such as Metasequoia glyptostroboides,Castanea mollissima,and Pterocarya stenoptera for nesting.Failed nests were often associated with habitat with higher percentage of leaf litter on the ground.Conclusion:Our data support that selection of nest sites does occur for this species at this site and therefore support the hypothesis that breeding habitat limitation could be one of the driving forces for the development of the nestdismantling behavior in this species.
基金Servicio de Gestión del Medio Natural-Delegación de Cádiz from Consejería de Sostenibilidad, Medioambiente y Economía Azul (regional government)Saltpan Initiative Project (MAVA Foundation) and MEDARTSALT project (EU-ENICBC) provided the funding for the studyfunded by the Margarita Salas Grant (2021-067/PN/MS-RECUAL/CD) from the Ministry of Universities of the Government of Spain and the European Union。
文摘Shorebird populations are declining worldwide,mainly due to human disturbances and loss of coastal wetlands.However,supratidal habitats as saltpans could play a role in buffering human impact.Saltpans have shown to be important as feeding or breeding sites of some shorebird species.A potential conservation strategy to increase shorebird populations in saltpans is to manipulate the cues that birds use to select optimal breeding habitat.Here it is hypothesized that shorebirds are attracted to bivalve shells due to the advantages they offer.Following this hypothesis,we supplemented a restored saltpan in 2019 and 2021 with bivalve shells,expecting an increase in the number of breeding birds’ nests.More than 75% of Kentish Plover(Charadrius alexandrinus) and Little Tern(Sternula albifrons) nests were found in patches with shells in both years.The best model for both species indicates that the presence of shells is the factor that most correlates with the location of nests.The probability of choosing one place over another to settle their nest increases in areas with an abundance of shells,double in the case of the Kentish Plover and triple in the case of the Little Tern.The result of this study may constitute a valuable tool for attracting birds to restored saltpans and could contribute to the success of expensive restoration projects where time is usually a constraint.
文摘Background:Nesting trees and habitat represent the key factor underpinning stand selection by forest-dwelling birds.While two large European species–the black stork(Ciconia nigra L.)and white-tailed eagle(Haliaaetus albicilla L.)–are known to require old,large trees for nesting,we sought to investigate further by comparing species requirements at the levels of the nesting tree,nesting stand,and landscape.This entailed a detailed examination of forest features within circles of radius 15 m surrounding 16 and 19 trees holding the nests of storks and eagles respectively.The same parameters were also checked in the vicinity of 50 randomly-selected mature trees.Results:Our results indicate different nesting preferences,with the eagles entirely confining themselves to Scots pine(Pinus sylvestris L.)–a species also chosen by black storks,which nevertheless regularly favour pedunculate oak(Quercus robur L.).Both species select trees of greater girth than the random ones,but white-tailed eagles choose to nest in the vicinity of patches of mature old stands with a loose canopy,to the extent that nesting trees and surrounding trees are of similar ages.In contrast,black storks prefer“veteran”trees with low-set crowns that are much older than any others in their vicinity.Nesting trees of the eagles are away from roads and close to lakes,while black storks do not avoid roads.Conclusions:As the ages of nesting trees of both species are greater than ages at final cutting in this region’s managed forest,silvicultural measures will need to be adjusted,with small patches of forest spared,or larger areas as“islands”of old-growth.Likewise,as tending and thinning are engaged in,certain trees with horizontal branches will need to remain,with relict trees also left untouched.As it happens,all of these recommendations are anyway key elements of close-to nature silviculture and multifunctional forestry.
基金funding provided by the Georgia Wildlife Resources Division through the Wildlife Restoration Program(Grant No.W75)。
文摘Introduction:Reproductive success is a critical factor affecting avian demographics and can be influenced by many factors including nesting chronology,predation risk,and fine-scale nest site selection.Methods:We modeled the relative influences of habitat-related covariates at six spatial scales(nest site:15-,40-,80-,120-,160-,and 200-m radii)on Eastern wild turkey(Meleagris gallopavo silvestris)nest site selection in two pine savannas managed by frequent prescribed fire(≤3 years)in southwestern Georgia during 2011-2013.Results:Nest site(15-m scale)habitat metrics(mean visual obstruction[cm]and canopy closure[%])had the greatest influence on nest site selection relative to covariates measured at larger spatial scales.Scaled odds ratios suggested that nests were 26.8% more likely to occur for every 10 cm increase in mean vegetation height with a range of 7.5 to 150.0 cm and 18.5% less likely to occur for every 10% increase in canopy closure with a range from 0.0 to 97.8%.Total ground cover,canopy closure,edge density,and percent land cover type(e.g.,mature pine,mixed pine/hardwood,shrub/scrub)had minimal influence on nest site selection.Conclusions:Management of pine savannas for turkey nest sites should focus on creating early-successional vegetation to conceal nests from potential predators.Additionally,we suggest that future studies consider evaluating the influence of spatial scale on turkey nest site selection.
基金This work has been supported by CAS-SEABRI(Y4ZK111B01)In-ternational Science,and Technology Commissioner of Yunnan Province(202203AK140027)+2 种基金Yunnan Province Science and Technology Depart-ment(202203AP140007)Rufford Small Grants Foundation(31372-2)Tribhuvan University National Priority Area Research Grant(TU-NPAR-2078/79-ERG-04)。
文摘Climate change and land use change pose a threat to the world’s biodiversity and have significant impacts on the geographic distribution and composition of many bird species,but little is known about how they affect threatened large-sized waterbird species that rely on agricultural landscapes.To address this gap,we investigated how climate and land use changes influence the distribution and nesting habitats of the globally vulnerable Lesser Adjutant(Leptoptilos javanicus) in Nepal.Between 2012 and 2023,we collected distribution data from 24 districts and nesting site information from 18 districts.In a nation-wide breeding survey conducted in 2020,we documented a total of 581 fledglings from 346 nests in 109 colonies.The ensemble model predicted a current potential distribution of 15%(21,637 km2) and a potential nesting habitat of 13%(19,651 km2) for the species in Nepal.The highest predicted current suitable distribution and nesting habitat was in Madhesh Province,while none was predicted in Karnali Province.The majority of this predicted distributional and nesting habitat falls on agricultural landscapes(>70%).Our model showed a likely range expansion of up to 15%(21,573 km2) for the distribution and up to 12%(17,482 km2) for the nesting habitat under SSP5-8.5 scenarios for the 2070s.The range expansion is expected to occur mainly within the current distribution and breeding range(Tarai and some regions of Siwalk),particularly in Lumbini and Sudurpashchim provinces,and extend to the northern portions(Siwalik and Mid-hill regions) in other provinces.However,the current Protected Areas and Important Bird and Biodiversity Areas are inadequate for providing optimal habitats for the species.Although the model suggests range expansion,the use of such novel habitats is primarily contingent on the availability and protection of large-sized trees(particularly Bombax ceiba,observed in 65% of colonies) in agricultural regions where nesting occurs.Therefore,our research suggests that agricultural landscapes should be prioritized in management plans for the conservation of the Lesser Adjutant in Nepal.
基金supported by the 11th Five-Year National Science and Technology plans to support key project (No. 2008BADB0B01)the Program for New Century Excellent Talents in Universities, the National Natural Science Foundation of China (No. 30670350 and 31070345)
文摘Nest-site selection patterns of Red-crowned cranes(Grus japonensis) and the effects of environmental variables were studied during the years of 2002-2008 in Zhalong Nature Reserve,Qiqihar city,northeast China.The nest-site selection pattern of Red-crowned cranes included two orders and three choices:the choice of nest-site habitat type within the macro-habitat order,nest zone selection and nest-site micro-habitat selection within the micro-habitat order.Various habitats(such as Carex swamps and reed fire districts) can be selected as the nest sites for Red-crowned cranes,of which reed swamps(93.15%) are given a preference.Factor Analysis reveals that the micro-habitat selection are affected by four main factors:fire,security(concealment /disturbance),incubation(conditions,nest-material),and food.Further analysis reveals that Red-crowned cranes have certain adaptability to the changes of nesting habitat quality in the Zhalong wetlands.In conclusion,fire,reeds,and water were the most important variables for nest-site habitat selection of Red-crowned Cranes in Zhalong Nature Reserve.
基金supported by the National Natural Science Foundation of China(No.31272330)the Scientific Research Innovation Team Projects of Leshan Normal University
文摘Background: The Emei Shan Liocichla(Liocichla omeiensis) is a globally vulnerable babbler, endemic to southwestern China. We investigated its nest predators, nest-site selection and nest success at the Laojunshan National Nature Reserve in Sichuan, China in order to identify the precise nesting-habitat requirements of the species, and to test whether the nest-site-selection cues, preferred by the Emei Shan Liocichla, are positively associated with nest success.Methods: We used infrared cameras to determine nest predators. We compared the microhabitat attributes between nest and random sites, as well as successful and failed nests. We used Binary Logistic Regression to determine the most important variables affecting nest-site selection of the Emei Shan Liocichla. We used the nest survival analysis in Program MARK to estimate daily nest survival rates(DSR). Nest success was calculated using the Mayfield method.Results: In total 56 nests were found. The DSR for all nests that contained at least one egg was 0.9564 ± 0.0091(95 % CI 0.9346–0.9711)(n = 40), while the total nest success was 27.5 %. We identified four categories of predators in 10 nest predation events, i.e. squirrels(n = 5), snakes(n = 3), raptors(n = 1) and wasps(n = 1). We found that:(1) nest predation was the primary reason for nest failure of the Emei Shan Liocichla,(2) tree cover, bamboo cover, liana abundance and distance to forest edge or gap were the most important variables affecting nest-site selection of this species, and(3) the nest-site-selection variables we measured appeared not to be positively associated with nest success.Conclusions: Our findings suggest that the Emei Shan Liocichla tended to select nest sites near forest edges or gaps with good concealment and that nest-site selection by this species was nonrandom but not necessarily adaptive. Reducing forest-edge development and protecting bamboo stands should be effective for conservation of this species.
基金supported by the National Natural Science Foundation of China(Nos.31672303 to CY,31472013 and 31772453 to WL)
文摘Background:Floods and other extreme events have disastrous effects on wetland breeding birds.However,such events and their consequences are difficult to study due to their rarity and unpredictable occurrence.Methods:Here we compared nest-sites chosen by Reed Parrotbills(Paradoxornis heudei) during June-August 2016 in Yongnianwa Wetlands,Hebei Province,China,before and after an extreme flooding event.Results:Twenty-three nests were identified before and 13 new nests after the flood.There was no significant difference in most nest-site characteristics,such as distance from the road,height of the reeds in which nests were built,or nest volume before or after the flood.However,nests after the flood were located significantly higher in the vegetation compared to before the flood(mean ± SE:1.17 ± 0.13 m vs.0.75 ± 0.26 m,p < 0.01).However,predation rate also increased significantly after the flood(67% vs.25%,p = 0.030).Conclusions:Our results suggested that Reed Parrotbills demonstrated behavioral plasticity in their nest-site selection.Thus,they appeared to increase the height of their nests in response to the drastically changing water levels in reed wetlands,to reduce the likelihood that their nests would be submerged again by flooding.However,predation rate also increased significantly after the flood,suggesting that the change in nest height to combat the threat of flooding made the nests more susceptible to other threats,such as predation.Animals' response to rare climatic events,such as flooding,may produce ecological traps if they make the animals more susceptible to other kinds of threats they are more likely to continue to encounter.
基金funded by the National Natural Science Foundation of China(Nos.31472013 and 31772453 to WL)
文摘Background:Information pertaining to nest-site fidelity and breeding dispersal over successive years can help to better our understanding of how birds respond to nest predation.Methods:By using mist nets and tracking the color banded individuals,we investigated nest-site fidelity and breeding dispersal by Common Tailorbirds(Orthotomus sutorius)throughout a year and between successive years in 2017–2018.Results:The present study showed that Common Tailorbirds could produce up to four clutches per breeding season.When multiple broods were produced within a year,breeding pairs remained together,and the nest rebuilding rate was up to 92.2%,with only four cases(7.8%)in which birds reused their old nests.The dispersal distance between the nests during multiple breeding was found to be 10.0±10.5 m,and nest-site fidelity within the same year was 90.0%.By the second year of breeding,76.2%of individuals remained in the original breeding pairs,while for those that did switch partners,the females remained in the nest from the previous year and paired with new males.The dispersal distance between years was 26.5±41.9 m,and nest-site fidelity between different years was 80.1%.There was no significant difference between within-year and between-year dispersal distances.Moreover,there was no significant difference in the dispersal distance of rebuilt nests between birds that had experienced nest predation and those that had not.Conclusions:Our findings suggest that Common Tailorbirds maintain a high degree of fidelity to mates and nestsites,and nest predation had no significant effect on territorial changes or breeding dispersal distance between each breeding attempt.
基金the State Assignment,project 075-00347-19-00(Patterns of the spatiotemporal dynamics of meadow and forest ecosystems in mountainous areas(Russian Western and Central Caucasus)WWF's‘Save the Forest-Home of Raptors’project(2020-2022).
文摘Abiotic factors play an important role in species localisation,but biotic and anthropogenic predictors must also be considered in distribution modelling for models to be biologically meaningful.In this study,we formalised the biotic predictors of nesting sites for four threatened Caucasian vultures by including species distribution models(wild ungulates,nesting tree species)as biotic layers in the vulture Maxent models.Maxent was applied in the R dismo package and the best set of the model parameters were defined in the R ENMeval package.Performance metrics were continuous Boyce index,Akaike's information criterion,the area under receiver operating curve and true skill statistics.We also calculated and evaluated the null models.Kernel density estimation method was applied to assess the overlap of vulture ecological niches in the environmental space.The accessibility of anthropogenic food resources was estimated using the Path Distance measure that considers elevation gradient.The availability of pine forests(Scots Pine)and wild ungulates(Alpine Chamois and Caucasian Goat)contributed the most(29.6%and 34.3%)to Cinereous Vulture(Aegypius monachus)nesting site model.Wild ungulate distribution also contributed significantly(about 46%)to the Bearded Vulture(Gypaetus barbatus)model.This scavenger nests in the highlands of the Caucasus at a minimum distance of 5–10 km from anthropogenic facilities.In contrast,livestock as a food source was most important in colony distribution of Griffon Vulture(Gyps fulvus).The contribution of distances to settlements and agricultural facilities to the model was 45%.The optimal distance from Egyptian Vulture(Neophron percnopterus)nesting sites to settlements was only 3–10 km,to livestock facilities no more than 15 km with the factor contribution of about 57%.Excluding the wild ungulate availability,the ecological niches of studied vultures overlapped significantly.Despite similar foraging and nesting requirements,Caucasian vultures are not pronounced nesting and trophic competitors due to the abundance of nesting sites,anthropogenic food sources and successful niche sharing.
文摘Conserving species relies upon acquiring an understanding of their use of habitat,yet our understanding of the use of habitat by co-existing species of different guilds at microgeographic scales remains poor.In particular,the use of habitat by woodland species is of conservation concern because of widespread declines in woodland biodiversity.Woodland bird declines have been ascribed,in part,to high deer densities because their browsing reduces the availability of nesting sites and food.We quantify the microgeographic use of habitat by Roe Deer(Capreolus capreolus)and of Great Tits(Parus major),Blue Tits(Cyanistes caeruleus)and Pied Flycatchers(Ficedula hypoleuca)in a heterogenous woodland landscape.We examined the use of habitat at microgeographic scales by the deer and the three bird species in relation to whether the local habitat was flat or wet or had a path,fence or wall within a 25-m radius of 206 randomly selected locations.We first examined if the occupancy rates of nestboxes in those locations were correlated with the number of Roe Deer lays and second,examined if the use of habitat by the Roe Deer and the bird species were associated with each of the habitat features that we quantified.We begin by showing that the use of habitat by Roe Deer is incongruent with the use of habitat by Great Tits,Blue Tits and Pied Flycatchers during the breeding season.Also,whilst all three bird species showed no,or weak,habitat preferences,the Roe Deer preferred daytime lay sites that were in flat areas of wet woodland close to paths,whilst there were no significant effects of the presence of fences and walls.These findings show that the Roe Deer and the three bird species differ in the use of habitat within a heterogenous woodland landscape,meaning that their use of habitat did not overlap at microgeographic scales.Meanwhile,the deer showed preferences for flat areas of wet woodland,whilst none of the bird species exhibited such preferences,and we discuss the implications of our findings for the management of woodlands.