It is widely accepted that the Marginal Value Theorem (MVT) describes optimal foraging strategies of animals and the mechanism proposed by the MVT has been supported by a number of field observations. However, finding...It is widely accepted that the Marginal Value Theorem (MVT) describes optimal foraging strategies of animals and the mechanism proposed by the MVT has been supported by a number of field observations. However, findings of many researchers indicate that in natural conditions foragers do not always behave according to the MVT. To address this inconsistency, in a series of computer simulation experiments, we examined the behaviour of four types of foragers having specific foraging efficiencies and using the MVT strategies in 15 different landscapes in an ideal environment (no intra-and inter-specific interactions). We used data on elk (Cervus elaphus) to construct our virtual forager. Contrary to the widely accepted understanding of the MVT (residence time in a patch should be longer in environments where travel time between patches is longer) we found that in environments with the same average patch quality and varying average travel times between patches, patch residence times of some foragers are not affected by travel times. Based on our analysis we propose a mechanism responsible for this observation and formulate the perfect forager theorem (PFT). We also introduce the concepts of a foraging coefficient (F) and foragers’ hub (α), and propose a model to describe the relationship between the perfect forager and all other forager types.展开更多
Lesser kestrels Falco naumanni are migratory central-place foragers that breed in dynamic arable landscapes. After arriving from migration, kestrels have no knowledge of the distribution of crops, and consequently pre...Lesser kestrels Falco naumanni are migratory central-place foragers that breed in dynamic arable landscapes. After arriving from migration, kestrels have no knowledge of the distribution of crops, and consequently prey, around their colony. The energy demand of pairs increases as breeding season progresses, but at the same time prey abundance, and their knowledge on prey distribution, also increases. Wind can have a strong influence on flight cost and kestrels should try to reduce energy expendi- ture when possible. When prey abundance is low, kestrels have little knowledge of prey distribution, and pairs have no chicks, they could reduce foraging flight cost by leaving the colony with tailwinds. When prey is abundant, knowledge on prey distribu- tion has increased, and chick demand is high, kestrels should fly to the most favorable foraging patches. We analyzed foraging trips directions in a lesser kestrel colony along the breeding season and in relation to wind speed and direction. We recorded 664 foraging trips from 19 individuals using GPS-dataloggers. We found that outward flights direction changed from uniform to a concentrated distribution along the season, as prey abundance and individual experience increased. We also found a temporal trend in the angular difference between outward flights and wind directions, with low values early in the season and then increa- sing as expected, but again low values at the end, contrary to expectation. Results suggest changes in kestrels foraging strategy along the season in relation to wind. Kestrels depart more with tailwinds in exploratory flights early in the season, while there is a spurious coincidence in direction to preferred foraging patches and dominant wind direction at the end [Current Zoology 60 （5）： 604-615, 2014].展开更多
Artifcial light at night(ALAN)is a common anthropogenic disturbance,which alters animal behavior.However,little is known about the impact of the spectral composition of ALAN and co-occurring predation risk on the beha...Artifcial light at night(ALAN)is a common anthropogenic disturbance,which alters animal behavior.However,little is known about the impact of the spectral composition of ALAN and co-occurring predation risk on the behavior of aquatic organisms.We experimentally investigated how ALAN of different spectra(cool white LED and HPS light)affects the behavior and foraging of Gammarus jazdzewskii(Amphipoda)on chironomid prey,both as a single stressor and in combination with an olfactory predation cue.Gammarids exposed to ALAN in the absence of predation cues consumed less,compared with darkness,mainly due to their lower activity.Moreover,gammarids showed a stronger response to LED light,spending more time in the shelter and increasing prey handling time in this treatment.The addition of predation cues did not enhance the negative impact of ALAN on the foraging success.Gammarids maintained similar consumption levels as in the ALAN treatment without predation cues and in darkness with predation cues.However,gammarids in LED light altered their behavior in response to predation threat:they decreased prey handling time and consumed prey faster,which may have compensated for the higher food demand in stressful conditions.They also tended to exhibit risky behavior,leaving the shelter and moving towards the lit area,presumably to escape and avoid the combined effects of light and predation cues.Therefore,when assessing the effects of ALAN on organisms,light quality and co-occurring biotic factors should be considered,as predator pressure is common in natural environments.展开更多
Grain soybean(Glycine max(L.)Merr.)shows potential as a forage crop following its introduction from low to high latitudes due to in its growth phenotype.However,the application of this approach is impeded by the diver...Grain soybean(Glycine max(L.)Merr.)shows potential as a forage crop following its introduction from low to high latitudes due to in its growth phenotype.However,the application of this approach is impeded by the diverse ecological types of soybean,their adaptability to the introduction,and the uncertainty surrounding the growth phenotype post-introduction.This study introduced 24 grain soybean varieties from low-latitude regions(22-31°N)to the high-latitude northwestern Loess Plateau(39°N)between 2018 and 2019.The growth phenotypes were observed,and their forage productivity potential was assessed.All varieties displayed delayed flowering following cross-latitude introduction,with the vegetative growth phase of some varieties even exceeding their entire growth duration at their origin.Rapid dry matter accumulation rates indicated growth adaptation performance and formed the basis for soybean forage yield.Varieties from the tropical South China region exhibited significant yield advantages,with dry matter yields of 8.97-14.68 t ha^(-1)and crude protein yields of 1.44-2.51 t ha^(-1).Varieties HX3 and GX7 from this region demonstrated optimal growth adaptability and productivity in the cross-latitude environment,achieving the highest dry matter yields of 14.68 and 13.86 t ha^(-1),respectively.As a result,HX3 and GX7 are recommended for local farming systems to provide high-quality forage.The cross-latitude introduction of soybean is proposed as a viable and efficient strategy for forage improvement and application.展开更多
Two widespread bird species in Sri Lanka’s dry zone,Pycnonotus cafer(Red-vented Bulbul,RVBB)and Pycnonotus luteolus(White-browed Bulbul,WBBB),were studied to understand their foraging dynamics and ecology.The researc...Two widespread bird species in Sri Lanka’s dry zone,Pycnonotus cafer(Red-vented Bulbul,RVBB)and Pycnonotus luteolus(White-browed Bulbul,WBBB),were studied to understand their foraging dynamics and ecology.The research was conducted from October 2022 to February 2023 in Mihintale Sanctuary(80.30′11.24″E,8.21′04.63″N)and the Faculty of Applied Sciences,Rajarata University of Sri Lanka(80.502206″E,8.353090″N).Data were obtained through focal sampling,opportunistic observations,and mist netting.Both species predominantly foraged on twigs,using gleaning as the dominant food-handling technique.RVBB foraged mostly at the canopy level,while WBBB foraged primarily at the sub-canopy level.Fruits constituted the major food type for both species.RVBB and WBBB utilized 10 and 7 plant species,respectively,with Grewia helicterifolia being the primary foraging plant.Minimal foraging was observed on Croton sp.(RVBB)and Hugonia mistax(WBBB).The correlation between nutritional components and the consumption of both species revealed a preference for foods with lower protein,higher fat,and ash content.There was no linear correlation between gape width and fruit size(r=-0.21,P=0.69)for both species.The standardized dietary niche breadth indicated both species are specialists,with a high pairwise dietary niche overlap(0.9854).These findings highlight the niche-specific foraging adaptations of RVBB and WBBB within Mihintale,emphasizing their distinct strategies in utilizing plant species,fruit sizes,and foraging heights.Understanding such ecological dynamics is essential for habitat conservation efforts and ensuring the availability of key foraging resources for these species in the dry zone.展开更多
Food abundance and availability constitute fundamental determinants of foraging habitat quality for waterbirds, with high-quality foraging habitats playing a crucial role in supporting the survival and annual life cyc...Food abundance and availability constitute fundamental determinants of foraging habitat quality for waterbirds, with high-quality foraging habitats playing a crucial role in supporting the survival and annual life cycle of wintering populations. The ongoing degradation and loss of optimal habitats have forced wintering waterbirds to increasingly rely on alternative foraging sites and modify their behavioral adaptation strategies to cope with food scarcity. The Siberian Crane (Leucogeranus leucogeranus), a large-bodied endangered waterbird species characterized by specialized dietary preferences, demonstrates particular sensitivity to environmental alterations. Faced with diminishing suitable habitats and declining natural food resources, this species has progressively adapted to utilizing artificial habitats, including agricultural landscapes such as paddy fields and lotus ponds, as supplementary wintering foraging grounds to fulfill their energetic requirements. This study examines the hypothesis that Siberian Cranes adapt their foraging behavior through plastic behavioral strategies in artificial habitats under conditions of limited food availability, thereby enhancing population fitness. A comparative analysis of crane foraging behaviors was conducted between mudflats and lotus ponds throughout the 2023–2024 wintering period. This investigation focused on three critical environmental factors: food abundance, food burial depth, and sediment penetrability, examining their influence on foraging patterns across these distinct habitats. The results revealed significant inter-habitat differences: foraging success rates were substantially higher (p < 0.05) and food handling times markedly longer in lotus ponds compared to mudflats, whereas foraging effort and attempt frequency were significantly elevated in mudflat habitats. The superior food availability in lotus ponds facilitated enhanced foraging success rates, enabling cranes to accumulate essential energy reserves for winter survival. However, the deeper burial depth of lotus roots in these habitats required more intensive processing behaviors, including prolonged digging, breaking, and swallowing activities, which consequently increased handling time by approximately 40% and reduced foraging attempts by 25–30% compared to mudflat conditions. These behavioral trade-offs suggest that while lotus ponds provide adequate food resources, their structural characteristics may impose physiological constraints that limit their effectiveness as optimal foraging grounds for Siberian Cranes. These findings offer valuable insights into the behavioral plasticity of wintering Siberian Cranes response to spatial variations in food resource distribution, while contributing to our understanding of the ecological value of lotus roots as alternative winter food sources in artificial wetland ecosystems.展开更多
Understanding the fundamental drivers of large-scale species co-occurrence is a critical issue in ecology and conservation research. Here, we assessed foraging guilds, habitat type and disturbances as drivers of bird ...Understanding the fundamental drivers of large-scale species co-occurrence is a critical issue in ecology and conservation research. Here, we assessed foraging guilds, habitat type and disturbances as drivers of bird species co-occurrence in Ghana's Central Region over six months. Birds were sampled in 120 points across six different habitat types (farmland, forest reserve, urban area, coastal savannah, wetland, and mangrove), using the point-centred count technique. In total, 4060 individuals belonging to 216 species were recorded across all six habitat types. We found that co-occurring species were more similar in their foraging behaviour and habitat association. About 60% of the birds were found to co-occur randomly, 15% co-occurred negatively, and 25% co-occurred positively. Carnivores like the Black Heron (Egretta ardesiaca) and Spur-winged Lapwing (Vanellus spinosus) randomly co-occurred with other guild groups and were dominant in the mangroves and wetlands. Frugivores from forest reserves had only a 25% chance of randomly co-occurring with other birds and about a 60% chance of positively co-occurring with other birds. Our findings suggest that foraging guilds and habitat type are major factors driving bird co-occurrence and community assemblages in this West African suburban region.展开更多
Little Terns Sternula albifrons are estuarine birds extensively using increasingly urbanized coastal areas.Given the increased exposure of these ecosystems to anthropogenic activities,it is crucial to study the ecolog...Little Terns Sternula albifrons are estuarine birds extensively using increasingly urbanized coastal areas.Given the increased exposure of these ecosystems to anthropogenic activities,it is crucial to study the ecology of this species and interactions with human stressors to establish management measures.We collected regurgitates(n=182)and blood samples(n=48)to study Little Terns’diet,health condition and isotopic niche,and individually tracked breeding adults(n=9,during 2021 and 2022)at 2 sandy beaches 21 km apart and located within Ria Formosa Natural Park,Algarve,Portugal.Although both areas are adjacent to foraging coastal marine areas and an estuarine lagoon system with saltpans,they differ in human disturbance.We also compared breeding success and adult health measures between these 2 colonies.The main prey for both populations were Sand Smelts Atherina spp.and Gobies Pomatoschistus spp.,and no differences in δ^(13)C and δ^(15)N stable isotopic values between colonies were found.Tracking data revealed that individuals foraged in the surroundings of their breeding colonies.Entrance Channels and Ocean were the most frequently used habitats for foraging by individuals from the less disturbed colony.Adults from the more disturbed colony foraged mostly in Entrance Channels.Overall,all individuals tended to forage during daytime.There were no differences in health measures of individuals between colonies,though breeding success at the most disturbed colony was comparably lower.It is important to protect both breeding areas and adjacent foraging habitats for Little Terns,particularly given the expected increasing pressure from human activities on coastal areas worldwide.展开更多
Next-generation 6G networks seek to provide ultra-reliable and low-latency communications,necessitating network designs that are intelligent and adaptable.Network slicing has developed as an effective option for resou...Next-generation 6G networks seek to provide ultra-reliable and low-latency communications,necessitating network designs that are intelligent and adaptable.Network slicing has developed as an effective option for resource separation and service-level differentiation inside virtualized infrastructures.Nonetheless,sustaining elevated Quality of Service(QoS)in dynamic,resource-limited systems poses significant hurdles.This study introduces an innovative packet-based proactive end-to-end(ETE)resource management system that facilitates network slicing with improved resilience and proactivity.To get around the drawbacks of conventional reactive systems,we develop a cost-efficient slice provisioning architecture that takes into account limits on radio,processing,and transmission resources.The optimization issue is non-convex,NP-hard,and requires online resolution in a dynamic setting.We offer a hybrid solution that integrates an advanced Deep Reinforcement Learning(DRL)methodology with an Improved Manta-Ray Foraging Optimization(ImpMRFO)algorithm.The ImpMRFO utilizes Chebyshev chaotic mapping for the formation of a varied starting population and incorporates Lévy flight-based stochastic movement to avert premature convergence,hence facilitating improved exploration-exploitation trade-offs.The DRL model perpetually acquires optimum provisioning strategies via agent-environment interactions,whereas the ImpMRFO enhances policy performance for effective slice provisioning.The solution,developed in Python,is evaluated across several 6G slicing scenarios that include varied QoS profiles and traffic requirements.The DRL model perpetually acquires optimum provisioning methods via agent-environment interactions,while the ImpMRFO enhances policy performance for effective slice provisioning.The solution,developed in Python,is evaluated across several 6G slicing scenarios that include varied QoS profiles and traffic requirements.Experimental findings reveal that the proactive ETE system outperforms DRL models and non-resilient provisioning techniques.Our technique increases PSSRr,decreases average latency,and optimizes resource use.These results demonstrate that the hybrid architecture for robust,real-time,and scalable slice management in future 6G networks is feasible.展开更多
Abundant food supply is crucial for the survival of long-distance migratory birds.The continued population decline of the Spoon-billed Sandpiper(Calidris pygmeae),a critically endangered shorebird,is primarily attribu...Abundant food supply is crucial for the survival of long-distance migratory birds.The continued population decline of the Spoon-billed Sandpiper(Calidris pygmeae),a critically endangered shorebird,is primarily attributed to habitat loss and degradation.However,significant gaps remain in research on their diet and foraging habitat selection,limiting effective conservation and restoration efforts.In this study,we investigated the composition of macrobenthic communities,analyzing habitat and prey selection at the main foraging area of SBS in Tiaozini,Jiangsu Province of eastern China—their most critical staging site during southward migration.Our findings revealed 25 species of macrobenthos in foraging areas,with mobile epibenthos comprising the largest group by biomass,accounting for 73%,and having higher density and biomass nearshore.Observations of foraging Spoon-billed Sandpiper individuals indicated that shallow water habitats were their preferred foraging environments,where mobile epibenthos,which thrive in these habitats after the tide recedes,made up 81%of their biomass intake.We propose that shallow water habitats in intertidal mudflats serve as essential refuges for mobile epibenthos after tidal retreat,thereby providing Spoon-billed Sandpipers with access to high-quality food resources.Habitat protection efforts should prioritize habitats harboring extensive microhabitats with shallow water,especially the nearshore area,and further research is needed to explore the mechanisms underlying the formation of these microhabitats,with the ultimate goal of restoring more high-quality habitats for the Spoonbilled Sandpiper.展开更多
The authors regret that the scientific names of some species mentioned in the paper were incorrectly presented.The incorrect sci-entific names,their locations in the paper,correct spellings and refer-ences,are listed ...The authors regret that the scientific names of some species mentioned in the paper were incorrectly presented.The incorrect sci-entific names,their locations in the paper,correct spellings and refer-ences,are listed below.展开更多
Mammal distribution is shaped by different ecological and anthropogenic factors,and the pattern varies depending on their sensitivity thresholds,food and habitat preferences,ecological roles,and physical traits.The pr...Mammal distribution is shaped by different ecological and anthropogenic factors,and the pattern varies depending on their sensitivity thresholds,food and habitat preferences,ecological roles,and physical traits.The present study investigated the influence of ecological and anthropogenic factors on the distribution of mammal species communities across different trophic levels and body sizes in Myanmar's Htamanthi Wildlife Sanctuary(HWS).The values of mammal characteristics,ecological,and anthropogenic factors were analyzed in ArcMap software.Most of the large and small sized mammals,whose distribution decreases with elevation,were observed near the main streams.Across mammal tropic levels,the omnivores and herbivores were mostly observed farther from gold mining sites.In terms of forage plant effect on mammal community,floral forage plants and the presence of climber negatively affected mammal species across different trophic levels.Moreover,presence of resin trees also has a substantial impact on the distribution of medium-large animals and omnivorous mammals as trophic niche factors.Overall,our findings highlight the crucial role that ecological and anthropogenic factors play in shaping mammal distribution in the HWS.This underscores the importance of simultaneously conserving both habitat and mammal diversity in HWS,especially in the face of a changing climate and environment.展开更多
The “Greater Food” approach has replaced the older “taking grain production as a top priority” approach. Theimportance of feed and forage as the material basis for guaranteeing high-quality development of the live...The “Greater Food” approach has replaced the older “taking grain production as a top priority” approach. Theimportance of feed and forage as the material basis for guaranteeing high-quality development of the livestock industry has gradually become prominent. However, owing to the tradition of “both human staple food and animal feed relying on grain production” in China and the decoupling of feed crop planting and livestock farming, the risk of feed grain security has increased, especially as it relates to the supply of high-quality protein feed ingredients from abroad, which is facing a bottleneck. To ensure food security, effective domestic agricultural production should be adopted. Nevertheless, guaranteeing the supply of high-quality protein feed through domestic soybean production is difficult because of limited arable land;furthermore, pressure on the staple food supply is still extreme. In this article, the historical and realistic implications for the security risks of feed grain in China are analyzed. Proposals are made to separate staple food grains for humans from the feed grain supply for animals and to develop high-quality forage to reduce feed grain use. High-quality forage can be supplied via intercropping with grain crops in arable land and reseeding perennial legumes or grasses into natural grasslands. However, “managing forage for grain” needs to be supported via technical paths and policies as the forage industry develops to effectively increase the capacity to ensure feed grain security.展开更多
Social learning is a mechanism used by many species to effciently gain information about their environment.Although many animals live in an environment where members of other species are present,little is known about ...Social learning is a mechanism used by many species to effciently gain information about their environment.Although many animals live in an environment where members of other species are present,little is known about interspecifc social learning.Domesticated and urbanized species provide the opportunity to investigate whether nonhuman animals can learn from heterospecifcs such as humans,who are integral parts of their social landscape.Although domestic dogs Canis familiaris have been intensively researched for their ability to learn from humans,most studies have focused on dogs living as pets.However,free-ranging dogs represent the majority of the world’s dog population,they live alongside humans,scavenge on human refuse,and are subject to natural and sexual selection.Thus,free-ranging dogs with extensive exposure to humans and their artifacts provide the opportunity to investigate interspecifc social learning in a naturalistic setting,where learning from humans might be a beneft for them.Here we tested individual free-ranging dogs in a between-subject design:Dogs in the control group could spontaneously choose between two novel and differently patterned food-delivering boxes.In the experimental group,instead,dogs could frst observe an unfamiliar human approaching and eating from 1 of the 2 boxes.We provide the frst evidence that free-ranging dogs match the choice of an unfamiliar human.These results show that at least simple forms of interspecifc social learning might be involved in dogs’success in living alongside humans in a complex urbanized environment.展开更多
This paper comprehensively analyzes the Manta Ray Foraging Optimization(MRFO)algorithm and its integration into diverse academic fields.Introduced in 2020,the MRFO stands as a novel metaheuristic algorithm,drawing ins...This paper comprehensively analyzes the Manta Ray Foraging Optimization(MRFO)algorithm and its integration into diverse academic fields.Introduced in 2020,the MRFO stands as a novel metaheuristic algorithm,drawing inspiration from manta rays’unique foraging behaviors—specifically cyclone,chain,and somersault foraging.These biologically inspired strategies allow for effective solutions to intricate physical challenges.With its potent exploitation and exploration capabilities,MRFO has emerged as a promising solution for complex optimization problems.Its utility and benefits have found traction in numerous academic sectors.Since its inception in 2020,a plethora of MRFO-based research has been featured in esteemed international journals such as IEEE,Wiley,Elsevier,Springer,MDPI,Hindawi,and Taylor&Francis,as well as at international conference proceedings.This paper consolidates the available literature on MRFO applications,covering various adaptations like hybridized,improved,and other MRFO variants,alongside optimization challenges.Research trends indicate that 12%,31%,8%,and 49%of MRFO studies are distributed across these four categories respectively.展开更多
Extreme droughts are increasing in frequency and severity globally as a result of climate change.Developing understanding of species’responses to drought is crucial for their conservation,especially in regions experi...Extreme droughts are increasing in frequency and severity globally as a result of climate change.Developing understanding of species’responses to drought is crucial for their conservation,especially in regions experi-encing increased aridity.Although numerous studies have investigated birds’responses to drought,the emphasis has primarily been on landbirds.Drought can significantly alter the wetland environments that waterbirds inhabit,but the response of waterbirds to drought remains understudied.In this study,we surveyed the distri-bution and behavior of Oriental Storks(Ciconia boyciana)in Poyang Lake,which is the largest freshwater lake in China.Results indicate that drought-induced catchment areas at the lowest water level limited the total popu-lation size of Oriental Storks in the sub-lakes.Sub-lakes with large catchment areas at the lowest water level demonstrated a capacity to support a larger population of wintering Oriental Storks.Over time,Oriental Storks exhibited a gradual concentration in Changhu Lake,characterized by larger catchments,after resource depletion in sub-lakes with smaller catchments.Additionally,the duration of Oriental Storks’vigilance and moving be-haviors decreased significantly compared with that observed before the drought.After the drought,Oriental Storks increased their foraging efforts,as evidenced by increased presence in deeper water and reaching their heads and necks into deeper water to forage,higher search rates,but lower foraging rates.In accordance with area-restricted search theory,reductions in habitat quality resulting from drought,including extensive fish die-offs,forced Oriental Storks to increase their foraging efforts.Sustaining a specific water area in sub-lakes during droughts can preserve resource availability,which is crucial for the conservation of Oriental Storks.Imple-menting measures such as water level control and micro-modification of lake bottoms in sub-lakes might mitigate the impact of drought on the piscivorous Oriental Storks.展开更多
Recent advances in our understanding of avian chemical communication have highlighted the importance of olfaction in many aspects of avian life.Prior studies investigating predator avoidance behaviors in response to p...Recent advances in our understanding of avian chemical communication have highlighted the importance of olfaction in many aspects of avian life.Prior studies investigating predator avoidance behaviors in response to predator odor cues have produced mixed results across species and contexts.Here we assess if a community of birds in eastern Pennsylvania displays avoidance behaviors towards predator odor cues in a natural foraging setting.We use clay caterpillars to measure foraging activity by birds in the presence of predator(bobcat)urine,non-predator(rabbit)urine,and water controls in two different environmental contexts(field vs.forest).Although we detected a weak trend for birds to forage less at predator urine-treated sites,we found no significant difference in avian foraging between the site types.We did find that foraging rates between environmental contexts changed significantly over the course of the experiment,with forest sites showing decreasing foraging rates and field sites showing increasing foraging rates.Our results reinforce the published literature that avoidance of predator odors by birds may not be ubiquitous across contexts and species.展开更多
Many animals use color to signal their quality and/or behavioral motivations.Colorful signals have been well studied in the contexts of competi-tion and mate choice;however,the role of these signals in nonsexual,affil...Many animals use color to signal their quality and/or behavioral motivations.Colorful signals have been well studied in the contexts of competi-tion and mate choice;however,the role of these signals in nonsexual,affiliative relationships is not as well understood.Here,we used wild social groups of the cichlid fish Neolamprologus pulcher to investigate whether the size of a brightly colored facial patch was related to 1)individual quality,2)social dominance,and/or 3)affiliative relationships.Individuals with larger patches spent more time foraging and tended to perform more aggressive acts against conspecific territory intruders.We did not find any evidence that the size of these yellow patches was related to social rank or body size,but dominant males tended to have larger patches than dominant females.Additionally,patch size had a rank-specific relationship with the number of affiliative interactions that individuals engaged in.Dominant males with large patches received fewer affiliative acts from their groupmates compared to dominant males with small patches.However,subordinates with large patches tended to receive more affiliative acts from their groupmates while performing fewer affiliative acts themselves.Taken together,our results suggest that patch size reflects interindividual variation in foraging effort in this cichlid fish and offer some of the first evidence that colorful signals may shape affiliative relationships withinwildsocialgroups.展开更多
The composition of assemblages,diet and behavior of waterbird species with similar ecological features are important aspects in the functioning of aquatic ecosystems.Closely related animal species often share resource...The composition of assemblages,diet and behavior of waterbird species with similar ecological features are important aspects in the functioning of aquatic ecosystems.Closely related animal species often share resources such as space and food in ways that reduce competition,but if the diets of different species strongly overlap,interspecific competition may intensify.This analysis examined behavioral data relating to Great Egret,Little Egret,and Squacco Heron to explore their foraging efficiencies in rich aquatic habitats in an arid zone during post-breeding movements.The fieldwork was carried out in small estuaries of a Wadi on the southern coast of Oman.The frequency of interactions was the highest in Squacco Heron and the lowest in Great Egret.However,the differences in the numbers of inter-and intra-specific interactions between the 3 species were significant.Activity indices calculated for a 5-min period,i.e.,the number of interactions(interaction index)and times of flying and walking(movement index)differed among the 3 species.The number of successful attacks was the highest in Squacco Heron,while the foraging effectiveness of Great Egret and Little Egret was similar.GLM analysis showed that only the movement index was significant,as it had a positive impact on individual foraging success.Great Egret caught more fish than the other 2 heron species which,in turn,caught a greater number of smaller prey items,mostly invertebrates.This study shows that heron species in the same rich habitat employ different foraging tactics.In comparison to the other two heron species,the foraging tactics of Squacco Heron seem to be the most susceptible to competition.However,its greater mobility and using different foraging tactics,enhance its foraging success.展开更多
Patterns of variation in the size of vulture foraging groups,and their ecological causes and consequences,remain litle explored despite strong links with the carrion recycling service that this key functional group pr...Patterns of variation in the size of vulture foraging groups,and their ecological causes and consequences,remain litle explored despite strong links with the carrion recycling service that this key functional group provides.We documented the group size-frequency pattern of Andean con-dors Vultur gryphus gathered to feed on 42 equine carcasses experimentally placed in Bolivia,between 2012 and 2019,along an elevation range of 1,300-4,500 m asl.Based on the location(altitude and latitude)of the foraging groups,we examined the relationship between their size and species'population parameters(size and trend),habitat conditions,and livestock carcass availability and predictability.Condors utilized a high frequency(93%)of carcasses forming groups that ranged from 1 to 80 individuals(mean=25,median=18)and shaped a"lazy-J curve"typical pattern of size-frequency distribution whereby few groups(5,12%)were large(>55 individuals)and most(21,50%)were relatively small(<19 individuals).Group size related to altitude in that most larger groups formed at lower sites(below c.3,000 m asl),likely following an altitudinal gradient whereby larger groups are more likely to form around larger carcasses(i.e.,cattle),which are more likely to occur at lower elevations.Regardless of population size,group size could be an adaptive response of condors via local enhancement for improving individual scavenging efficiency.Many information gaps on this topic still exist,thus we provide a set of questions to address them,especially amidst the unrestricted impacts of human activities that condition vulture survival globally.展开更多
文摘It is widely accepted that the Marginal Value Theorem (MVT) describes optimal foraging strategies of animals and the mechanism proposed by the MVT has been supported by a number of field observations. However, findings of many researchers indicate that in natural conditions foragers do not always behave according to the MVT. To address this inconsistency, in a series of computer simulation experiments, we examined the behaviour of four types of foragers having specific foraging efficiencies and using the MVT strategies in 15 different landscapes in an ideal environment (no intra-and inter-specific interactions). We used data on elk (Cervus elaphus) to construct our virtual forager. Contrary to the widely accepted understanding of the MVT (residence time in a patch should be longer in environments where travel time between patches is longer) we found that in environments with the same average patch quality and varying average travel times between patches, patch residence times of some foragers are not affected by travel times. Based on our analysis we propose a mechanism responsible for this observation and formulate the perfect forager theorem (PFT). We also introduce the concepts of a foraging coefficient (F) and foragers’ hub (α), and propose a model to describe the relationship between the perfect forager and all other forager types.
文摘Lesser kestrels Falco naumanni are migratory central-place foragers that breed in dynamic arable landscapes. After arriving from migration, kestrels have no knowledge of the distribution of crops, and consequently prey, around their colony. The energy demand of pairs increases as breeding season progresses, but at the same time prey abundance, and their knowledge on prey distribution, also increases. Wind can have a strong influence on flight cost and kestrels should try to reduce energy expendi- ture when possible. When prey abundance is low, kestrels have little knowledge of prey distribution, and pairs have no chicks, they could reduce foraging flight cost by leaving the colony with tailwinds. When prey is abundant, knowledge on prey distribu- tion has increased, and chick demand is high, kestrels should fly to the most favorable foraging patches. We analyzed foraging trips directions in a lesser kestrel colony along the breeding season and in relation to wind speed and direction. We recorded 664 foraging trips from 19 individuals using GPS-dataloggers. We found that outward flights direction changed from uniform to a concentrated distribution along the season, as prey abundance and individual experience increased. We also found a temporal trend in the angular difference between outward flights and wind directions, with low values early in the season and then increa- sing as expected, but again low values at the end, contrary to expectation. Results suggest changes in kestrels foraging strategy along the season in relation to wind. Kestrels depart more with tailwinds in exploratory flights early in the season, while there is a spurious coincidence in direction to preferred foraging patches and dominant wind direction at the end [Current Zoology 60 （5）： 604-615, 2014].
文摘Artifcial light at night(ALAN)is a common anthropogenic disturbance,which alters animal behavior.However,little is known about the impact of the spectral composition of ALAN and co-occurring predation risk on the behavior of aquatic organisms.We experimentally investigated how ALAN of different spectra(cool white LED and HPS light)affects the behavior and foraging of Gammarus jazdzewskii(Amphipoda)on chironomid prey,both as a single stressor and in combination with an olfactory predation cue.Gammarids exposed to ALAN in the absence of predation cues consumed less,compared with darkness,mainly due to their lower activity.Moreover,gammarids showed a stronger response to LED light,spending more time in the shelter and increasing prey handling time in this treatment.The addition of predation cues did not enhance the negative impact of ALAN on the foraging success.Gammarids maintained similar consumption levels as in the ALAN treatment without predation cues and in darkness with predation cues.However,gammarids in LED light altered their behavior in response to predation threat:they decreased prey handling time and consumed prey faster,which may have compensated for the higher food demand in stressful conditions.They also tended to exhibit risky behavior,leaving the shelter and moving towards the lit area,presumably to escape and avoid the combined effects of light and predation cues.Therefore,when assessing the effects of ALAN on organisms,light quality and co-occurring biotic factors should be considered,as predator pressure is common in natural environments.
基金funded by the National Key R&D Program of China(2022YFD1300803)the China Agriculture Research System of MOF and MARA(CARS-34)。
文摘Grain soybean(Glycine max(L.)Merr.)shows potential as a forage crop following its introduction from low to high latitudes due to in its growth phenotype.However,the application of this approach is impeded by the diverse ecological types of soybean,their adaptability to the introduction,and the uncertainty surrounding the growth phenotype post-introduction.This study introduced 24 grain soybean varieties from low-latitude regions(22-31°N)to the high-latitude northwestern Loess Plateau(39°N)between 2018 and 2019.The growth phenotypes were observed,and their forage productivity potential was assessed.All varieties displayed delayed flowering following cross-latitude introduction,with the vegetative growth phase of some varieties even exceeding their entire growth duration at their origin.Rapid dry matter accumulation rates indicated growth adaptation performance and formed the basis for soybean forage yield.Varieties from the tropical South China region exhibited significant yield advantages,with dry matter yields of 8.97-14.68 t ha^(-1)and crude protein yields of 1.44-2.51 t ha^(-1).Varieties HX3 and GX7 from this region demonstrated optimal growth adaptability and productivity in the cross-latitude environment,achieving the highest dry matter yields of 14.68 and 13.86 t ha^(-1),respectively.As a result,HX3 and GX7 are recommended for local farming systems to provide high-quality forage.The cross-latitude introduction of soybean is proposed as a viable and efficient strategy for forage improvement and application.
文摘Two widespread bird species in Sri Lanka’s dry zone,Pycnonotus cafer(Red-vented Bulbul,RVBB)and Pycnonotus luteolus(White-browed Bulbul,WBBB),were studied to understand their foraging dynamics and ecology.The research was conducted from October 2022 to February 2023 in Mihintale Sanctuary(80.30′11.24″E,8.21′04.63″N)and the Faculty of Applied Sciences,Rajarata University of Sri Lanka(80.502206″E,8.353090″N).Data were obtained through focal sampling,opportunistic observations,and mist netting.Both species predominantly foraged on twigs,using gleaning as the dominant food-handling technique.RVBB foraged mostly at the canopy level,while WBBB foraged primarily at the sub-canopy level.Fruits constituted the major food type for both species.RVBB and WBBB utilized 10 and 7 plant species,respectively,with Grewia helicterifolia being the primary foraging plant.Minimal foraging was observed on Croton sp.(RVBB)and Hugonia mistax(WBBB).The correlation between nutritional components and the consumption of both species revealed a preference for foods with lower protein,higher fat,and ash content.There was no linear correlation between gape width and fruit size(r=-0.21,P=0.69)for both species.The standardized dietary niche breadth indicated both species are specialists,with a high pairwise dietary niche overlap(0.9854).These findings highlight the niche-specific foraging adaptations of RVBB and WBBB within Mihintale,emphasizing their distinct strategies in utilizing plant species,fruit sizes,and foraging heights.Understanding such ecological dynamics is essential for habitat conservation efforts and ensuring the availability of key foraging resources for these species in the dry zone.
基金funded by the National Natural Science Foundation of China(No.32470553).
文摘Food abundance and availability constitute fundamental determinants of foraging habitat quality for waterbirds, with high-quality foraging habitats playing a crucial role in supporting the survival and annual life cycle of wintering populations. The ongoing degradation and loss of optimal habitats have forced wintering waterbirds to increasingly rely on alternative foraging sites and modify their behavioral adaptation strategies to cope with food scarcity. The Siberian Crane (Leucogeranus leucogeranus), a large-bodied endangered waterbird species characterized by specialized dietary preferences, demonstrates particular sensitivity to environmental alterations. Faced with diminishing suitable habitats and declining natural food resources, this species has progressively adapted to utilizing artificial habitats, including agricultural landscapes such as paddy fields and lotus ponds, as supplementary wintering foraging grounds to fulfill their energetic requirements. This study examines the hypothesis that Siberian Cranes adapt their foraging behavior through plastic behavioral strategies in artificial habitats under conditions of limited food availability, thereby enhancing population fitness. A comparative analysis of crane foraging behaviors was conducted between mudflats and lotus ponds throughout the 2023–2024 wintering period. This investigation focused on three critical environmental factors: food abundance, food burial depth, and sediment penetrability, examining their influence on foraging patterns across these distinct habitats. The results revealed significant inter-habitat differences: foraging success rates were substantially higher (p < 0.05) and food handling times markedly longer in lotus ponds compared to mudflats, whereas foraging effort and attempt frequency were significantly elevated in mudflat habitats. The superior food availability in lotus ponds facilitated enhanced foraging success rates, enabling cranes to accumulate essential energy reserves for winter survival. However, the deeper burial depth of lotus roots in these habitats required more intensive processing behaviors, including prolonged digging, breaking, and swallowing activities, which consequently increased handling time by approximately 40% and reduced foraging attempts by 25–30% compared to mudflat conditions. These behavioral trade-offs suggest that while lotus ponds provide adequate food resources, their structural characteristics may impose physiological constraints that limit their effectiveness as optimal foraging grounds for Siberian Cranes. These findings offer valuable insights into the behavioral plasticity of wintering Siberian Cranes response to spatial variations in food resource distribution, while contributing to our understanding of the ecological value of lotus roots as alternative winter food sources in artificial wetland ecosystems.
文摘Understanding the fundamental drivers of large-scale species co-occurrence is a critical issue in ecology and conservation research. Here, we assessed foraging guilds, habitat type and disturbances as drivers of bird species co-occurrence in Ghana's Central Region over six months. Birds were sampled in 120 points across six different habitat types (farmland, forest reserve, urban area, coastal savannah, wetland, and mangrove), using the point-centred count technique. In total, 4060 individuals belonging to 216 species were recorded across all six habitat types. We found that co-occurring species were more similar in their foraging behaviour and habitat association. About 60% of the birds were found to co-occur randomly, 15% co-occurred negatively, and 25% co-occurred positively. Carnivores like the Black Heron (Egretta ardesiaca) and Spur-winged Lapwing (Vanellus spinosus) randomly co-occurred with other guild groups and were dominant in the mangroves and wetlands. Frugivores from forest reserves had only a 25% chance of randomly co-occurring with other birds and about a 60% chance of positively co-occurring with other birds. Our findings suggest that foraging guilds and habitat type are major factors driving bird co-occurrence and community assemblages in this West African suburban region.
基金financial and logistic support(for fieldwork campaigns,GPS tracking devices and laboratory analysis)from the project LIFE Ilhas Barreira project(LIFE18 NAT/PT/000927)funding provided by Foundation for Science and Technology,I.P.(FCT)to MARE(UIDB/MAR/04292/2020,https://doi.org/10.54499/UIDB/04292/2020 and UIDP/04292/2020,https://doi.org/10.54499/UIDP/04292/2020+1 种基金the Associate Laboratory ARNET(LA/P/0069/2020,https://doi.org/10.54499/LA/P/0069/2020)supported by FCT doctoral fellowships(10.54499/2020.07495.BD,SFRH/BD/145827/2019)。
文摘Little Terns Sternula albifrons are estuarine birds extensively using increasingly urbanized coastal areas.Given the increased exposure of these ecosystems to anthropogenic activities,it is crucial to study the ecology of this species and interactions with human stressors to establish management measures.We collected regurgitates(n=182)and blood samples(n=48)to study Little Terns’diet,health condition and isotopic niche,and individually tracked breeding adults(n=9,during 2021 and 2022)at 2 sandy beaches 21 km apart and located within Ria Formosa Natural Park,Algarve,Portugal.Although both areas are adjacent to foraging coastal marine areas and an estuarine lagoon system with saltpans,they differ in human disturbance.We also compared breeding success and adult health measures between these 2 colonies.The main prey for both populations were Sand Smelts Atherina spp.and Gobies Pomatoschistus spp.,and no differences in δ^(13)C and δ^(15)N stable isotopic values between colonies were found.Tracking data revealed that individuals foraged in the surroundings of their breeding colonies.Entrance Channels and Ocean were the most frequently used habitats for foraging by individuals from the less disturbed colony.Adults from the more disturbed colony foraged mostly in Entrance Channels.Overall,all individuals tended to forage during daytime.There were no differences in health measures of individuals between colonies,though breeding success at the most disturbed colony was comparably lower.It is important to protect both breeding areas and adjacent foraging habitats for Little Terns,particularly given the expected increasing pressure from human activities on coastal areas worldwide.
文摘Next-generation 6G networks seek to provide ultra-reliable and low-latency communications,necessitating network designs that are intelligent and adaptable.Network slicing has developed as an effective option for resource separation and service-level differentiation inside virtualized infrastructures.Nonetheless,sustaining elevated Quality of Service(QoS)in dynamic,resource-limited systems poses significant hurdles.This study introduces an innovative packet-based proactive end-to-end(ETE)resource management system that facilitates network slicing with improved resilience and proactivity.To get around the drawbacks of conventional reactive systems,we develop a cost-efficient slice provisioning architecture that takes into account limits on radio,processing,and transmission resources.The optimization issue is non-convex,NP-hard,and requires online resolution in a dynamic setting.We offer a hybrid solution that integrates an advanced Deep Reinforcement Learning(DRL)methodology with an Improved Manta-Ray Foraging Optimization(ImpMRFO)algorithm.The ImpMRFO utilizes Chebyshev chaotic mapping for the formation of a varied starting population and incorporates Lévy flight-based stochastic movement to avert premature convergence,hence facilitating improved exploration-exploitation trade-offs.The DRL model perpetually acquires optimum provisioning strategies via agent-environment interactions,whereas the ImpMRFO enhances policy performance for effective slice provisioning.The solution,developed in Python,is evaluated across several 6G slicing scenarios that include varied QoS profiles and traffic requirements.The DRL model perpetually acquires optimum provisioning methods via agent-environment interactions,while the ImpMRFO enhances policy performance for effective slice provisioning.The solution,developed in Python,is evaluated across several 6G slicing scenarios that include varied QoS profiles and traffic requirements.Experimental findings reveal that the proactive ETE system outperforms DRL models and non-resilient provisioning techniques.Our technique increases PSSRr,decreases average latency,and optimizes resource use.These results demonstrate that the hybrid architecture for robust,real-time,and scalable slice management in future 6G networks is feasible.
基金funded by the National Natural Science Foundation of China(No.42361144873)Yellow Sea Wetland Project(No.HHSDKT202312)the“Saving Spoon-billed Sandpiper”project of Shenzhen Mangrove Wetlands Conservation Foundation(MCF)。
文摘Abundant food supply is crucial for the survival of long-distance migratory birds.The continued population decline of the Spoon-billed Sandpiper(Calidris pygmeae),a critically endangered shorebird,is primarily attributed to habitat loss and degradation.However,significant gaps remain in research on their diet and foraging habitat selection,limiting effective conservation and restoration efforts.In this study,we investigated the composition of macrobenthic communities,analyzing habitat and prey selection at the main foraging area of SBS in Tiaozini,Jiangsu Province of eastern China—their most critical staging site during southward migration.Our findings revealed 25 species of macrobenthos in foraging areas,with mobile epibenthos comprising the largest group by biomass,accounting for 73%,and having higher density and biomass nearshore.Observations of foraging Spoon-billed Sandpiper individuals indicated that shallow water habitats were their preferred foraging environments,where mobile epibenthos,which thrive in these habitats after the tide recedes,made up 81%of their biomass intake.We propose that shallow water habitats in intertidal mudflats serve as essential refuges for mobile epibenthos after tidal retreat,thereby providing Spoon-billed Sandpipers with access to high-quality food resources.Habitat protection efforts should prioritize habitats harboring extensive microhabitats with shallow water,especially the nearshore area,and further research is needed to explore the mechanisms underlying the formation of these microhabitats,with the ultimate goal of restoring more high-quality habitats for the Spoonbilled Sandpiper.
文摘The authors regret that the scientific names of some species mentioned in the paper were incorrectly presented.The incorrect sci-entific names,their locations in the paper,correct spellings and refer-ences,are listed below.
基金supported by the National Research Foundation of Korea(NRF)grant funded by the Korea government(MSIT)(No.2021R1A2C201017812)support of‘R&D Program for Forest Science Technology(Project No.2022461B10-2424-0201)’provided by Korea Forest Service(Korea Forestry Promotion Institute)。
文摘Mammal distribution is shaped by different ecological and anthropogenic factors,and the pattern varies depending on their sensitivity thresholds,food and habitat preferences,ecological roles,and physical traits.The present study investigated the influence of ecological and anthropogenic factors on the distribution of mammal species communities across different trophic levels and body sizes in Myanmar's Htamanthi Wildlife Sanctuary(HWS).The values of mammal characteristics,ecological,and anthropogenic factors were analyzed in ArcMap software.Most of the large and small sized mammals,whose distribution decreases with elevation,were observed near the main streams.Across mammal tropic levels,the omnivores and herbivores were mostly observed farther from gold mining sites.In terms of forage plant effect on mammal community,floral forage plants and the presence of climber negatively affected mammal species across different trophic levels.Moreover,presence of resin trees also has a substantial impact on the distribution of medium-large animals and omnivorous mammals as trophic niche factors.Overall,our findings highlight the crucial role that ecological and anthropogenic factors play in shaping mammal distribution in the HWS.This underscores the importance of simultaneously conserving both habitat and mammal diversity in HWS,especially in the face of a changing climate and environment.
基金funded by the China Agriculture Research System of MOF and MARA (CARS-34)the National Natural Science Foundation of China (32201471)+1 种基金the Development and Demonstration Project of Key Technologies for High Quality Development of Forage Industry in Ordos, Chinathe fellowship of China Postdoctoral Science Foundation (2023T160697)。
文摘The “Greater Food” approach has replaced the older “taking grain production as a top priority” approach. Theimportance of feed and forage as the material basis for guaranteeing high-quality development of the livestock industry has gradually become prominent. However, owing to the tradition of “both human staple food and animal feed relying on grain production” in China and the decoupling of feed crop planting and livestock farming, the risk of feed grain security has increased, especially as it relates to the supply of high-quality protein feed ingredients from abroad, which is facing a bottleneck. To ensure food security, effective domestic agricultural production should be adopted. Nevertheless, guaranteeing the supply of high-quality protein feed through domestic soybean production is difficult because of limited arable land;furthermore, pressure on the staple food supply is still extreme. In this article, the historical and realistic implications for the security risks of feed grain in China are analyzed. Proposals are made to separate staple food grains for humans from the feed grain supply for animals and to develop high-quality forage to reduce feed grain use. High-quality forage can be supplied via intercropping with grain crops in arable land and reseeding perennial legumes or grasses into natural grasslands. However, “managing forage for grain” needs to be supported via technical paths and policies as the forage industry develops to effectively increase the capacity to ensure feed grain security.
文摘Social learning is a mechanism used by many species to effciently gain information about their environment.Although many animals live in an environment where members of other species are present,little is known about interspecifc social learning.Domesticated and urbanized species provide the opportunity to investigate whether nonhuman animals can learn from heterospecifcs such as humans,who are integral parts of their social landscape.Although domestic dogs Canis familiaris have been intensively researched for their ability to learn from humans,most studies have focused on dogs living as pets.However,free-ranging dogs represent the majority of the world’s dog population,they live alongside humans,scavenge on human refuse,and are subject to natural and sexual selection.Thus,free-ranging dogs with extensive exposure to humans and their artifacts provide the opportunity to investigate interspecifc social learning in a naturalistic setting,where learning from humans might be a beneft for them.Here we tested individual free-ranging dogs in a between-subject design:Dogs in the control group could spontaneously choose between two novel and differently patterned food-delivering boxes.In the experimental group,instead,dogs could frst observe an unfamiliar human approaching and eating from 1 of the 2 boxes.We provide the frst evidence that free-ranging dogs match the choice of an unfamiliar human.These results show that at least simple forms of interspecifc social learning might be involved in dogs’success in living alongside humans in a complex urbanized environment.
文摘This paper comprehensively analyzes the Manta Ray Foraging Optimization(MRFO)algorithm and its integration into diverse academic fields.Introduced in 2020,the MRFO stands as a novel metaheuristic algorithm,drawing inspiration from manta rays’unique foraging behaviors—specifically cyclone,chain,and somersault foraging.These biologically inspired strategies allow for effective solutions to intricate physical challenges.With its potent exploitation and exploration capabilities,MRFO has emerged as a promising solution for complex optimization problems.Its utility and benefits have found traction in numerous academic sectors.Since its inception in 2020,a plethora of MRFO-based research has been featured in esteemed international journals such as IEEE,Wiley,Elsevier,Springer,MDPI,Hindawi,and Taylor&Francis,as well as at international conference proceedings.This paper consolidates the available literature on MRFO applications,covering various adaptations like hybridized,improved,and other MRFO variants,alongside optimization challenges.Research trends indicate that 12%,31%,8%,and 49%of MRFO studies are distributed across these four categories respectively.
基金funded by the National Natural Science Foundation of China(Grant No.32360142).
文摘Extreme droughts are increasing in frequency and severity globally as a result of climate change.Developing understanding of species’responses to drought is crucial for their conservation,especially in regions experi-encing increased aridity.Although numerous studies have investigated birds’responses to drought,the emphasis has primarily been on landbirds.Drought can significantly alter the wetland environments that waterbirds inhabit,but the response of waterbirds to drought remains understudied.In this study,we surveyed the distri-bution and behavior of Oriental Storks(Ciconia boyciana)in Poyang Lake,which is the largest freshwater lake in China.Results indicate that drought-induced catchment areas at the lowest water level limited the total popu-lation size of Oriental Storks in the sub-lakes.Sub-lakes with large catchment areas at the lowest water level demonstrated a capacity to support a larger population of wintering Oriental Storks.Over time,Oriental Storks exhibited a gradual concentration in Changhu Lake,characterized by larger catchments,after resource depletion in sub-lakes with smaller catchments.Additionally,the duration of Oriental Storks’vigilance and moving be-haviors decreased significantly compared with that observed before the drought.After the drought,Oriental Storks increased their foraging efforts,as evidenced by increased presence in deeper water and reaching their heads and necks into deeper water to forage,higher search rates,but lower foraging rates.In accordance with area-restricted search theory,reductions in habitat quality resulting from drought,including extensive fish die-offs,forced Oriental Storks to increase their foraging efforts.Sustaining a specific water area in sub-lakes during droughts can preserve resource availability,which is crucial for the conservation of Oriental Storks.Imple-menting measures such as water level control and micro-modification of lake bottoms in sub-lakes might mitigate the impact of drought on the piscivorous Oriental Storks.
文摘Recent advances in our understanding of avian chemical communication have highlighted the importance of olfaction in many aspects of avian life.Prior studies investigating predator avoidance behaviors in response to predator odor cues have produced mixed results across species and contexts.Here we assess if a community of birds in eastern Pennsylvania displays avoidance behaviors towards predator odor cues in a natural foraging setting.We use clay caterpillars to measure foraging activity by birds in the presence of predator(bobcat)urine,non-predator(rabbit)urine,and water controls in two different environmental contexts(field vs.forest).Although we detected a weak trend for birds to forage less at predator urine-treated sites,we found no significant difference in avian foraging between the site types.We did find that foraging rates between environmental contexts changed significantly over the course of the experiment,with forest sites showing decreasing foraging rates and field sites showing increasing foraging rates.Our results reinforce the published literature that avoidance of predator odors by birds may not be ubiquitous across contexts and species.
基金supported by a Natural Sciences and Engineering Research Council of Canada(NSERC)Discovery grant provided to SB(RGPIN-2016-05772)the National Science Foundation under grant No.1557836 provided to IMH.
文摘Many animals use color to signal their quality and/or behavioral motivations.Colorful signals have been well studied in the contexts of competi-tion and mate choice;however,the role of these signals in nonsexual,affiliative relationships is not as well understood.Here,we used wild social groups of the cichlid fish Neolamprologus pulcher to investigate whether the size of a brightly colored facial patch was related to 1)individual quality,2)social dominance,and/or 3)affiliative relationships.Individuals with larger patches spent more time foraging and tended to perform more aggressive acts against conspecific territory intruders.We did not find any evidence that the size of these yellow patches was related to social rank or body size,but dominant males tended to have larger patches than dominant females.Additionally,patch size had a rank-specific relationship with the number of affiliative interactions that individuals engaged in.Dominant males with large patches received fewer affiliative acts from their groupmates compared to dominant males with small patches.However,subordinates with large patches tended to receive more affiliative acts from their groupmates while performing fewer affiliative acts themselves.Taken together,our results suggest that patch size reflects interindividual variation in foraging effort in this cichlid fish and offer some of the first evidence that colorful signals may shape affiliative relationships withinwildsocialgroups.
基金supported by the University of Siedlce,Poland(Theme No.151/23/B and 152/23/B fnanced from a science grant by the Ministry of Education and Science,Poland).
文摘The composition of assemblages,diet and behavior of waterbird species with similar ecological features are important aspects in the functioning of aquatic ecosystems.Closely related animal species often share resources such as space and food in ways that reduce competition,but if the diets of different species strongly overlap,interspecific competition may intensify.This analysis examined behavioral data relating to Great Egret,Little Egret,and Squacco Heron to explore their foraging efficiencies in rich aquatic habitats in an arid zone during post-breeding movements.The fieldwork was carried out in small estuaries of a Wadi on the southern coast of Oman.The frequency of interactions was the highest in Squacco Heron and the lowest in Great Egret.However,the differences in the numbers of inter-and intra-specific interactions between the 3 species were significant.Activity indices calculated for a 5-min period,i.e.,the number of interactions(interaction index)and times of flying and walking(movement index)differed among the 3 species.The number of successful attacks was the highest in Squacco Heron,while the foraging effectiveness of Great Egret and Little Egret was similar.GLM analysis showed that only the movement index was significant,as it had a positive impact on individual foraging success.Great Egret caught more fish than the other 2 heron species which,in turn,caught a greater number of smaller prey items,mostly invertebrates.This study shows that heron species in the same rich habitat employ different foraging tactics.In comparison to the other two heron species,the foraging tactics of Squacco Heron seem to be the most susceptible to competition.However,its greater mobility and using different foraging tactics,enhance its foraging success.
基金funded by The Peregrine Fund's Neotropical Science and Student Education Program,a British Ornithologists'Union Small Ornithological Research Grant,a Neotropical Birding and Conservation(formerly known as Neotropical Bird Club)Conservation Award granted to D.Méndez in 2014,and two 2018 grants to D.Méndez,one from the Rufford Small Grants Foundation(24763-1)another from the International Foundation for Science(I-1-D-6156-1).
文摘Patterns of variation in the size of vulture foraging groups,and their ecological causes and consequences,remain litle explored despite strong links with the carrion recycling service that this key functional group provides.We documented the group size-frequency pattern of Andean con-dors Vultur gryphus gathered to feed on 42 equine carcasses experimentally placed in Bolivia,between 2012 and 2019,along an elevation range of 1,300-4,500 m asl.Based on the location(altitude and latitude)of the foraging groups,we examined the relationship between their size and species'population parameters(size and trend),habitat conditions,and livestock carcass availability and predictability.Condors utilized a high frequency(93%)of carcasses forming groups that ranged from 1 to 80 individuals(mean=25,median=18)and shaped a"lazy-J curve"typical pattern of size-frequency distribution whereby few groups(5,12%)were large(>55 individuals)and most(21,50%)were relatively small(<19 individuals).Group size related to altitude in that most larger groups formed at lower sites(below c.3,000 m asl),likely following an altitudinal gradient whereby larger groups are more likely to form around larger carcasses(i.e.,cattle),which are more likely to occur at lower elevations.Regardless of population size,group size could be an adaptive response of condors via local enhancement for improving individual scavenging efficiency.Many information gaps on this topic still exist,thus we provide a set of questions to address them,especially amidst the unrestricted impacts of human activities that condition vulture survival globally.
