This study assessed the nesting patterns of raptors, Gyps africanus and Haliaeetus vocifer in Lochinvar National Park. The main objective of the study was to determine whether tree species, height, girth size, and hab...This study assessed the nesting patterns of raptors, Gyps africanus and Haliaeetus vocifer in Lochinvar National Park. The main objective of the study was to determine whether tree species, height, girth size, and habitat influenced raptor’s nest placement within Lochinvar National Park. Two species were selected as indicator species for the raptors. Habitat types and tree species were identified and measurements of tree species with nests measured. It was found that the minimum height of nest placement was 10 meters above ground and Acacia woodland was found to be the most preferred habitat for nest placement. Raptors avoided human disturbance by placing their nests at least 100 meters away from human disturbance and from the National park boundary inwards or abandoning if human encroachment comes close to the nest. More research is required to assess nesting materials used, and to determine whether raptors can swap nets or return to the abandoned nests when human disturbance ceases.展开更多
Background:Power lines are amongst the main causes of mortality for birds globally.Electrocution drives the population dynamics of several threatened species of raptors,at local and global scales.Among the many soluti...Background:Power lines are amongst the main causes of mortality for birds globally.Electrocution drives the population dynamics of several threatened species of raptors,at local and global scales.Among the many solutions that have been tested to minimize this threat are supplemental perches;however,their efficiency has rarely been assessed.Methods:We designed 43 transects in 4 districts in mainland Portugal to gather data from birds perching on pylons with or without supplemental perches.From 2015 to 2018,transects were surveyed by car at least once.We analyzed the factors driving the use of these supplemental perches,and we analyzed if there were differences in the perceived risk(calculated from measurements and not from field surveys)depending on whether the perching was on pylons with or without supplemental perches.Results:We recorded 548 perches of 14 species.Weather conditions seemed to play a role in birds’choice of pylons with supplemental perches versus pylons without supplemental perches.Models also indicated a strong influence of observational conditions.The use of models showed us an important specific effect in the selection of supplemental perches where available:there are some species with a greater tendency to perch on supplemental perches,even when they use both pylons with and without supplemental perches.For most of the analyzed species and species groups,perceived risk was higher in pylons without supplemental perches compared to pylons with supplemental perches,but there were differences between species.Conclusions:Supplemental perches may be a useful and efficient tool for mitigating raptor electrocution.However,there are many influential factors affecting their success,and their effectiveness with different species groups is not homogeneous.Some studies show higher electrocution rates for certain species and devices and thus,their efficacy must be validated.We propose a two-step validation process,first in controlled conditions and then in the field.A common protocol should be established to enable comparisons between studies.展开更多
Raptors are getting more attention from researchers because of their excellent flight abilities.And the excellent wing morphing ability is critical for raptors to achieve high maneuvering flight,which can be a good bi...Raptors are getting more attention from researchers because of their excellent flight abilities.And the excellent wing morphing ability is critical for raptors to achieve high maneuvering flight,which can be a good bionic inspiration for unmanned aerial vehicles(UAV)design.However,morphing wing motions of Falco peregrinus with multi postures cannot be consulted since such a motion database was nonexistent.This study aimed to provide data reference for future research in wing morphing kinetics.We used the computed tomography(CT)approach to obtain nine critical postures of the Falco peregrinus wing skeleton,followed with motion analysis of each joint and bone.Based on the obtained motion database,a six-bar kinematic model was proposed to regenerate wing motions with a high fidelity.展开更多
Raptors can change the shape and area of their wings to an exceptional degree in a fast and efficient manner,surpassing other birds,insects,or bats.Some researchers have focused on the functional properties of muscle ...Raptors can change the shape and area of their wings to an exceptional degree in a fast and efficient manner,surpassing other birds,insects,or bats.Some researchers have focused on the functional properties of muscle skeletons,mechanics,and flapping robot design.However,the wing motion of the birds of prey has not been measured quantitatively,and synthetic bionic wings with morphing abilities similar to raptors are far from reality.Therefore,in the current study,a 3D suspension system for holding bird carcasses was designed and fabricated to fasten the wings of Falco Peregrinus with a series of morphing postures.Subsequently,the wing skeleton of the falcon was scanned during extending motions using the computed tomography(CT)approach to obtain three consecutive poses.Subsequently,the skeleton was reconstructed to identify the contribution of the forelimb bones to the extending/folding motions.Inspired by these findings,we propose a simple mechanical model with four bones to form a wing-morphing mechanism using the proposed pose optimisation method.Finally,a bionic wing mechanism was implemented to imitate the motion of the falcon wing—divided into inner and outer wings with folding and twisting motions.The results show that the proposed four-bar mechanism can track bone motion paths with high fidelity.展开更多
Raptors primarily use soaring-gliding flight which exploits thermals and ridge lifts over land to reduce energetic costs However during migration, these birds often have to cross water surfaces where thermal currents ...Raptors primarily use soaring-gliding flight which exploits thermals and ridge lifts over land to reduce energetic costs However during migration, these birds often have to cross water surfaces where thermal currents are weak; during these times, birds mainly use flapping （powered） flight which increases energy consumption and mortality risk. As a result, some species have evolved strategies to reduce the amount of time spent over water by taking extensive detours over land. In this paper, we con- ducted a meta-analysis of water-crossing tendencies in Afro-Palearctic migrating raptors in relation to their morphology, their flight performance, and their phylogenetic relationships. In particular, we considered the aspect ratio （calculated as the wing span squared divided by wing area）, the energetic cost of powered flight, and the maximum water crossing length regularly performed by adult birds. Our results suggest that energy consumption during powered flight predominately affects the ability of raptors to fly over water surfaces展开更多
Inland wetlands in Abu Dhabi Emirate are wintering and stopover sites for migratory birds of prey. We conducted long-term regular monitoring surveys in Al Wathba Wetland Reserve (AWWR) from January 1995 to December 20...Inland wetlands in Abu Dhabi Emirate are wintering and stopover sites for migratory birds of prey. We conducted long-term regular monitoring surveys in Al Wathba Wetland Reserve (AWWR) from January 1995 to December 2022. Both diurnal and occasionally nocturnal surveys were undertaken to record the migratory raptors and owls in the Wetland Reserve. During the study, a total of 1282 regular monitoring visits were undertaken and 27 species of diurnal raptors and owls representing five families and three orders were detected. These represent 57% of the total species of birds of prey recorded in the UAE. Overall, 63% of all the species that we observed were Accipitriformes followed by 26% Falconiformes and 11% Strigiformes. We found that changes in mean daily temperature have a positive effect on raptor species diversity and abundance in the Wetland Reserve. The species encounter rate was higher in low temperature as compared to high temperature and overall regression equation was statistically significant F (4, 1126) = 8.49), p = 0.00). However, the numbers of raptors did not vary significantly across the years (p = 0.51). Western Marsh-harrier (Circus aeruginosus) and Greater Spotted Eagle (Clanga clanga) were recorded to be the most abundant species in the wetland reserve followed by Common Kestrel (Falco tinnunculus). However, the encounter rate of globally threatened Greater Spotted Eagle was detected to have significantly decreased since 2016. Moreover, 63% of the species detected were uncommon and rarely recorded such as 1) Saker Falcon 2) Lanner Falcon 3) Long-eared Owl & Merlin, which were the rare records from the wetland reserve. Furthermore, 27 years of regular monitoring in the wetland have yielded diverse diurnal raptors and owl fauna (H) = 0.83, (E) = 1.43 (Shannon Diversity Index). The results demonstrate that long-term monitoring surveys in arid environments are essential to determine the trends in the raptor populations and to document rare and globally important species.展开更多
Following a series of surveys since 2003, a full-seasonal raptor count was undertaken at Baiwangshan, a mountain in the vicinity of Beijing, from 6 March to 22 May 2009, when 3802 individual birds of 23 species were r...Following a series of surveys since 2003, a full-seasonal raptor count was undertaken at Baiwangshan, a mountain in the vicinity of Beijing, from 6 March to 22 May 2009, when 3802 individual birds of 23 species were recorded. Four species, i.e., Oriental Honey Buzzard(Pernis ptilorhynchus), Common Buzzard(Buteo buteo), Eurasian Sparrow Hawk(Accipiter nisus) and Gray-faced Buzzard(Butastur indicus) together accounted for up 90% of the total and P. ptilorhynchus alone for 70%. Raptor passage of such magnitude and diversity at an inland site in China was unheard of up to then. As well, 113 other migrants were recorded at the site during this period, including 24 water birds, 74 passerines and 15 others(cuckoos, owls and other migrants).展开更多
为了在信道带宽受限的情况下保证视频效果,提出一种适用于无线网络中视频广播通信的应用层前向纠错方案,该方案根据不同的视频符号对接收端重建视频质量的贡献为其分配不同的优先级,充分利用了视频数据的不等重要性的特点.在系统信道带...为了在信道带宽受限的情况下保证视频效果,提出一种适用于无线网络中视频广播通信的应用层前向纠错方案,该方案根据不同的视频符号对接收端重建视频质量的贡献为其分配不同的优先级,充分利用了视频数据的不等重要性的特点.在系统信道带宽有限的情况下,综合考虑了不同终端的信道状况,通过牺牲少部分低丢包率终端的视频质量为代价,获得了小区内所有用户总体接收视频质量显著提高.仿真实验结果表明:与等差错保护方案和扩展窗不等差错保护方案相比,本文提出方案的用户平均接收视频质量高2~5 d B.展开更多
文摘This study assessed the nesting patterns of raptors, Gyps africanus and Haliaeetus vocifer in Lochinvar National Park. The main objective of the study was to determine whether tree species, height, girth size, and habitat influenced raptor’s nest placement within Lochinvar National Park. Two species were selected as indicator species for the raptors. Habitat types and tree species were identified and measurements of tree species with nests measured. It was found that the minimum height of nest placement was 10 meters above ground and Acacia woodland was found to be the most preferred habitat for nest placement. Raptors avoided human disturbance by placing their nests at least 100 meters away from human disturbance and from the National park boundary inwards or abandoning if human encroachment comes close to the nest. More research is required to assess nesting materials used, and to determine whether raptors can swap nets or return to the abandoned nests when human disturbance ceases.
基金the LIFE+Nature project“Conservation of the Spanish Imperial Eagle(Aquila adalberti)in Portugal”-LIFE13 NAT/PT/001300,supported 75%by the Life Programme-European Commission。
文摘Background:Power lines are amongst the main causes of mortality for birds globally.Electrocution drives the population dynamics of several threatened species of raptors,at local and global scales.Among the many solutions that have been tested to minimize this threat are supplemental perches;however,their efficiency has rarely been assessed.Methods:We designed 43 transects in 4 districts in mainland Portugal to gather data from birds perching on pylons with or without supplemental perches.From 2015 to 2018,transects were surveyed by car at least once.We analyzed the factors driving the use of these supplemental perches,and we analyzed if there were differences in the perceived risk(calculated from measurements and not from field surveys)depending on whether the perching was on pylons with or without supplemental perches.Results:We recorded 548 perches of 14 species.Weather conditions seemed to play a role in birds’choice of pylons with supplemental perches versus pylons without supplemental perches.Models also indicated a strong influence of observational conditions.The use of models showed us an important specific effect in the selection of supplemental perches where available:there are some species with a greater tendency to perch on supplemental perches,even when they use both pylons with and without supplemental perches.For most of the analyzed species and species groups,perceived risk was higher in pylons without supplemental perches compared to pylons with supplemental perches,but there were differences between species.Conclusions:Supplemental perches may be a useful and efficient tool for mitigating raptor electrocution.However,there are many influential factors affecting their success,and their effectiveness with different species groups is not homogeneous.Some studies show higher electrocution rates for certain species and devices and thus,their efficacy must be validated.We propose a two-step validation process,first in controlled conditions and then in the field.A common protocol should be established to enable comparisons between studies.
基金supported by the National Natural Science Foundation of China(Grant Nos.52175279,52075489,and 51705459)the Natural Science Foundation of Zhejiang Province,China(Grant Nos.LY20E050022 and LGG20E050017)。
文摘Raptors are getting more attention from researchers because of their excellent flight abilities.And the excellent wing morphing ability is critical for raptors to achieve high maneuvering flight,which can be a good bionic inspiration for unmanned aerial vehicles(UAV)design.However,morphing wing motions of Falco peregrinus with multi postures cannot be consulted since such a motion database was nonexistent.This study aimed to provide data reference for future research in wing morphing kinetics.We used the computed tomography(CT)approach to obtain nine critical postures of the Falco peregrinus wing skeleton,followed with motion analysis of each joint and bone.Based on the obtained motion database,a six-bar kinematic model was proposed to regenerate wing motions with a high fidelity.
基金supported by National Natural Science Foundation of China(52175279,51705459)Natural Science Foundation of Zhejiang Province(LY20E050022).
文摘Raptors can change the shape and area of their wings to an exceptional degree in a fast and efficient manner,surpassing other birds,insects,or bats.Some researchers have focused on the functional properties of muscle skeletons,mechanics,and flapping robot design.However,the wing motion of the birds of prey has not been measured quantitatively,and synthetic bionic wings with morphing abilities similar to raptors are far from reality.Therefore,in the current study,a 3D suspension system for holding bird carcasses was designed and fabricated to fasten the wings of Falco Peregrinus with a series of morphing postures.Subsequently,the wing skeleton of the falcon was scanned during extending motions using the computed tomography(CT)approach to obtain three consecutive poses.Subsequently,the skeleton was reconstructed to identify the contribution of the forelimb bones to the extending/folding motions.Inspired by these findings,we propose a simple mechanical model with four bones to form a wing-morphing mechanism using the proposed pose optimisation method.Finally,a bionic wing mechanism was implemented to imitate the motion of the falcon wing—divided into inner and outer wings with folding and twisting motions.The results show that the proposed four-bar mechanism can track bone motion paths with high fidelity.
文摘Raptors primarily use soaring-gliding flight which exploits thermals and ridge lifts over land to reduce energetic costs However during migration, these birds often have to cross water surfaces where thermal currents are weak; during these times, birds mainly use flapping （powered） flight which increases energy consumption and mortality risk. As a result, some species have evolved strategies to reduce the amount of time spent over water by taking extensive detours over land. In this paper, we con- ducted a meta-analysis of water-crossing tendencies in Afro-Palearctic migrating raptors in relation to their morphology, their flight performance, and their phylogenetic relationships. In particular, we considered the aspect ratio （calculated as the wing span squared divided by wing area）, the energetic cost of powered flight, and the maximum water crossing length regularly performed by adult birds. Our results suggest that energy consumption during powered flight predominately affects the ability of raptors to fly over water surfaces
文摘Inland wetlands in Abu Dhabi Emirate are wintering and stopover sites for migratory birds of prey. We conducted long-term regular monitoring surveys in Al Wathba Wetland Reserve (AWWR) from January 1995 to December 2022. Both diurnal and occasionally nocturnal surveys were undertaken to record the migratory raptors and owls in the Wetland Reserve. During the study, a total of 1282 regular monitoring visits were undertaken and 27 species of diurnal raptors and owls representing five families and three orders were detected. These represent 57% of the total species of birds of prey recorded in the UAE. Overall, 63% of all the species that we observed were Accipitriformes followed by 26% Falconiformes and 11% Strigiformes. We found that changes in mean daily temperature have a positive effect on raptor species diversity and abundance in the Wetland Reserve. The species encounter rate was higher in low temperature as compared to high temperature and overall regression equation was statistically significant F (4, 1126) = 8.49), p = 0.00). However, the numbers of raptors did not vary significantly across the years (p = 0.51). Western Marsh-harrier (Circus aeruginosus) and Greater Spotted Eagle (Clanga clanga) were recorded to be the most abundant species in the wetland reserve followed by Common Kestrel (Falco tinnunculus). However, the encounter rate of globally threatened Greater Spotted Eagle was detected to have significantly decreased since 2016. Moreover, 63% of the species detected were uncommon and rarely recorded such as 1) Saker Falcon 2) Lanner Falcon 3) Long-eared Owl & Merlin, which were the rare records from the wetland reserve. Furthermore, 27 years of regular monitoring in the wetland have yielded diverse diurnal raptors and owl fauna (H) = 0.83, (E) = 1.43 (Shannon Diversity Index). The results demonstrate that long-term monitoring surveys in arid environments are essential to determine the trends in the raptor populations and to document rare and globally important species.
文摘Following a series of surveys since 2003, a full-seasonal raptor count was undertaken at Baiwangshan, a mountain in the vicinity of Beijing, from 6 March to 22 May 2009, when 3802 individual birds of 23 species were recorded. Four species, i.e., Oriental Honey Buzzard(Pernis ptilorhynchus), Common Buzzard(Buteo buteo), Eurasian Sparrow Hawk(Accipiter nisus) and Gray-faced Buzzard(Butastur indicus) together accounted for up 90% of the total and P. ptilorhynchus alone for 70%. Raptor passage of such magnitude and diversity at an inland site in China was unheard of up to then. As well, 113 other migrants were recorded at the site during this period, including 24 water birds, 74 passerines and 15 others(cuckoos, owls and other migrants).
文摘为了在信道带宽受限的情况下保证视频效果,提出一种适用于无线网络中视频广播通信的应用层前向纠错方案,该方案根据不同的视频符号对接收端重建视频质量的贡献为其分配不同的优先级,充分利用了视频数据的不等重要性的特点.在系统信道带宽有限的情况下,综合考虑了不同终端的信道状况,通过牺牲少部分低丢包率终端的视频质量为代价,获得了小区内所有用户总体接收视频质量显著提高.仿真实验结果表明:与等差错保护方案和扩展窗不等差错保护方案相比,本文提出方案的用户平均接收视频质量高2~5 d B.
