| Flight initiation distance(FID)is defined as the distance at which an animal flees due to the presence of an approaching stimulus(such as predator or human being).It can reflect the trade-off between the benefits acquired by current activity and the costs of fleeing,and give an indication of ability to coexist with human.Human disturbance can affect the behavior and reproductive success of birds.To successfully inhabit urban environments,birds must cope with the high level of human disturbance.Common Magpie(Pica pica)and Azure-winged Magpie(Cyanopica cyanus)are extremely successful urban adapters,and can be found in high densities in urban parks,also occurring in farm land and woodland in exurban areas.Thus,they are good species that suit for understanding the characteristics of species that have adapted to urbanization and the changes in changes in behavior,physiology,and life history.However,special and temporal variation in human disturbance exist in nature,and understanding how birds successfully adaptation to this variation can contribute to understand how bird behavior changes in response to urbanization.The object of this study was to investigate how Common Magpie and Azure-winged Magpie adapt to human disturbance using FID.More specifically,(1)whether variation of human disturbance during a short period affect Common Magpie and Azure-winged Magpie FIDs.(2)whether Common Magpie and Azure-winged Magpie FIDs different between winter and spring.(3)whether direction of approach affect Common Magpie and Azure-winged Magpie FIDs along gradients of human disturbance.(4)whether Common Magpie and Azure-winged Magpie alert distance(the distance between a prey and an approaching predator when the prey responds overtly to the predator by change of posture or orientation to monitor the predator)and buffer distance(alert distance minus flight initiation distance)different along gradients of human disturbance.This study was performed in thirteen parks in Beijing from December 15,2015,to July 15,2016.The main results showed that:(1)Pedestrian rate was significant different between weekdays and weekends,with more visitors in the weekdays than in the weekends(F1,139=79.704,P<0.001).However,there was no significant difference in FIDs between weekdays and weekends(Common Magpie:F1,186=0.997,P=0.319;Azure-winged Magpie:F1,96=0.385,P=0.536).(2)Pedestrian rate was significant different between winter and spring,with more visitors in the spring than in the winter(F1,152=58.065,P<0.001).However,there was no significant difference in FIDs between winter and spring(Common Magpie:F1,184=0.034,P=0.854;Azure-winged Magpie:F1,113=0.152,P=0.698).(3)FIDs were decreased significantly with human disturbance(Common Magpie:F1,250=79.162,P<0.001;Azure-winged Magpie:F1,169=62.517,P<0.001).Moreover,FIDs were shorter for tangential approach in high human disturbance(Common Magpie:F1,142=8.720,P=0.004;Azure-winged Magpie:F1,120=6.647,P=0.011),but was not in low human disturbance(Common Magpie:F1,103=1.5954,P=0.209;Azure-winged Magpie:F1,44=0.125,P=0.725).(4)Alert distances were decreased significantly with human disturbance(Common Magpie:F1,127=25.016,P<0.001;Azure-winged Magpie:F1,79=37.784,P<0.001).However,buffer distances were not affected by human disturbance(Common Magpie:F1,128=0.096,P=0.758;Azure-winged Magpie:F1,80=0.091,P=0.565).Using human approach,we studied the effect of human disturbance on Common Magpie and Azure-winged Magpie antipredator behavior.FID was not changed during short and long period,meaning that it is a good indicator of tolerance.Moreover,Common Magpie and Azure-winged Magpie lived in urban habitats not only are more tolerant to human disturbance,but also can change their escape behavior based on human approach direction,these traits possibly representing an adaptation to living in urban areas. |
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