Behavioral Strategy Adjustments Of Wintering Geese As Responses To Foraging Habitat Shift

As the wetland degradations of middle and lower reaches of the Yangtze River floodplain due to the intense human disturbance,a lot of waterbirds choose to adjust their behavior strategies in order to adapt to the environmental changes,and shifting their foraging habitat from natural wetlands to artificial wetlands to obtain sufficient energy source and living space.Exploring the changes in behavioral pattern in different habitats can further our understanding of how waterbirds adapt to habitat shift through behavioral strategy adjustment.In October 2017-April 2018 wintering period,we used the focal animal sampling method to explore the vigilance pattern of two geese(White-fronted Goose and Bean Goose)with dominant population in both natural and artificial habitats in Shengjin Lake National Nature Reserve.We used the linear mixed model to examine the effect of habitat shift,group patterns(single-species flock and mixed-species flock),group size(number of single population)on vigilance and alert distance of wintering geese,and the differences of vigilance and alert distance in two geese.The results of research are as follows:1.The percentage of time spent vigilant and mean scan duration in rice paddy fields were higher than natural wetlands,while the vigilance frequency between two habitats was not significantly different.The alert distance of white-fronted geese in natural wetland was significantly higher than rice paddy,but there was no difference for the bean geese in different habitats.2.The time spent vigilant of single-species flocks of white-fronted geese was higher than that of mixed-species flocks,while there was no significant difference between two group patterns in the vigilance frequency and mean scan duration.The group pattern has no significant effect on vigilance of bean geese.3.There was a significant negative correlation between the group size of wintering geese and time spent vigilant,mean scan duration,vigilance frequency and alert distance,that is,the vigilance level of two geese decreased and the tolerance increased with the group size.4.There was no significant difference in alert distance,the percentage time spent on vigilance and mean scan duration between white-fronted geese and bean geese,but the vigilance frequency of white-fronted geese was higher than bean geese.5.The time spent on foraging of wintering geese in rice paddy fields was higher than that in natural wetlands,but there was no significant difference between two group patterns and species.In addition,the time spent on locomotion was higher in natural wetlands,while the percentage of time spent on maintenance of bean geese was higher than that of white-fronted geese.The results showed that increased their vigilance level when they moved their foraging habitats to rice paddy fields with intense human disturbances,and the white-fronted geese also reduced their alert distance by mixing with bean geese,so as to obtain more foraging opportunities.Based on the above results,we suggest reduction of anthropogenic disturbance in the artificial wetlands of buffer zone of core area and habitat recovery of natural wetlands to facilitate conservation and management of waterbirds in the reserve.