The Impacts Of Environmental And Intrinsic Factors On The Song Traits Of Parus Varius

Bird song is one of the best effective way for communication among individuals of birds,with great implications for their life.It is also considered as a behavior for the male to protect their spouse,or seek extra-pair paternity(EPP).Bird song is influenced by many factors,such as: population abundance,individual intrinsic factors and environmental factors.Individual intrinsic factors include: the birds breeding stages,body size,and so on.Environmental factors mainly include: sunrise time,month cycle,precipitation,temperature,and many others.This study examined the influence of different environmental factors on the birds song and songbirds adaptability to the environment changes,with the aim to provide basic materials for bird behavior and reproductive ecology research.Bird song is sensitive to changes of environmental factors,including both natural and anthropogenic factors.To examine the relationship between the singing behavior of varied tits and dominant environmental factors,I recorded the dawn songs of varied tits(Parus varius)between March and July in both 2014 and 2015 at Xianrendong Nature Reserve,Liaoning province.Varied tits were observed since the start of their courtship.The breeding period of varied tits was divided into three stages,including pre-laying,laying,and post-laying states.At the same time,the dawn song of male individuals of varied tits was recorded without any disturbance on their normal activities.The recording distance ranged from five to ten meters.Date,weather conditions,and the start time of dawn song were all recorded.In order to understand the responses of dawn song to different environmental factors,we recorded the dawn song of ten male varied tits both in the noisy environment with the presence of cars and tourists and in the relatively quiet forest.The first site was close to the sides of the road.The second site was located in the core area of the reserve without any disturbance.The results showed that:(1)varied tits began singing earlier as the sunrise time started earlier,indicating their high sensitivity to the light conditions;(2)the start time of dawn song was later and the sing strength was lower in the cloudy days than that in sunny days,probably because light transmission efficiency was reduced in the cloudy days and also because varied tits will allocate more energy to heat preservation in cloudy conditions;(3)the sing strength varied across different month cycle phases,with the highest sing strength presenting at the stage of full moon due to the increases of feeding time and accumulation of fat;(4)the acoustic parameters of typical songs of varied tits varied significantly,including frequency and amplitude,under noisy environment.Not only the maximum frequency of varied tits in the pre-laying stage but also the maximum frequency and minimum frequency of varied tits in laying stage were higher in noisy environment than that in forest.In this study,I analyzed the songs in different breeding periods.This method would be better to understand the function of birdsongs in breeding periods.Results from this study improve our understanding of the relationship between dawn song and environmental characteristics.Bird song is sensitive to individual intrinsic factors(such as body size and breeding cycle).I analyzed the relationship between the body sizes and sex ratio of P.varius varius and their song characters.The results showed that:(1)there was a positive relationship between integrated morphological measurement and maximum frequency of bird song;(2)there was a positive relationship between sex ratio and duration of verse of bird song;(3)the frequency in the different reproductive cycle of bird song was also different.The frequency at laying-period was the largest.The probable reason would be that male birds may want to obtain more reproductive opportunities and prevent the spouse with outside of marriage;(4)there was no significant differences in male singing frequency between nests with EPP phenomenon and that without EPP.Such a results indicate that EPP would have minor impacts on bird singing behavior.Results from this study would help improve our understanding about the relationship between intrinsic factors and bird song.