Research Of Vocalizations Of Coot In Breeding Season

Bird vocalization,as a significant biological characteristic of birds,is an interdisciplinary subject of bird behavioristics and acoustics research.Just as morphological specificity of birds, bird vocalization has species specificity.So the study of bird vocalization has great significance on bird taxology and bird recognition in the field.Foreign researchers began to pursue their studies on bird vocalization as early as 17 th century,however,this field wasn't attached much importance to by experts and scholars in the world until 1930s.Compared to foreign countries, China began to pursue the study in this field much later,for it just started only a few related researches in 1980s.In the last few years,thanks to the development of advanced recording equipment and spectrogram analysis technologies,the study of bird vocalization has not only infiltrated into various fields of ornithology study,but also interpenetrated into many subjects in various fields,such as anatomy,physical acoustics,neurophysiology,systematics,etc.What's more,it will have a broad prospect using bird vocalization research to monitor wildlife,drive birds away from farmlands and fishing grounds,prevent bird strike,and develop tourism industry,etc.Researchers from home and abroad have done much more studies on the vocalization of forest birds than that of waterfowls.This may be due to the difficulties when recording in the field.Fulica atra belongs to F.a.atra,Rallidae,GRUIFORMES.And F.a.atr,which has great distribution in most of China,is the only one subspecies in China.The vocalizations of Coot (Fulica atra) in breeding season were recorded with recorder(lotoo,L-200,Beijing;the frequency range for sound recording is 20-20 000 Hz) and Directional Microphone(A ZDEN SGM 1X,Japan;the frequency range for sound recording is 80-18 000 Hz) in Anbang River Wetland Nature Reserve,Heilongjiang from April to June in 2008.When the adult coots in the breeding season were chirping in 10 different behaviours,I recorded in total 137 verses of monosyllabic calls of 30 individuals.These calls belonged to 5 different vocalizations:"g(?)-","dun er-","ji er","den er-",and "a-(?)r-".The fact that the syllables' fundamental frequency and principal frequency in each verse fluctuated in certain range rather than got retained in certain values really surprised me.Since the vocalizations of "den er-","ji er","dun er-" have high frequency and short duration,I speculate that these three vocalizations may be used for communication.The parents call their nestlings with "g(?)-" and "dun er-".Nestlings' calls sound like"ji--" In addition,I propose a view that the vocalizations such as the coot's which have a fluctuant fundamental frequency may have something in common with the "tone language" such as Chinese.Besides,the nestlings' calls of Coots(Fulica atra) were recorded and played back in Anbang River Wetland Nature Reserve.From the perspective of background noises,I discussed whether the development of ecotourism and the farming activities of local farmers in this Nature Reserve would disturb the normal activities of coots in the breeding season.The results of playback-experiment indicated that the background noises made by tourists and tractors would disturb the normal activities of coots in the breeding season.