The Relationship Between The Song And Morphology And The Role Of The Song In The Territorial Competition Of The Dusky Warbler

Birdsong is an important communication and plays an important role in territorial defense and mate attraction by conveying valuable information,the function of song is very closely related to mate selection and male competition.How to maintain the authenticity of signals in animal communication is one of the main problems in modern animal behavior,which is especially critical for competitive communication.Size-frequency relationship is not consistent within intraspecific populations.In dusky warblers(Phylloscopus fuscatus),peak frequency is positively correlated with tarsus length.Whether song pitch provides information about body weight is unknown.In addition,beak palys a functional role in sound production.We study the relationship between body weight,beak morphology and sound frequency.The morphology parameters and the sound characteristics were measured.In territorial competition,the size of the body usually predicts the result of the fight.Generally,if the signal is reliable,males change their behavioral response according to the level of threat from their rival's song.Identifying aggressive signals is an important goal in animal communication research because it allows competitors to resolve territory conflicts without experiencing physical combat.Syllable rate plays an important role in the competition of male birds.For a birdsong with trill,the males should tradeoff between the trill rate and the bandwidth during the production of sound.Many studies have shown that syllable rates play an aggressive signal or quality indicator in bird species competition.In addition,multiple singing behaviors such as song type switch,frequency matching and song overlap have also been proposed as aggressive signals in songbirds.We recorded songs to simulate the presence of intruders,songs from the three males of different weights and sounds at different syllable rates and syllable length were used.We then carried out playback experiments.Our results showed that the maximum peak frequency of songs correlated negatively with body weight;there was no relationship between high frequency,low frequency,maximum frequency and bandwidth of songs and culmen or beak gape;culmen was found to correlate negatively with low frequency of trill,however,there was no correlation between the culmen and high frequency,the max frequency or the bandwidth;beak gape was not significantly related to the trill traits.The results of this study demonstrate that culmen can provide information about the low frequency of trill,and vocal tract can affect the characteristics of sound.Playback experiment results suggested that dusky warbler males responded differently toward the stimuli from three different males.When faced with a heavier intruder,the maximum high frequency,maximum peak frequency of songs were lower than those of the smaller weight intruder,and the number of sentences singing was reduced.The reduction in the maximum peak frequency is especially subject to physiological constraints,which may give the other larger weight than actual weight information,he may win the competition which will not win.It shows that such a signal may play a false signal.We find that male dusky warbler responds differently to the simulated invaders with different syllable rate.In addition,males increase the syllable rate during playback;And the more the maximum of trill rate,the stronger the approaching behavior,suggesting the stronger the aggression of a male.These results indicate that the syllable rate is the aggressive signal during the competition of male dusky warbler.The increase of syllable rate may be an effective mechanism for males to transmit aggressive motivation in competition,which is a reliable signal for competition.However,it was not found that the the number of syllable plays the role of aggressive signal in playback of different syllable length,playback affects the number of syllable in male.The number of syllable increases significantly after playback.This effect needs further exploration.