Identification and characterization of vocalization of the Blue-Throated Barbet (Megalaima asiatica)

Abstract

Birds primarily communicate through their vocalizations, as their sense of smell is absent because their olfactory system is not as well-developed compared to their vocal capabilities. Birds with extensive and intricate vocal displays also communicate through non-verbal sounds. Determining the range of vocalizations an animal possesses sets a foundation for recognizing the significance of acoustic signals in their courtship and social dynamics. The use of computer software for analyzing bird vocalizations is a powerful and efficient means of conducting such analysis. The vocal patterns of non-passerine members have received limited attention compared to those of singing birds. Singing is absent in non-passerine birds but they rely on calls for the exchange of different information. By studying different calls of non-passerine birds we can learn deeply about bird communication and associated behaviors. Materials and Methods The study area for recordings was made by a directional microphone connected with a digital recorder and birds were recorded from Islamabad National capital of Pakistan because in this city dense forests and plains are present which is a suitable environment for many birds. The recordings were analyzed on visual inspection of the spectrogram and other acoustic characteristics. The vocalization rate is also considered. The identification of various call types was achieved through the visual inspection of spectrograms and waveforms of vocalizations and the corresponding behaviors observed in the field in the present study. Characterization of calls is done on the basis of Spectro, acoustic, and statistical parameters. Ten acoustic variables were selected for call characterization. Results Calls were characterized into four different categories. Seven out of ten variables are significant by the stepwise regression model, and then significant variables are classified 96.8 % by DFA into predicated call categories which are on the basis of spectrogram analysis. The first two functions in DFA showed maximum variance (Function1:86%, eigenvalue=13.4; Function 2:13 %, eigenvalue=2) and showed highly significant differences between the different types of calls (Wilks’ λ DF1/3 = 0.019, df = 21, P < DRSML QAU Abstract Identification and characterization of vocalization of the Blue-Throated Barbet (Megalaima asiatica) x 0.001 and Wilks’ λ DF2/3 = 0.269, df = 13, P < 0.001). Using the cross-validated method, DFA classified the vocalizations correctly into the predicted vocal categories that we initially classified on the basis of spectrographic examination. The DFA correctly classified 99% (344/348) of Kutrook-Kutrook type 1, 99% (102/104) Touk calls, 87.3% (96/110) of Kutrook-Kutrook type 2 calls, and 98% (98/100) of Kurrrrrrr calls. The Kruskal-Wallis ANOVA was utilized to determine differences among vocal categories, excluding non-significant variables. Subsequently, a post-hoc Mann Whitney U-test (2-tailed) was performed for multiple group comparisons. The Holm's sequential Bonferroni procedure with alpha = 0.05 was implemented to adjust the results of the multiple-comparison Mann-Whitney U-test. The data is shown as mean ± S.E. A difference was considered statistically significant if P < 0.05. Conclusion In the present study, the vocalization of blue-throated barbet is characterized by four different calls. Our results enhance the understanding of the vocalizations of adult Blue-throated Barbets and establish a baseline for future comparative studies with other species of Barbets. Further research should aim to uncover the complete vocal range of Blue-throated barbet and investigate the role of these calls role in courtship, social biology, and individual