Basis of the vocal communication in hummingbirds

Monte Bauer, Amanda (2023): Basis of the vocal communication in hummingbirds. Dissertation, LMU München: Fakultät für Biologie

Abstract

Although hummingbirds draw attention to their unique hovering flight, as other birds, they strongly rely on sounds to communicate. As songbirds and parrots, hummingbirds convergently evolved the capacity of learning how to produce certain vocalizations early in life in a process similar to speech acquisition, vocal production learning, based on analogous neural substrate. During the past two decades of investigation on vocal production learning in birds, many similarities have been shown among avian vocal learners. However, comparative studies were mainly focused on the North American radiation of hummingbirds which is more than 15 million years apart to the common ancestors originated in the lowlands of South America. Furthermore, investigations on the principles governing vocal production learning in South American hummingbirds meets the lack of information about the basis of their vocal communication. Therefore, in this thesis, I investigate the vocal communication of hummingbirds using a comprehensive approach on an evolutionary perspective by focusing each chapter on a different yet complementary aspect: (i) evolution of their vocal behavior, (ii) anatomy of their vocal organ, sensibility of their (iii) vocal behavior and (iv) brain to androgens and (v) neural activity during vocalizations in the wild. I found that when investigated comparatively, hummingbirds show a number of dissimilarities concerning their vocal organ, brain and androgen sensibility when compared to other vocal learners and a hitherto overlooked heterogeneity in their vocal communication within the family. Towards the base of the hummingbird phylogeny, both sexes vocalize in similar rates independently of androgen. I propose the black jacobin (Florisuga fusca) as a model species here and in future studies to better represent the putative ancestral condition of the family. The inclusion of key yet understudied species, such as the black jacobin, in comparative studies can shed a different light on the understanding of vocal production learning in birds. This thesis paves the way to further investigations on the evolution of vocal production learning from a more comprehensive perspective.

• Dokumententyp: Dissertationen (Dissertation, LMU München)
• Keywords: Trochilidae, bioacoustics, neuroethology, vocal learning
• Themengebiete: 500 Naturwissenschaften und Mathematik ; 500 Naturwissenschaften und Mathematik > 570 Biowissenschaften, Biologie
• Fakultäten: Fakultät für Biologie
• Sprache der Hochschulschrift: Englisch
• Datum der mündlichen Prüfung: 21. Dezember 2023
• 1. Bericht­erstatter:in: Gahr, Manfred