Sound and movement are entangled in animal communication. This is obviously true in the
case of sound-constituting vibratory movements of biological structures which generate …

Highlights•Comparison of vocal individuality between life-history stages allows for
identification of selection pressures and potential strategic use by senders.•Vocal …

The origin of novel traits, those that are not direct modifications of a pre-existing ancestral
structure, remains a fundamental problem in evolutionary biology. For example, little is …

Background In the issue of biodiversity, the domestication of birds as pets and trade animals
requires special attention as a conservation effort. Lovebirds (Agapornis fischeri) are …

Variation in formant frequencies has been shown to affect social interactions and sexual
competition in a range of avian species. Yet, the anatomical bases of this variation are …

Courtship singing in songbirds is often accompanied by gestural displays, similar to human
vocalization or music that solicits body movements. This suggests that sound communication …

Background The presence of a tracheal septum dividing the trachea into two makes
intubation one of the main challenges of penguin anaesthesia. Differences in the length and …

The syrinx is the main source for phonation in birds, its function is analogous to the
mammalian larynx. Birds have both a larynx and a syrinx, but they use only the latter to …

ABSTRACT Capsule Male Western Capercaillies Tetrao urogallus use their vocalizations
during the breeding season for territorial and reproductive purposes, and these have …

Reproductive success can improve with experience, which increases with age in many long-
lived species. Signals that provide reliable information about age are therefore of …