Research reportEffect of head turns on the localization accuracy of sounds in the European starling (Sturnus vulgaris)

- We assess the effect of head turns on sound localization accuracy in a bird species.
- Turning the head increases localization accuracy under closed-loop conditions.
- Head turns under open-loop conditions are disadvantageous for localizing sound.
- We discuss binaural cues generated by head turns in respect to sound localization.

Long signal durations that represent closed-loop conditions permit responses based on the sensory feedback during the presentation of the stimulus, while short stimulus durations that represent open-loop conditions do not allow for directed head turns during signal presentation. A previous study showed that for broadband noise stimuli, the minimum audible angle (MAA) of the European starling (Sturnus vulgaris) is smaller under closed-loop compared to open-loop conditions (Feinkohl & Klump, 2013). Head turns represent a possible strategy to improve sound localization cues under closed-loop conditions. In this study, we analyze the influence of head turns on the starling MAA for broadband noise and 2 kHz tones under closed-loop and open-loop conditions. The starlings made more head turns under closed-loop conditions compared to open-loop conditions. Under closed-loop conditions, their sensitivity for discriminating sound source positions was best if they turned their head once or more per stimulus presentation. We discuss potential cues generated from head turns under closed-loop conditions.