Institute for Biology II, RWTH Aachen University, Mies-van-der-Rohe Str. 15, 52056, Aachen, Germany.
J Comp Physiol A Neuroethol Sens Neural Behav Physiol. 2010 Mar;196(3):227-40. doi: 10.1007/s00359-010-0508-6. Epub 2010 Feb 7.
We studied the influence of frequency on sound localization in free-flying barn owls by quantifying aspects of their target-approaching behavior to a distant sound source during ongoing auditory stimulation. In the baseline condition with a stimulus covering most of the owls hearing range (1-10 kHz), all owls landed within a radius of 20 cm from the loudspeaker in more than 80% of the cases and localization along the azimuth was more accurate than localization in elevation. When the stimulus contained only high frequencies (>5 kHz) no changes in striking behavior were observed. But when only frequencies from 1 to 5 kHz were presented, localization accuracy and precision decreased. In a second step we tested whether a further border exists at 2.5 kHz as suggested by optimality models. When we compared striking behavior for a stimulus having energy from 2.5 to 5 kHz with a stimulus having energy between 1 and 2.5 kHz, no consistent differences in striking behavior were observed. It was further found that pre-takeoff latency was longer for the latter stimulus than for baseline and that center frequency was a better predictor for landing precision than stimulus bandwidth. These data fit well with what is known from head-turning studies and from neurophysiology.
我们通过量化自由飞行的仓鸮在持续听觉刺激期间接近远距离声源的目标行为的各个方面，研究了频率对声音定位的影响。在刺激覆盖大多数鸟类听觉范围（1-10 kHz）的基线条件下，所有鸟类在超过 80%的情况下都降落在扬声器 20 厘米的半径内，并且在方位上的定位比在高度上的定位更准确。当刺激仅包含高频（>5 kHz）时，不会观察到打击行为的变化。但是，当仅呈现 1 到 5 kHz 的频率时，定位精度和准确性会降低。在第二步中，我们测试了是否像最优模型所建议的那样，在 2.5 kHz 存在另一个边界。当我们比较具有 2.5 到 5 kHz 能量的刺激与具有 1 到 2.5 kHz 能量的刺激的打击行为时，没有观察到打击行为的一致差异。进一步发现，与基线相比，后者刺激的起飞前潜伏期更长，并且中心频率比刺激带宽更能预测着陆精度。这些数据与转头研究和神经生理学的已知数据非常吻合。
