Department of Natural Science, Manchester Metropolitan University, Manchester, UK.
The Shamir Research Institute and the Department of Geography and Environmental Studies, University of Haifa, Haifa, Israel.
J Anat. 2022 Aug;241(2):527-534. doi: 10.1111/joa.13655. Epub 2022 Mar 21.
Many nocturnal avian species, such as Strigiformes, Caprimulgiformes and Apterygiformes, have sensitive vibrotactile bristles on their upper bill, especially on their rictus. The anatomy of these bristles can vary, especially in terms of sensitivity (Herbst corpuscle number), bristle length and bristle number. This variation is thought to be associated with foraging - such that diurnal, open foragers have smaller and less-sensitive bristles. Here, we describe bristle morphology and follicle anatomy in the western barn owl (Tyto alba) for the first time, using both live and roadkill wild owls. We show that T. alba have both narial and rictal bristles that are likely to be vibrotactile, since they have Herbst corpuscles around their follicles. We observed more numerous (8) and longer bristles (16 mm) on the nares of T. alba, than on the rictal region (4 and ~13 mm respectively). However, the narial bristle follicles contained fewer Herbst corpuscles in their surroundings (5) than the rictal bristles (~7); indicating that bristle length is not indicative of sensitivity. As well as bristle length and number varying between different facial regions, they also varied between individuals, although the cause of this variation remains unclear. Despite this variation, the gross anatomy of facial bristle follicles appears to be conserved between nocturnal Strigiformes, Caprimulgiformes and Apterygiformes. Understanding more about how T. alba use their bristles would, therefore, give us greater insights into the function of avian bristles in general.
许多夜间活动的鸟类物种，如鸮形目、夜鹰目和无翼目，它们的上喙，尤其是喙弓上，都有敏感的触须状刚毛。这些刚毛的解剖结构可能会有所不同，特别是在敏感性（赫布斯特小体数量）、刚毛长度和刚毛数量方面。这种变化被认为与觅食有关——例如，昼行性、开放式觅食者的刚毛更小且不那么敏感。在这里，我们首次描述了西方仓鸮（Tyto alba）的刚毛形态和毛囊解剖结构，使用了活体和路边死亡的野生猫头鹰。我们表明，T. alba 既有鼻前刚毛，也有喙弓刚毛，它们可能具有触须状刚毛，因为它们的毛囊周围有赫布斯特小体。我们观察到 T. alba 的鼻腔刚毛比喙弓刚毛数量更多（约 8 根）且更长（约 16 毫米），而喙弓刚毛的数量（约 4 根）和长度（约 13 毫米）都较少。然而，鼻前刚毛的毛囊周围赫布斯特小体数量（约 5 个）比喙弓刚毛的（约 7 个）少；这表明刚毛长度并不能说明敏感性。除了不同面部区域的刚毛长度和数量存在差异外，个体之间也存在差异，尽管这种差异的原因尚不清楚。尽管存在这种差异，但夜间鸮形目、夜鹰目和无翼目之间面部刚毛毛囊的大体解剖结构似乎是保守的。因此，更多地了解 T. alba 如何使用它们的刚毛，将使我们更深入地了解鸟类刚毛的一般功能。
