Barn owls (Tyto alba) use accommodation as a distance cue
Barn owls (Tyto alba) use accommodation as a distance cue
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谷仓猫头鹰 (Tyto alba) 使用住宿作为距离提示
DOI：
10.1007/bf00193542
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发表时间：
1991
期刊：
影响因子：
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通讯作者：
F. Schaeffel
中科院分区：
文献类型：
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作者：
H. Wagner;F. Schaeffel
我们研究了仓鸮（Tyto alba）啄食时眼睛调节在距离估计中的作用。猫头鹰被训练啄食放在一个小平台上的食物（图2），同时一只眼睛被遮住以消除双眼距离线索（图1）。另一只眼睛被眼镜片（-4、-2、+2屈光度）散焦或视力正常。通过从侧面拍摄猫头鹰的视频，并逐帧离线绘制猫头鹰的头部位置，分析了猫头鹰的啄行为。此外，在一些试验中，猫头鹰的调节行为是连续记录的红外线视网膜检影术与第二台相机。这个摄像机与猫头鹰的视线对准，这样就可以在啄食之前测量屈光状态。我们做了以下观察：1.镜片导致了距离估计的误差，这是高度可预测的，从镜片的度数和符号（图3）。2.镜片也改变了猫头鹰头部的位置在固定期间（图4）。这一发现以及观察到猫头鹰在啄食过程中关闭眼睑表明，“啄食长度”是猫头鹰啄食行为中的预编程参数（图2和图3）。（5，6）. 3.光折射结果表明，猫头鹰在注视过程中的屈光努力与晶状体的屈光度高度相关。在注视过程中，负透镜使猫头鹰比正透镜调节更多的空间（图8）。4.结果表明，注视目标所需的重复努力是猫头鹰估计距离的参数之一（图9），至少在单眼观察条件下是如此。这可能是猫头鹰在啄食时没有将目标置于最佳光学焦点的原因之一。结果进行了讨论，相对于在猫头鹰和住宿行为在其他鸟类的领域的深度。
We have investigated the role of ocular accommodation in the distance estimation during pecking in the barn owl (Tyto alba). Owls were trained to peck at pieces of food presented on a small platform (Fig. 2) while one eye was occluded to eliminate binocular distance cues (Fig. 1). The other eye was defocussed by spectacle lenses ( −4, −2, +2 diopters) or had normal vision. Pecking behavior was analyzed by video taping the owl from the side and drawing the owls' head position off-line frame-by-frame. Additionally, during some trials the owls' accommodation behavior was recorded continuously by infrared photoretinoscopy with a second camera. This camera was aligned with the line of sight of the owl so that the refractive state could be measured just prior to pecking. We made the following observations:1.The lenses resulted in errors in distance estimation which were highly predictable from the power and sign of the lenses (Fig. 3).2.The lenses also changed the position of the owls' head during the period of fixation (Fig. 4). This finding together with the observation that the owls closed their eyelids during pecking suggested that ‘pecking length’ is a pre-programmed parameter in the owls' pecking behavior (Figs. 5, 6).3.The photorefractions showed that the owls' accommodative effort during fixation was highly correlated with the power of the lenses. During fixation, negative lenses caused the owl to accommodate more than positive lenses (Fig. 8).4.The results demonstrate that the accommodative effort necessary to fixate the target is one of the parameters by which the owls can estimate distance (Fig. 9), at least under monocular viewing conditions.5.The total range of accommodation in the barn owls measured in our experiments did not exceed 6 diopters. This may be one of the reasons why the owls did not get their targets into best optical focus during pecking. The results are discussed with respect to the depth of field in owls and accommodation behavior in other birds.