Videos kindly provided by Dr William DeBello from the Center for Neuroscience and Department of Neurobiology, Physiology, and Behavior, University of California, Davis (https://biology.ucdavis.edu/people/william-debello)
Pena, J. L., & DeBello, W. M. (2010). Auditory processing, plasticity, and learning in the barn owl. Institute for Laboratory Animal Research Journal 51, 338-352
Knudsen, E. I., & Knudsen, P. F. (1989). Vision calibrates sound localization in developing barn owls. Journal of Neuroscience 9, 3306-3313.
1) Barn owls are able to accurately localize a target, such as a mouse on the ground, using either visual or auditory cues. This is illustrated in the following movie. The first owl to appear flies straight to its target and catches the mouse. The second owl has recently been fitted with prism glasses: its behavior looks fairly normal, but it mislocalizes the mouse and misses out.
2) This movie shows the same prism-mounted owl unsuccessfully trying to catch a mouse (it consistently aims to the right of its intended target). After several attempts, however, this animal does succeed in catching the mouse, indicating that visuo-motor adaptation is taking place to compensate for the presence of the prisms.
3) Eventually, the prism-mounted owl's auditory spatial mapping also adapts, allowing it to catch a mouse in complete darkness. Watch out for the owl perched at the back, and the mouse running along the far right edge of the arena. (This third video was taken with infrared light which is invisible to the owl).