Hummingbirds use compensatory eye movements to stabilize both rotational and translational visual motion

To maintain stable vision, behaving animals make compensatory eye movements in response to image slip, a reflex known as the optokinetic response (OKR). Although OKR has been studied in several avian species, eye movements during flight are expected to be minimal. This is because vertebrates with laterally placed eyes typically show weak OKR to nasal-to-temporal motion (NT), which simulates typical forward locomotion, compared to temporal-to-nasal motion (TN), which simulates atypical backward locomotion. This OKR asymmetry is also reflected in the pretectum, wherein neurons sensitive to global visual motion also exhibit a TN bias. Hummingbirds, however, stabilize visual motion in all directions through whole-body movements and are unique among vertebrates in that they lack a pretectal bias. We therefore predicted that OKR in hummingbirds would be symmetrical. We measured OKR in restrained hummingbirds by presenting gratings drifting across a range of speeds. OKR in hummingbirds was asy..., Animals
Six adult male Anna’s hummingbirds (Calypte anna) were caught on the University of British Columbia campus (07 Feb 2022 – 04 March 2023). Animals were individually housed in 0.61 x 0.61 x 0.91-m cages and provided with ad libitum artificial nectar (Nektar-Plus, Nekton, Pforzheim, Germany & Nectar 9, Roudybush, Woodland, California, USA). All procedures were approved by the University of British Columbia Animal Care Committee in accordance with the guidelines set out by the Canadian Council on Animal Care. Animals were released back to the wild following the experiments described herein.
Method of restraint
To allow the release of the birds after our experiments, we developed a method for non-invasive restraint of hummingbirds. Head-restraint is required to study OKR in the absence of the vestibulo-ocular reflex. We restrained hummingbirds in a flight posture by wrapping them in an elastic “ACE Brand” bandage (3M, Maplewood, USA) and placing them on a plastic bed tilted 10° a..., , This folder contains all files and code related to the paper titled \"Hummingbirds use compensatory eye movements to stabilize both rotational and translational visual motion\".

Because of the size of some files (high-speed video, in particular), intermediate files are not included, as the total size of all files associated with this project is >5 tb. An example raw video is included to test pupilTracker.py. However, all videos are uploaded as high-quality MP4 files following consultation with journal staff.

The organization of these files is as follows:

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**analysisScripts** -- contains major code for collection of pupil data (python), processing of pupil data (MATLAB), and analysis and visualization (R).

\-- pupilTracker.py -- INPUT: video, DLC file, OUTPUT: file in \"rawData\". DESCRIPTION: extracts the position of the pupil using the video and a DeepLabCut file associated with that video. The resulting file combines the DeepLabCut output with the position of the pupil, tracked...