As if hummingbirds weren’t fascinating enough.
Numerous studies have focused on the mechanics of hummingbird flight, but a recent study by biologists at the University of British Columbia (UBC) zeroed in on how hummingbirds process visual signals, whether they are rocketing by at up to 60 miles (100 kilometers) an hour, or hovering in place sipping nectar.
Members of the Altshuler lab at UBC are interested in studying flight, and they were intrigued by the ability of hummingbirds to zip around quickly and then stop and hover in midair.
In 2014, scientists found that the hummingbird’s ability to hover is contingent on the bird having a completely stationary visual field, and it is “surprisingly easy to hack.” Results of that study suggested that the hummingbird brain is precisely wired to process movement in its field of vision, and that it gets overwhelmed by even small stimuli.
In birds, the area of the brain responsible for processing visual signals is known as the lentiformis mesencephalic (LM). Previous studies have shown that the hummingbird LM is enlarged in comparison to other birds, and results of the current study show that this key area of the hummingbird’s brain processes motion in a unique way.
The team at UBC thought that the hummingbird brain might be tuned to pick up on slow movements, but their experiments showed that hummingbirds are most sensitive to fast visible motion. Also, almost every neuron was tuned to a different direction, and hummingbirds responded equally to movement in any direction. In comparison, in studies of four-limbed vertebrates, most of the neurons in the motion-detecting area of the brain were shown to be specially-tuned to movements in the forward motion – motion coming from behind.
In a press release, principal investigator Andrea Gaede said, “This study provides compelling support for the hypothesis that the avian brain is specialized for flight and that hummingbirds are a powerful model for studying stabilization algorithms.”
Hummingbirds have been filmed and photographed many times, under various conditions, to study their aerial acrobatics. If you want to see what happens when you put a hummingbird in a wind tunnel, check out the following video:
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