Hovering hummingbirds cope with wet weather by shaking their heads at ultra-high speed to remove water droplets.
Slow-motion footage has shown that the tiny, delicate birds shakes their heads with such acceleration that it can reach a G-force of 34 (Formula 1 racing cars typically reach less than 6G). This mid-air manoeuvre takes just 0.1 seconds and removes almost all of the water droplets from its feathers.
Professor Robert Dudley of the University of California, Berkeley, one of the authors of a study published in Interface, the journal of the Royal Society, said: “It is the extreme mobility – its head is going through 180 degrees in a 10th of a second or less – it is just extraordinary."
Anna's Hummingbird is found in cloud forests and the neo-tropics, where rainy days are common, and is able to remain active even in very wet weather.
The researchers trained their cameras on a bird as it fed from its feeder, and then sprinkled it with water.
Lead author of the study, Dr Victor Ortega-Jimenez, from the University of California, Berkeley, said: “We simulated three different types of rain – and the hummingbirds did this extreme oscillation in light, medium and heavy rain. It seems it is a common behaviour of hummingbirds.”
The researchers were surprised that the hummingbirds were able to generate such extreme forces while in flight.
Professor Dudley said: “We know visual information is the key to flight control, and, obviously, when you are shaking your head, you don’t have that input of flight acceleration, and yet they remain basically stable – they are not falling out of the air.”
The scientists said their findings could help engineers to develop micro air vehicles that could cope with unsettled weather, or even washing machines with an improved drying spin.
Watch the footage here