These minute birds – which use their amazing hovering skills to harvest nectar – have to feed almost daily or they will perish. Given tat they inhabit regions that are not exactly arid, they are almost certain to be forced to fly in the rain at some point.
Armed with five Anna’s Hummingbirds (Calypte anna), a garden water-gun and a laboratory, Victor Ortega-Jimenez and Robert Dudley of the University of California, Berkeley aimed to work out just how much it cost them to do so.
They placed the birds in Perspex cubes and watched them feed under light, moderate and heavy simulated rain. Light and moderate rain had little effect on the birds, but heavy rain made them adopt a more horizontal posture and substantially increased the frequency of their wing beats (as shown in the slightly John Woo-esque video below), the researchers report in Proceedings of the Royal Society B.
“We demonstrated that hummingbirds can deal very well in light-to-moderate precipitation, practically without costs,” says Ortega-Jimenez. “But, even in heavy rain, despite the evident postural and wing kinematic changes produced by drop impacts and plumage wettability, these tiny birds can maintain flight control.”
See also: Mosquitoes don’t let the rain get them down – High-speed video reveals how flying pests remain airborne when raindrops strike.
Image and video: © Victor M. Ortega