Earthsky Interviews
Private: Night Flight
12-18-2004 - Biodiversity
_JB:_ He writes, “Pilots require an instrument called an artificial horizon to fly in darkness. Can birds fly in total darkness?”
_DB:_ Although most birds go to roost when the sun sets, there are many that can fly through a darkened sky. For example, owls hunt at night. Their eyes contain extra large retinas, which means their eyes can collect more light – so owls can see in very low light levels. In addition, some owls, such as Barn Owls, have very good hearing.
_JB:_ Birds generally have an ear system similar to that of humans. Fluid in the inner ear sloshes back and forth over tiny hairs that send signals to the bird’s brain. That’s how a bird determines whether it’s level, diving, banking or rolling. What’s more, scientists believe that some birds, particularly migratory birds, use Earth’s magnetism for orientation. Small traces of the iron mineral magnetite have been found in the brains of such birds – this mineral is thought to interact with Earth’s magnetic field.
_DB:_ And it’s possible that stars may assist some birds in flying at night. It’s thought some birds might follow particular patterns of stars to help them reach their final destinations. That’s our show – thanks today to the “National Fish and Wildlife Foundation”:http://www.nfwf.org/. We’re Block and Byrd for Earth and Sky.
Author’s Notes:
Meanwhile, some birds, such as Kestrels, can see in both normal and ultraviolet light. They use this vision to see rodent urine trails that glow in the ultraviolet range helping them to find a meal.
The following people were interviewed for today’s program. Our thanks to:
Dr Penny Olsen
Australian National University
Tony Ross