Nocturnal birds prefer different times of night

02-18-2019

By Zach Fitzner

Earth.com staff writer

The most obvious and iconic of nocturnal birds is the owl.  Perhaps the most widely recognized owl is the Great Horned Owl (Bubo virginianus), with its regal feathered ‘horns’ and its distinctive hooting call. Ironically, the Great Horned Owl is also one of the less nocturnal owls.  

I’ve seen Great Horned Owls just after sunset near the boundary of Colorado National Monument as well as nested in trees in the morning in South Dakota and Arizona.  I found it a little odd how many times I’d seen Great Horned Owls while never seeing a barn owl, for instance. When I learned that Great Horned Owls are incapable of seeing in absolute darkness and prefer crepuscular hours, it made sense.

Crepuscular animals are those, like mosquitoes, that are most active in the early morning and early evening hours.  Barn owls (Tyto alba), on the other hand, have more finely tuned senses and can hunt in absolute darkness, capturing mice in laboratories only by sound.  Barn owls are eerily pale, with round white faces punctuated by dark alien eyes. It seems that the unique dish shaped face prominent on the barn owl is perfect for funneling sound and amplifying the bird’s hearing.  It isn’t always just sound that allows birds to find their way in the dark, though.

The Northern Brown Kiwi (Apteryx mantelli) is a very different bird than any owl.  The Kiwi is covered in shaggy brown fur-like feathers useless for flying but great for keeping the bird insulated.  The bird looks like little besides a brown fluff ball with a long beak protruding. The World Association of Zoos and Aquariums reports that the brown kiwi has very poor eyesight, able to see less than a meter in daylight and only two meters at night.  Instead, the Northern Brown Kiwi lives nocturnally by smelling with nostrils uniquely placed at the tip of their long beaks. Living with limited senses and no ability of flight probably works so well for the kiwi only because historically there were few predators to harm it in New Zealand where it’s native.  Other birds adapt their behavior to their environment as well.

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