Sunday, March 11, 2012

Barn Owl Chick Feathers

Around this time of year, I get a chance to see barn owl chicks up close in the World Bird Sanctuary’s propagation department. 
  Barn Owl chick at 1 week -- at this stage the feather follicles are very visible
Barn Owl chicks hatch with every feature perfectly formed--just on a very small scale.  Their closed eyes are surrounded by the beginnings of little facial discs.  Each foot is covered with impossibly small, yet perfect scales, and each toe is tipped with a sharp little talon.  Along the length of pink, nearly transparent skin covering their bodies, are rows of very active little feather follicles.
Barn Owl chick - 2 weeks old - showing the beginnings of its fluffy white down 
When I first saw a barn owl chick, I was surprised to see that its body was not entirely covered with feathers, as I thought a bird’s body must be.  Instead, it appears that the little bird is wearing a pinstripe suit with pink and white fluffy stripes.  The feather follicles form only along certain regions.  The gaps of bare skin in between the follicles are called apteria.  Birds can raise their feathers to allow air to circulate along the apteria.  This helps the birds keep cool, which is crucial considering that birds have one of the highest metabolic rates of any animal on earth.
  Barn Owl chicks at 3 weeks - covered in its insulating layer of down
When the owlet hatches, it is covered in a fine, natal down.  Soon, this stringy down is replaced with fluffy white down.  The growth of this layer of down is readily visible from day to day, and is nature’s best insulating material.  I wonder if the early down feathers that the young chicks grow resembles the integumentary feathers found on some fossil dinosaur species, such as Sinosauropteryx prima, a small theropod discovered in the Yixian Formation in China.
Barn Owl chicks at 7 weeks - still in down but already beginning to develop its wing feathers  
Could the development of feathers in an individual bird’s life somehow mirror the development of feathers on a much larger time scale?  I don’t know, but when I watch the barn owlets, I see something very primitive, intricate, and beautiful develop right before my eyes.  Every aspect of the owl, from its behavior as an adult education bird, to the development of its first feathers provides me with an endless source for questions and a deep sense of appreciation for the complexity of life on earth.

Submitted by Leah Sainz, World Bird Sanctuary Naturalist/Trainer

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