Tuesday, April 16, 2013

Owl feathers

What: I found these owl feathers strung up in a yellow birch sapling at Rock Point. The feathers had been plucked from the body of the bird (there was still some flesh attached to some of the cluster of feathers indicating it hadn't just molted the feathers). Here's my process of elimination for identifying them to species:

Detail showing "fuzz" on the feathers
  • Owls have fuzzy feathers along with a leading edge of "prongs" that make it look like a comb. These together channel air over the feather (black box of physics for me) that allow the bird to fly in utter silence. Raptors (Falconiformes) have this as well, but not nearly as well developed as in owls (Strigidae). 
  • In Chittenden County, there are records of 10 owl species, according to eBird.org. Six of these species are extremely rare (barn, snowy, hawk, great gray, long-eared, and short-eared owls). This leaves me with four probable species: eastern screech, great horned, barred, and saw-whet owls.
  • Using the book Bird Feathers and the online Feather Atlas I was able to narrow it down to further. The largest feather is a flight feathers (one of the secondaries on the wing). Flight feathers are asymetrical, have a bend when looked at both in profile and head on, and the tail edge of the feather curls up slightly.
  • The white bands on barred owl flight feathers cut straight across the feather. These were just white blotches on the trailing end of the feather.
    • Barred owls also have 2 distinct colors of brown. 
  • Screech owls also have 2 distinct colors of brown on their primaries. I've also seen these before and they tend to have an orangey/reddish hue to them. 
    • The white on each feather makes a clear triangular shape
  • Given size (about 3.5" long), color (one solid color of brown), and pattern of white dots, it seems like Northern saw-whet is the best match.
We have a pair of barred owls that we see and hear frequently around Crow's Path. My guess is that the saw-whet was eaten by the barred owl, which are apparently common predators of saw-whets. I looked around briefly for pellets but didn't find any. Pretty neat stuff!

Where: Rock Point in Burlington

Other notes: Great resources are the online Feather Atlas and the book Bird feathers by S David Scott and Casey McFarland

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