Friday, October 26, 2012

Owl of the Week: Boreal Owl
At first sight, you may think, "The Great-Horned Owl got it wrong, these aren't pictures of Boreal Owls, they're pictures of Saw-Whet Owls!"  Alas, I am not wrong, we just have a case of lookalike birds on our hands (talons?).  The Saw-Whet Owl, which we'll explore next week, is a size down from the Boreal Owl, but otherwise they're very similar in appearance (I'll write a comparison of the two owls' appearances next week once we have pictures of both).  However, they're also different in many ways, so let's get going with the Boreal Owl!

These birds are not super common in these parts.  A small finger of their range extends south from Canada into the US's Rocky Mountains, but for the most part the Boreal Owl is found in far northern North America and Eurasia, in (wait for it) Boreal forests.  They hang out at high elevations when they're at these latitudes, usually in old-growth spruce-fir forests, where they nest in cavities in large trees and snags.  They're reclusive and very much nocturnal, so odds aren't high of you spotting one in the wild.  In fact, the Rocky Mountain Raptor Program sees these birds very rarely, only a handful over that past decade or so.  When they are out and about, they're hunting small rodents such as voles.

Immature Boreal Owl
Some interesting facts about Boreal Owls:

  • Almost all raptors show what is known as "reverse sexual dimorphism", meaning the females are almost always larger than the males.  The Boreal Owl has the most extreme reverse sexual dimorphism of all the North American owls: males tip the scales at a max weight of 4 oz, while females have a minimum weight of 4.5 oz, and can weigh up to 7 oz, almost twice that of the largest males. 
  • Instead of forming life-long mated pairs like most owls, the Boreal Owl only pairs up for a season, then finds a new mate next year. 
  • The chicks look dramatically different than the adults, with an all-over chocolate-brown plumage.
  • I tried finding a legitimate reason for why their Latin name is Aegolius funerus, but while the first bit is easily explained (it means 'owl'), there's no info on why the second name is "funeral."  You'd think a name like that would have some good folk lore behind it, but alas. Check out those feathered feet! 

As I mentioned earlier, the Boreal Owl is not seen often at the RMRP.  In fact, one of the last Boreal Owls admitted at the RMRP caught a ride down to Fort Collins from Cameron Pass wedged into the grill of a truck.  However, though not often seen, they face the same threats as other forest-dwelling raptors in the region:  habitat loss from logging (these owls are quite picky about living in large-diameter trees only), and injuries from window strikes and car hits.  And whenever an injured Boreal Owl is brought into the RMRP, you can rest assured it received the best care possible.

Stay tuned next week for information (and stories) about the tiny-but-mighty Northern Saw-Whet Owl!  Two of these little fighters have been admitted to the RMRP in the past couple weeks.  As always, you can email me with questions or comments at, follow me on Twitter @RaptorProgram, check us out on Facebook (Rocky Mountain Raptor Program), and find out more information and stories on our main website (which is brand new and shiny!).  If you would like to subscribe to this blog, use the box in the toolbar to the right.  Thanks for reading and supporting the RMRP!


  1. Hi there. Just reading your story about Boreal owls and Northern Saw-Whet Owls. I live in Toronto, Ontario, Canada, and this past Friday, my wife and I came upon an adult Saw-Whet Owl out in the bush. This was the first time as birders that we had ever seen a Saw-Whet Owl. Fortunately, we had our camera with us and got some good pictures and video. We have posted them for anyone interested at:

    1. Beautiful! Glad you got to see one of those birds. Check back next week for an article about Saw-Whet Owls!