Friday, February 15, 2008

Country Raptor: The Uncommon Rough-legged Hawk

All photographs by Marian Anderson

Family Accipitridae- Rough-legged Hawk, Buteo lagopus

Many thanks to Marian Anderson, who has taken me to see any number of the raptor spots she's spied on her trips through rural areas and for catching this Rough-legged Hawk with her camera. Not an easy thing to do around here.

(No, they don't have particularly dry skin, but they do have feathers down to their ankles. Hey, it's nippy in the Arctic.)

Uncommon and far less often seen than their cousins the Red-tailed Hawks, Rough-legged Hawks are diurnal raptors of open country, who often hover on beating wings when hunting.

Like several other raptor species, Roughies exhibit polymorphism in distinct light and dark plumages. Siblings within the same brood can exhibit both color morphs. Above is a dark morph.

Interestingly, the buteo species that exhibit polymorphism are open country birds, and the open country Falcon, the Gyrfalcon also has morphs. Nobody as yet has figured out just why this is a plus in open country. I always thought that Wisconsin was a hot bed of Krider's Red-tails, the very light morph, because there is so much snow here so much of the time. It would seem that having more white would help in hunting. This doesn't seem to be the case with Roughies.

Though of course this isn't their breeding grounds, so perhaps it makes a difference depending on your region of the Arctic.

They are shaped like a buteo-they are one after all, but they have a longer tail and wings than a Red-tail.

Field identification marks include a dark patch at the wrist, a white tail with a black band or bands toward the tip. The dark morphs lack white to the rump but have a big patch of white that distinctly shows on the underwing flight feathers as you can see above.

In summer their range extends up into the Arctic and they're circumpolar. In an influx winter like this one, they can be seen all the way down to the Southern U.S. and Central Eurasia. Their habitat includes Tundra escarpments, Arctic coasts and in winter-marshes, open fields, and plains.

As you can see, the Roughie has "fingers", long primaries like Pale Male and Lola. I've always wondered what in particular was the advantage of those fingers and figured it might have something to do with "steering".
The Sibley Guide to Bird Life and Behavior says,"These 'fingers' provide an aerodynamic advantage in allowing the birds to fly at lower speeds without stalling."
Ah. I'd hate for them to just plummet, beak first, if they happened to be distracted and forgot to flap.
So what is the story on nests? Rough-legged Hawks can use trees but in far northern breeding grounds they nest on the ground. (Gosh, no trees up there. What else can a smart adaptive hawk do? )
Another buteo factoid from the previously metioned book, both sexes work on the nest but as as it gets closer to egg laying the male does most of the fetching and carrying.
That tidbit was for those who have commented on Lola perhaps not doing her half of the work in nest building. Well it's for the good of the species. The hen laying out a bit and conserving her strength for the long haul to come on the nest is normal. And being normal means it's evolutionarily better and therefore it increases chances of reproductive success.
I know that the nest built on 927 during Pale Male's first successful season from what I've been told, probably had more sticks placed by his mate than by himself. That makes perfect sense too. She was more experienced than he was and she was showing him how many would be needed for a successful nest---and it worked. Red-tails can learn from life experience and I wouldn't be surprised if that wasn't the case with Rough-legged hawks and the rest of the buteos as well.

Dawn. Here comes the sun in prime Rough-legged Hawk country.
Donegal Browne


Karen Anne said...

"That tidbit was for those who have commented on Lola perhaps not doing her half of the work in nest building. "

I think I'd rather build the nest than push out those eggs. Oooffff :-)

Anonymous said...

You can say that again!