Here in the Boulder, Colorado area we've been enjoying an Arctic bird to go along with the Arctic weather we're having (got to about 0° F today for the high and supposed to get near -20° tonight with worse wind chill...) On Thursday my buddy Christian Nunes reported a juvenile Rough-legged Hawk that was along the road leading to his office in South Boulder. While an unusual species around here, what made the bird special was its unwariness- he found out about the bird when a co-worker showed him a picture of it on her iPhone! Another friend of mine got some killer shots of the bird on Friday so I thought I'd better see if it was still there on Saturday. It was, and I was treated to watching it hunt along the road for a couple of hours. Even when it dropped down to fence posts along the road it would stay put as joggers, bicyclists, and motorcycles went by. It only seemed to fly to get to another hunting perch or to pounce down on prey. This is in pretty serious contrast to my prior experiences with the species. Seems like most roughies blast off if you get within 100 meters. They often won't even tolerate a car stopping nearby. It was a pleasure to have such a cooperative subject, and I got an encore today as I went back for another hour or so this afternoon (courtesy of a snow day at work.) At one point today it flew right at me and dropped to the shoulder of the road about 10 meters away. Unfortunately it came up empty on that attempt, but I did see it successfully grab some rodents. Before the snow covered them them many vole tunnels were visible in the grass on the shoulder of the road and adjacent ditch- I'll bet the hawk is slashing its way through a strong colony of them. In a couple of shots below the bird is seen eating one such critter- I consulted my mammal pro buddy Chris Wemmer (AKA The Camera Trap Codger) and here's what he said about the afternoon snack:
It looks like it may be a prairie vole (Microtus ochrogaster) which has a gray belly ("or washed with whitish or pale cinnamon"). Esp if it was in open country. It occurs in the eastern half of the state. so seems to be within the range.
It could also be the long-tailed vole (M. longicaudus), but this species occurs in woody coniferous or brushy habitats and doesn't do the vole tunnel thing. It doesn't seem to be this however from what you say about the tunnels.
You also have the meadow vole there (M. pennsylvanicus), which is dull brown above with a gray belly. Can't rule this out.
Boulder is out of the range of the sagebrush vole (Lemmiscus curtatus).
The prairie vole seems most likely to me -- the tail is strongly bicolored in the 2nd picture, which also fits.
Thanks for the input, Chris, and for the head's up, Christian! Here are some of my favs of the bird- amazing that many times it was too close to fit in the frame as it flew by me while I stood on the shoulder of the road. The snowy shots are from today, others from last Saturday. Enjoy- Bill