Montana Winter Raptor Workshop Jan 09—13, 2015

Posted by Denver Holt


Denver Holt

Denver Holt is a wildlife researcher and graduate of the University of Montana. He is founder and president of the Owl Research Institute, a nonprofit organization located ...

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Our first winter raptor workshop was very successful and lots of fun. Western Montana was unusually cold and snow-covered during our trip, but our enthusiastic group was prepared. We covered many field techniques for basic and advanced raptor identification. We also discussed migration, wintering ecology, and the basics of ornithology and raptor biology. Survival in winter can be difficult, and we discussed feeding ecology and strategies used by raptors during this season. For example, Bald Eagles frequently feed on road-killed deer and, once cows start calving, after-birth. Sharp-shinned and Cooper’s hawks and Merlins hunt small birds in towns and at bird feeders, while Red-tailed and Rough-legged hawks feed primarily on small mammals such as voles. Discussions also centered on avian conservation and the strengths and weaknesses of raptor research.
We saw 10 species of birds of prey including Bald Eagle, Northern Harrier, Sharp-shinned Hawk, Red-tailed Hawk, Rough-legged Hawk, Golden Eagle, American Kestrel, Merlin, Prairie Falcon, and Great Horned Owl. We had many outstanding looks at numerous Bald Eagles and were able to observe and discuss age-related plumage differences. In fact, we observed all plumages from juvenile to adult, which covers around five years and five plumages. Our only Northern Harrier was first spotted perched atop a fence pole. This confused the group, as most harriers are seen on the wing. Eventually it took flight, and we confirmed our preliminary identification with other field marks, behavior, and habitat. Our only Sharp-shinned Hawk was very cooperative as it perched on top of a spruce tree 50 yards away while we ate lunch. With good viewing in our scope, we were able to discern all the main features separating this species from Cooper’s Hawk.

American Kestrels were somewhat easy to find. Here we were able to see the differences between males and females. Males are more abundant during winter in western Montana and normally outnumber females by a ratio of 3–1. Two Merlins provided an opportunity to discuss adult and juvenile plumage, as well as sub-species recognition. The Taiga and Prairie Merlin were both seen. Neither observation was outstanding, but one Merlin allowed our group time to work over field marks. Two Prairie Falcons provided outstanding observations. We were able to distinguish them as adults and even to suggest sex.
We easily saw over 100 Red-tailed and Rough legged hawks each. Because these species are polymorphic (e.g. have several color morphs/varieties), identification of the dark morphs was challenging. For the Red-tails, we were able to confirm Brown, Rufous, Harlan’s, Western, and a mix of unknowns. Lucky for us, we also spotted the rather rare white variety of Harlan’s. We had outstanding looks at two of these unusually plumaged birds. Although Rough-legged Hawks have incredible individual variation in plumage, we were able to get a good feel for the basic looking plumage, followed up by distinguishing between adult female and male plumage. Only one dark morph Rough-legged was seen.

We had great looks at three Golden Eagles in adult and juvenile plumages. We watched one juvenile hunt Ring-necked Pheasant, but it was not successful. We spent some time distinguishing flight characteristics and differences between Bald and Golden eagles.

Our 2015 Montana Winter Raptor Workshop was a great inaugural tour, and I look forward to next year’s trip.