Yellowstone Forever

October 20, 2011

Fall Raptor Migration Monitoring

Field Location: Hayden Valley, Yellowstone National Park  (TRANSLATION)

Bald eagle in nest in YellowstoneDavid Haines: I can see a raptor which appears to be a Cooper’s Hawk.  I have used the silhouette, behavior and plumage to discern the species and age; it is north east of the observation point, traveling to the south east.  

Jeep Pagel: Can you determine if it is an adult, or if it is in subadult plumage?

David Haines: It is an adult.

Lesley Henry:  Is your Cooper’s Hawk moving past one of the more visible sighting points in the sky?

David Haines:  No.  You are seeing another raptor.  The Cooper’s Hawk is moving at tree-line level in a steady and fast flight through the valley.

Jeep Pagel: Did you see the Swainson’s Hawk flying at a high rate of speed behind it on the same track through the Valley?  

Leslie Henry: No. Is it still in your field of view?  

David Haines:  The Cooper’s Hawk is out of my view; please document it on our data sheet.   I need to look at that other buteo, which I believe may be a Ferruginous Hawk.   Also, there was a male American kestrel that was soaring near the Swainson’s Hawk.  Leslie -- can you pick it up in your field of view?   

Leslie Henry:  Yes, I see the male American Kestrel; the Swainson’s Hawk you saw is a dark morph, and I have seen another Swainson’s Hawk; a light morph, near Mt. Washburn, and it was moving to the west to the roadcut.

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