Raptors of Deer Flat National Wildlife Refuge

by Bob Christensen

Deer Flat National Wildlife Refuge provides excellent habitat for a variety of raptors (predatory birds).  Two of the more abundant  raptor species on the refuge are the red-tailed hawk  and American kestrel, both which not only nest, but also are readily observed spending the winter months foraging in habitats around the perimeter of Lake Lowell and among the Snake River islands. Other common but less plentiful year-round residents include the bald eagle and northern harrier. The osprey and Swainson’s hawk are common to the area in low numbers during their annual breeding and nesting season, but both migrate from the area for the winter period. (Red-tailed Hawk – American Kestrel – Bald Eagle)

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Most of my experience with raptors at Deer Flat National Wildlife Refuge has been with the resident bald eagles and the migratory ospreys. The refuge hosts two breeding pairs of bald eagles and ospreys. Both of these species gain their subsistence by catching and eating fish from Lake Lowell during the breeding and nesting seasons. I have been monitoring the nesting activities of the bald eagles for 13 years.  And since we installed the osprey webcam in 2010, I have been actively watching the osprey nesting activities opposite the refuge visitor center. I also have the opportunity of operating the webcam via remote control.
The two bald eagle nesting territories at the refuge are on opposite ends of Lake Lowell. One is in the East Side (no public access) area and the other is in the area opposite the Narrows (about one mile west of the refuge visitor center). Over the years that I have monitored these nesting territories, the Narrows pair of eagles have not been successful in raising young the last three years, but the seven years prior to that they raised one or two eaglets to fledging age. It has been more difficult to monitor the East Side nesting success because of its remoteness and inaccessibility during high water. But my observations conclude that this nesting pair has been successful in raising one or two young eagles in at least half of the years I have been watching them. (Northern Harrier – Swainson’s Hawk – Osprey)



Another interesting fact is that up to 30 bald eagles spend the winter on the Deer Flat National Wildlife Refuge. Both adult and immature birds can be seen perched in the leafless trees around the refuge and/or sitting on the ice waiting for a chance to take a duck or goose for dinner.
The two osprey nests on the refuge are on poles constructed for that purpose by refuge personnel some years ago. They are a little over one mile apart–one being just south of the visitor center within the high-water area of Lake Lowell, and the other being on the shoreline near the refuge maintenance yard SE of the Upper Dam. While I do not have exact records, I can state that over the last decade the visitor center nest has been used longer than the other. In recent years both nests have been active each year with the maintenance yard ospreys raising about two chicks a year.  However, during the last three years, the visitor center nest has been unsuccessful in raising any young; although the adult birds have been present each year.