South Dakota wind review found owl and hawk occupying nests originally built by bald and golden eagles

Among the wide-open grasslands of Haakon County in South Dakota, the federal surveyors proceeded with their binoculars and notebooks, observing the wildlife as part of the normal process of an environmental assessment for a wind energy facility to be built north of Philip. It all seemed pretty routine.

But then they went and looked at the nests.

These particular nests were supposed to house the bald eagles and golden eagles, but they did not contain those birds. Something else was using them now.

The Bald and Golden Eagle Protection Act, as well as the Migratory Bird Treaty Act, impose certain obligations that should be respected by developers and agencies.

A routine survey with a non-routine finding

The Interconnection Request of the Philip Wind Energy Center does not tend to make big news stories. The Final Environmental Assessment issued in May 2025 under the number DOE/EA-2094 was created by the Western Area Power Administration (WAPA) as a way to assess the environmental impact of interconnecting a proposed wind facility. Philip Wind Partners, LLC, intends to construct this wind facility on privately owned lands near Philip, in Haakon County. Before installing any turbines, federal authorities should consider what is present in the environment.

This means conducting raptor surveys. Both bald eagles and golden eagles are listed as a federally endangered species, therefore, any construction within their territory requires the proper assessment of nesting sites and activities. The surveyors expected to see typical raptor sites – large stick nests, either active or abandoned, associated with specific eagle species of the region.

Instead, they got a question – if the eagles do not nest there, then who does?

The great horned owl moves into an eagle’s home

The first surprising sight was that of a great horned owl perched on a nest known to be used by bald eagles. For anyone familiar with owl habits, such an act is bold and daring but is definitely no big surprise since great horned owls are notorious for taking over nests constructed by others.

The reason why a bald eagle’s nest is a big discovery is size. Nesting sites of bald eagles are some of the largest found among birds in North America and are built over many years and can weigh several hundred pounds. For an owl, there would be much too much room in such nests.

The more difficult question is how this will affect the eagles. Bald eagles tend to use the same nest locations in following years, and they have been seen reclaiming such nesting spots after being driven off during a season. Whether the original occupants will fight back or find another place to go to, it is hard to say without further research.

A red-tailed hawk claims golden eagle territory

In this respect, the second exchange was perhaps even more remarkable. There has been an observation of a red-tailed hawk taking over a nesting territory formerly occupied by golden eagles. The red-tailed hawk and the golden eagle inhabit the same region of the Great Plains, and ecological competition has been documented for both birds. It is already remarkable that a smaller bird occupies the nesting territory of its larger cousin.

This might indicate whether the golden eagles inhabit the area at the moment or not. In case there was an active pair in the territory, the red-tailed hawk would probably not occupy it. Its occupation indicates that the eagles might have left the territory for a while, creating the opportunity for the smaller bird.

Both exchanges happened in the same survey area and in the same federal review of it. They are usually not registered formally and publicly like this one, detailed in the U.S. Department of Energy Final Environmental Assessment.

What wind energy reviews reveal about wildlife

For one thing, federal environmental assessments of wind energy developments demand raptor surveys precisely because eagles enjoy legal protection. The Bald and Golden Eagle Protection Act, as well as the Migratory Bird Treaty Act, impose certain obligations that should be respected by developers and agencies. These are obligations that are followed by field researches that usually cannot be substituted by observations.

Cooperation of WAPA, Philip Wind Partners, and the regulatory framework around private energy development in Haakon County resulted in a document that includes in its wildlife section a footnote of ecological interest, according to U.S. Department of Energy. This footnote goes unnoticed by the majority of the document’s readers.

Raptors, real estate, and the logic of the swap

Nest piracy isn’t random. It’s a rational strategy in landscapes where large, structurally sound nest sites are scarce — building a stick nest capable of supporting a raptor family takes time and materials, so inheriting one is simply more efficient if you can hold it.

Wind energy development, and the surveys it requires, is quietly accumulating a growing body of field data on raptor behavior across the American West. Individual assessments like DOE/EA-2094 are snapshots. Taken together, though, they sketch a picture of how raptors compete, adapt, and redistribute themselves across changing landscapes. The double swap in Haakon County may tell conservationists something useful about local eagle dynamics, whether populations are stable, shifting, or thinning in ways that open territory to smaller competitors.

And there is also another thing that needs some reflection in more human terms. A field biologist flips open his data sheet, makes his way through the woods to a particular nest where an eagle is said to dwell, takes a pair of binoculars, and sees an owl. The classification has changed. The landscape operates on its own logic.