A falcon lands on a rust streaked ledge, hundreds of feet above a power plant roof.
Below her, turbines hum and transformers tick.
She is not nesting on a cliff.
She is nesting on a power plant.
And she is not the first.
Across Wisconsin, falcons have been raising chicks on rooftops like this one for more than thirty years, and the number behind that habit is stranger than any single nest.
Why a smokestack looks like a cliff to a falcon
Peregrine falcons evolved to nest on sheer rock faces, the kind of ledge a climbing predator cannot reach and a parent can watch from above. A tall industrial roof offers close to the same geometry, height, a flat lip, open sightlines and no easy way up. Many of these plants also sit on open water, which is where the birds hunt. Utility crews worked this out decades ago, and they began bolting nest boxes with gravel floors onto roof edges and ledges high above the turbine halls, and the falcons moved in.
Not because the plants are wild, but because they are tall and hard to climb in the one way that matters, no ground predator reaches a chick up there. The gravel mimics a scrape on stone, and the rim of the box keeps eggs from rolling into open air.
A peregrine does not seem to care whether the cliff is limestone or steel. It only cares that the ledge is high, flat and undisturbed, and a pair that raises chicks successfully tends to return to the same spot the next spring.
The season that just played out on four rooftops
This spring the pattern held at four plants, Oak Creek, Weston in Rothschild, Port Washington and the Valley Power Plant in Milwaukee, where adults known to camera watchers as Joel, Essity, Sheldon and Barney settled back into boxes they had used in previous seasons. By early April the utilities counted ten eggs across three of those boxes, three at Weston, three at Port Washington and four at Oak Creek, with the Milwaukee pair still to lay.
The adults take turns incubating, and the first chicks follow roughly a month after the eggs appear. By the middle of May the four boxes held seven chicks and six more eggs between them.
Crews maintain the boxes and otherwise stay out of the way. None of it is staged, the falcons pick the boxes, lay on their own schedule and raise whatever survives the usual hazards of a first summer aloft, several hundred feet above machinery built for something else entirely.
What decades of rooftop nesting actually add up to
The number worth keeping is not the eggs. Since the two utilities began installing boxes in the early 1990s as a recovery effort, 465 peregrine falcons have hatched at their power plants, a tally the companies report each season as about a fifth of all the peregrine falcons born in Wisconsin over that stretch.
That figure is a running count of hatchlings since the boxes went up, not a share of the birds alive in the state today. The distinction matters, because the wild population has been growing the whole time the count has been accumulating.
The birds were reintroduced after DDT exposure thinned eggshells and collapsed the population across the Midwest. Recovery workers leaned on any tall structure available, bridges, churches, office towers, grain elevators and smokestacks alike, which helps explain why the industrial afterlife of energy infrastructure keeps producing these odd biological footnotes.
Where the count gets fragile
Concentrating part of a recovery on a few industrial roofs has limits. If a box fails, an adult is lost or a plant is torn down, a slice of the program’s breeding capacity goes with it, and replacements are drawn from the same small pool of wandering unpaired birds.
The cumulative fifth also flatters the present. In the most recently reported season, statewide monitoring logged a known minimum of 103 young at 40 successful nest sites, while the power plant boxes produced about a dozen, according to the annual statewide nesting report compiled by the same biologist who manages the utility boxes.
Nest failures happen on rooftops exactly as they do on cliffs. The program’s strength is also its limitation, a recovery built on uniform, maintained structures rather than a restored landscape, and that same clustering shows up wherever wildlife settles around a single piece of energy hardware.
A naming contest on top of a power plant
Each spring now carries its own small ritual. The utilities run a public naming contest for the season’s chicks, with recent classes named after earlier birds from the program and, this year, after local news anchors and meteorologists.
It is a modest gesture, paired with cameras that run through the nesting season. Returning adults carry bands and documented histories, which is how individual falcons stay traceable from one year to the next.
What began as scaffolding for a collapsing species has turned into a durable set of rooftop breeding sites. The falcons never asked for industrial roofs, they found the tallest, quietest ledges on offer and decided the smokestacks would do.
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