On the banks of the Mississippi near its confluence with the Missouri River, visitors have a new place to go to experience the sight of migratory birds, including Bald Eagles, Trumpeter Swans, and Great Blue Herons.
It’s called Avis Spiralis, or “spiral bird,” and it’s open to the public.
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Cast-in-place concrete, the 20-foot-tall structure is more than a bird blind. It’s the culmination of years of study and research by a local professor.
“My research has been focused on concrete, in particular the performative aspect of the material,” says Pablo Moyano Fernández, associate professor of architecture at WashU’s Sam Fox School of Design & Visual Arts. “My research is trying to push the boundaries and really challenge the typical way we use the material, and this project is a showcase of that.”
The idea for Avis Spiralis, set on the grounds of the picturesque Audubon Center at Riverlands, was inspired by another nearby bird blind. That blind, after years of exposure to the elements, had started to deteriorate and require maintenance. Moyano Fernández, who had no previous experience building bird blinds, nevertheless saw an opportunity. By designing a new blind, he says, he could test the sustainability of concrete, as well as implement a new concrete-casting system he developed called Opus Versatilium.
According to Moyano Fernández, 85 percent of the concrete he used to build the blind is made using locally sourced components; the sand is from the Missouri River and the gravel is from a quarry four miles away. “The only thing that is not local is the cement, which is applicable to most building sites around the world,” he says.
In addition, concrete requires very little maintenance, making it ideal for a project so close to water. If the area near the blind floods, a basic cleanup with a hose is all that’s needed, says Moyano Fernández. In addition to flood waters, concrete also stands up to fires, tornadoes, even some earthquakes, depending on the magnitude. “You don’t have to worry about the deterioration of the project,” he says.
Moyano Fernández’ Opus Versatilium, the new concrete-casting system, is rooted in ancient methods of construction with a key difference being the quality of the concrete, which is much stronger and “therefore you can go thinner, you can use less material,” he says.
Advances in digital technology, including 3D-printers and Computer Numeric Controls, aided the actual building of the molds, too. “If you had to do this in a traditional way, it would be extremely expensive because of the curves [on the blind],” he says. Using Moyano Fernández’ casting system, the molds can also be reused over and over again, saving money and lessening waste.
As for the design of the blind, Moyano Fernández worked with Ken Buchholz, center director of Audubon Center at Riverlands, and the Army Corps of Engineers, which maintains the site. The location of the blind, near Heron Pond, attracts migrating birds; its proximity to a public road allows for easy access. Moyano Fernández says he didn’t get a lot of direction from Buchholz, except that the initial design should be taller. “They envisioned it more like a tower,” he says. “We ended up doing a spiral.”
Creating a promenade, “a bit of a journey” up and around the spiral facilitates a 360-degree view of the river, the environment, and the birds. “At the end, there’s a bench area where you can watch birds,” he says.
Construction on the blind began on June 12, 2023. Moyano Fernández helped raise funds for the project and did most of the building labor himself. “I would say 98 percent of the project was done by me.”
“I completely underestimated the time it would take me,” he continues. “I knew it was going to be long, maybe a year, but it ended up taking twice as long.”
The blind was completed on October 4, 2025. The end result, though, was worth it.
“This project can last hundreds of years. I’m not exaggerating,” he says.
