Avis Spiralis

Avis Spiralis, or “spiral bird,” is a one-of-a-kind bird blind and observation tower at the Riverlands Migratory Bird Sanctuary designed and constructed by Professor Pablo Moyano Fernández of the Sam Fox School of Art & Design at WashU in collaboration with Audubon, and U.S. Army Corps of Engineers.

The structure tests the sustainability of concrete and a new concrete-casting system Fernández developed called Opus Versatilium. About 85 percent of the concrete used to build the blind and observation tower was made using locally sourced materials. The sand was from the Missouri River and the gravel is from a nearby quarry.

Dedicated in October 2025, the 20-foot-tall Avis Spiralis overlooks Heron Pond, the jewel of the wetland habitat expanse at Riverlands and a popular birding location. Heron Pond is an ideal spot to see herons, egrets, shorebirds, waterfowl and many other migratory birds. It includes a built-in bench and holes in the shape of soaring birds and has amazing 360 views of the Sanctuary!

Avis Spiralis sits directly across Heron Pond from the first blind built and installed by the WashU School of Architecture at Riverlands in 2013 also in partnership with Audubon and the Corps. The Heron Pond Avian Observatory was featured in an Audubon Magazine article about bird blinds in 2017. https://www.audubon.org/magazine/windows-another-world-take-tour-of-bird-blinds-across-country

Avis Spiralis and the Heron Pond Avian Observatory are open to the public from dawn to dusk. Maps, bird checklists binoculars checkout are available at the Audubon Center to enhance your birdwatching experience!