In the 19 years, St. Louis naturalist Mark H.X. Glenshaw has studied Charles the great horned owl in Forest Park, the owl has fathered 27 owlets with seven mates.
“Charles just keeps unfolding new chapters in his life,” said Glenshaw, who visits the park daily to observe Charles and the other great horned owls that call the park home. “He's just an endlessly fascinating owl, and the dynamics of the owls and their interactions in the park are complex and ever-growing.”
Glenshaw was excited to see Charles pair with his seventh mate, Tess, in 2023. Glenshaw expected they would begin to nest, but, on Nov. 16, 2023, Glenshaw saw Tess for the last time. He said she looked fine, with no indication of illness or injury.
“Unfortunately, the only real conclusion I can draw from her disappearance is that she most likely died,” he said. “So Charles was, again, single.”
Shortly after Tess’ disappearance, a new female great horned owl entered the scene. She was “a little clumsy,” Glenshaw said, and her head bobbing behavior indicated that she’s about a year old. He named her May, as she and Charles are in a “May-December romance.”
They didn’t mate in 2024, and this year, the mating season has come and gone with no sign of mating and nesting from Charles and May. Glenshaw said it’s likely due to May being so young and inexperienced in mating behaviors.
“Charles really knows what it takes to have a successful parenting partnership, and I think Charles looked at her and said, ‘You're lovely and awesome, but you don't know what you're doing, and I'm not going to go there with you yet,’” Glenshaw said. “This year, May has matured. She's even grown physically, but it's still clear that she's still learning about the birds and the … birds.”
Glenshaw added that unusually warm temperatures last fall were likely a contributing factor to the couple’s ongoing courtship. Typically, owls will hoot together with growing intensity as they build to mating and nesting in the early winter. These duets are how they court and bond with each other — and how they declare and defend their territories.
“Unfortunately, we had the fourth-warmest autumn in St. Louis history, and I think this threw off the owls,” he said. “Instead of duetting intensely on brisk autumn nights, with autumnal temps in the 70s and higher, they hooted together less intensely — and on some nights not at all. When temperatures finally began to decline, they had less time to build up to mating and nesting through duets.”
Mark Glenshaw joined St. Louis on the Air to share his recent observations of Charles and the other great horned owls in Forest Park. Hear the entire conversation on Apple Podcasts, Spotify, YouTube, or by clicking the play button below.
Related Events
What: Forest Park Owls: Hiding In Plain Sight
When: 1 p.m. March 16
Where: Ballard Nature Center (5253 E. U.S. 40, Altamont, IL 62411)
What: Forest Park Owls: Hiding In Plain Sight
When: 6:30 p.m. April 9
Where: University City Public Library (6701 Delmar Blvd., University City, MO 63130)
What: Forest Park Owls: Mating, Nesting and Owlets
When: 6:30 p.m. April 17
Where: St. Louis Community College-Forest Park campus (5600 Oakland Ave., St. Louis, MO 63110)
“St. Louis on the Air” brings you the stories of St. Louis and the people who live, work and create in our region. The show is produced by Miya Norfleet, Emily Woodbury, Danny Wicentowski, Elaine Cha and Alex Heuer. Jada Jones is our production assistant. The audio engineer is Aaron Doerr.
