Last Updated on April 9, 2026
What happens when scientists, local partners, and a nature-loving community come together for four days? Many exciting discoveries! During the third annual San Antonio River Basin Bioblitz at Trueheart Ranch Nature Park, San Antonio River Authority (River Authority) staff, along with expert colleagues and partners, joined forces to investigate the park and document the remarkable array of life it harbors.
The 351-acre Trueheart Ranch Nature Park features several unique historical sites, including an acequia and a remaining pecan orchard. Information about the landmarks’ stories, their link to the land, past residents, and historical maintenance was shared on the Park Landmarks Tour.
Since the acequia is no longer active, dirt and debris, like fallen branches, have filled much of it. It needed a little TLC, so we reached out to the community for help—and wow, did they show up! The initial morning of the Basin Bioblitz saw enthusiastic volunteers, including many River Warriors, clearing out trash and debris to bring back the former look of the acequia. Thank you to our incredible volunteers!
Some incredible partners who shared their time and expertise supported our event. Bat Conservation International kicked things off with a Bat Walk, beginning with an engaging “All About Bats” session. Participants learned fascinating facts about the bats that live in and migrate through the San Antonio River Basin before heading out to see and hear them firsthand.
The Alamo Area Master Naturalists and the Nocturnal Invertebrates Tracking and Education (NITE) group, under volunteer Peter Hernandez’s direction, illuminated the night with light stations to draw in insects and arthropods. Participants discovered moths of all shapes, sizes, and colors, along with beetles, wasps, mantidflies, and more! DarkSky Texas provided educational materials, which helped participants learn about light pollution.
The City of San Antonio’s experts at Medina River Natural Area were valuable partners, assisting us in our search for reptiles and amphibians during the Herpetology Survey. With their help, participants encountered Western Rat Snakes, Rose-bellied Lizards, Blanchard’s Cricket Frogs, and more!
Bexar Audubon Society showed up in force on two mornings to document the many birds finding refuge at Trueheart Ranch! Birders identified 37 different species in the park, including the Verdin, Eastern Bluebird, and Osprey!
Most of Trueheart Ranch Nature Park lies within the 100-year floodplain, with the San Antonio River tracing along its eastern edge. During our Exploring Soils activity, participants learned from River Authority Environmental Sciences staff and partners at the Texas Water Resources Institute about the different soil types and how they influence floodplains and surrounding ecosystems.
The learning didn’t stop there. During “Walk with a Scientist,” participants gained insight into how the River Authority monitors fish populations and aquatic habitat health, how hydrology and physics shape the river, and how ecological processes connect across the San Antonio River Basin. They also explored phenology—the timing of natural events like blooms, migrations, and rainfall, and how these cycles are interconnected.
Throughout the Bioblitz, passionate community members documented an incredible diversity of life. Participants received training on how to use the community science app, iNaturalist, empowering them to record and contribute their own observations. Over the course of the four-day event, participants documented over 150 species, including wildlife such as Barred Owls, Coyotes, Painted Schinia Moths, Texas Logperch, Tadpole Madtom, Wild Turkey, Golden-fronted Woodpeckers, Katydids, Mayflies, and Big Brown Bats. A wide variety of plants were also recorded, including Orange Flameflower, Texas Dandelion, Prairie Verbena, Wafer Ash, Hog Plum, Smallflower Groundcherry, Nettles, and Prickly Pear Cactus.
At first glance, Trueheart Ranch Nature Park may seem like a simple network of trails, but when you take a closer look, you realize there is so much more to discover and appreciate both at this location and all around us! We hope you come experience the park yourself if you haven’t already, and join us next March for the next Basin Bioblitz!
