San Antonio River Basin Bioblitz 2026

Please see our Agenda for specific survey and activitiy times.

Are you a nature-lover? Do you enjoy learning about our natural world through science and data? Come and join the San Antonio River Authority's Environmental Science team in gathering scientific data at Trueheart Ranch Nature Park!

Over the course of 4 days, you will be able to participate in one or multiple different biological surveys including:

• Birds
• Bats
• Plants & Trees
• Butterflies
• Nocturnal Invertebrates
• Amphibians & Reptiles

Want to just come out and learn from a River Authority scientist? There are also educational, guided walks and activities available to come and learn about the ecosystems that exist within Trueheart Ranch Nature Park. If you've got littles who want to be involved, join our Jr. River Warrior activities on Saturday!

Please see our Agenda for specific survey and activitiy times.

Info: Want to explore the park on your own, at your own pace and still collect environmental data? Download the iNaturalist app, and we’ll show you exactly what you need to make a comprehensive observation that can also benefit the park!

Info: Join the River Authority for a park beautification effort near our new outdoor classroom. We’ll help clear and restore a section of the historic acequia, preserving its history and keeping the park beautiful.

Info: Step back in time and explore the history of Trueheart Ranch Nature Park. Join River Authority staff for a guided landmarks tour where you’ll visit the historic ranch home, learn about the acequia that once delivered water for irrigation, and hear the story of the Otilla Dam. Along the way, discover how the San Antonio River Authority is working to modify the dam to improve fish passage and reconnect the river, helping to support healthier ecosystems for the future.

Info: Want to explore the park on your own, at your own pace and still collect environmental data? Download the iNaturalist app, and we’ll show you exactly what you need to make a comprehensive observation that can also benefit the park!

Info: Feeling batty? Join bat experts from Bat Conservation International on a walk on the trails to detect if bats are present in the park and experience nature at night!

Info: Join a Master Naturalist and River Authority scientists to discover the smaller nocturnal animals that are attracted to light! Watch for beetles, flies, moths, and more, all with a wide range of shapes, colors, and important ecological roles. No experience needed, just interest. This is a great activity to practice your nighttime photography!

Info: Join local birding experts from the Bexar Audubon Society and River Authority scientists on a birding trail walk! All levels of birding experience are welcome. Please bring your binoculars as we’ll have a limited number available to borrow.

Info: Want to explore the park on your own, at your own pace and still collect environmental data? Download the iNaturalist app, and we’ll show you exactly what you need to make a comprehensive observation that can also benefit the park!

Info: Join River Authority scientists on a guided exploration to identify and learn about the vegetation that calls Trueheart Ranch Nature Park home. Discover the vital role plants play in supporting healthy ecosystems while learning how scientists study and monitor plant communities. You’ll get access to off-trail parts of the park and discover different methods of assessing vegetation.

Info: Join River Authority aquatic biologists at the river to see how they monitor and protect fish communities in our local waterways. Discover how different parts of the river, from fast riffles to deep pools, support different kinds of aquatic life. Learn how habitat and water flow, shape where fish live and how scientists study these communities to keep our rivers healthy. Please wear closed-toe shoes. A very limited number of waders will be available.

Info: Want to explore the park on your own, at your own pace and still collect environmental data? Download the iNaturalist app, and we’ll show you exactly what you need to make a comprehensive observation that can also benefit the park!

Info: Are you curious about what wildlife is around that you can't see? Help us sort through trail camera footage from Hendrick Arnold Park and discover what animals are evading our senses. This activity requires little walking and no experience!

Info: Love snakes, frogs, and lizards? Curious about the role these fascinating creatures play in healthy ecosystems? Join experts from the City of San Antonio Parks and Natural Areas and the River Authority to discover the slithery, slimy, and scaled residents that call Trueheart Ranch Nature Park home.

Info: Want to explore the park on your own, at your own pace and still collect environmental data? Download the iNaturalist app, and we’ll show you exactly what you need to make a comprehensive observation that can also benefit the park!

Info: Did you know that soil is teeming with life? In fact, San Antonio has several different soil types that help support a wide range of ecosystems. Join River Authority scientists for a hands-on learning experience where you’ll dig into the world beneath your feet. Learn how to collect soil samples, examine soil profiles, and identify different soil types, while discovering how soil influences the plants and ecosystems around us.

Info: Join River Authority scientists on a walk to observe and identify butterflies like hairstreaks, swallowtails, and even metalmarks! This is a no-catch event, but you're welcome to bring cameras and close-range binoculars.

Info: On this educational walk, a River Authority scientist will discuss phenology, seasonal cycles like the timing of blooms, available food sources for the animals that depend on them, weather patterns, and how climate change can have an impact. No experience necessary!

Info: Did you know the River Authority operates an accredited laboratory where scientists analyze water samples from the San Antonio River and its tributaries? Stop by for a lab demo and speak with one of our laboratory scientists to learn how we monitor water quality. No reservation required!

Info: Want to explore the park on your own, at your own pace and still collect environmental data? Download the iNaturalist app, and we’ll show you exactly what you need to make a comprehensive observation that can also benefit the park!

Info: Want to explore the park on your own, at your own pace and still collect environmental data? Download the iNaturalist app, and we’ll show you exactly what you need to make a comprehensive observation that can also benefit the park!

Info: Join local birding experts from the Bexar Audubon Society and River Authority scientists on a birding trail walk! All levels of birding experience welcome! Limited number of binoculars provided, or bring your own.

Info: Did you know that soil is teeming with life? And that we have several different types of soil in San Antonio that support different ecosystems? Dig into a unique learning experience with River Authority scientists and learn how to take soil samples, analyze a soil profiles, and identify different soil types and their impact on plants.

Info: Join River Authority scientists on a guided exploration to identify and learn about the vegetation that calls Trueheart Ranch Nature Park home. Discover the vital role plants play in supporting healthy ecosystems while learning how scientists study and monitor plant communities. You’ll get access to off-trail parts of the park and discover different methods of assessing vegetation.

Info: Did you know the River Authority operates an accredited laboratory where scientists analyze water samples from the San Antonio River and its tributaries? Stop by for a lab demo and speak with one of our laboratory scientists to learn how we monitor water quality. No reservation required!

Info: Want to explore the park on your own, at your own pace and still collect environmental data? Download the iNaturalist app, and we’ll show you exactly what you need to make a comprehensive observation that can also benefit the park!

Info: Do you have a junior naturalist in your family? We invite your family to join the San Antonio River Authority’s Education and Engagement Team for a fun, educational family activity and scavenger hunt! Most appropriate for children ages 8+.

Info: Want to explore the park on your own, at your own pace and still collect environmental data? Download the iNaturalist app, and we’ll show you exactly what you need to make a comprehensive observation that can also benefit the park!

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