San Antonio passes Austin in the 2023 City Nature Challenge

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A group of master naturalist observers gather around a large oak tree.

Last Updated on January 30, 2024

What is the City Nature Challenge?

The iNaturalist City Nature Challenge (CNC) is a four-day annual global Bio-blitz organized by the Natural History Museum of Los Angeles County and the California Academy of Sciences. It is one of the largest community science events in the world and is held annually at the end of April. During the Bio-blitz, citizen scientists worldwide participate in this challenge to observe and document the wildlife in their cities. The main goals of the CNC are 1) helping species of greatest conservation need (SGCN), 2) monitoring changes in the range of native species, and 3) possibly identifying new species. This family-friendly challenge encourages all ages to go outside , observe nature, and contribute to valuable citizen science data while learning to identify some of the native species that inhabit our local riparian habitats as well!

This year’s challenge was held from April 28 to May 1, 2023. The San Antonio Metro Area boundary for this challenge includes 12 counties, including Bexar, Wilson, Karnes, and Goliad counties. These counties comprise the four-county jurisdiction of the San Antonio River Authority (River Authority). This challenge is vital to our San Antonio River Watershed for several reasons. First, the CNC is essential in educating the community about the vast biodiversity of species that rely on the creeks and rivers of our watershed. Second, it sheds light on the current health of our watershed, including the status of SGCN that live within it. Third, it helps with the Texas Parks and Wildlife Department’s research and conservation efforts by contributing valuable data to the Texas Nature Trackers.

Preparing for the City Nature Challenge

In preparation for the 2023 iNaturalist City Nature Challenge, the River Authority and the San Antonio River Foundation held immersive nature walks in the winter and spring of 2023 to help the community discover unique flora and fauna of the riparian areas in the southern basin of San Antonio River. Community members were also trained to record their observations using the iNaturalist app.

Master Naturalists gather under pavilion for observation event.

Volunteer and Engagement Coordinator Minna Paul leads event.

Walk on the Wild Side at Branch River Park in Goliad County.

Volunteers gather around horned toad statue at Escondido Creek Parkway.

Observers gather to admire plants.

Walk on the Wild Side at Escondido Creek Parkway in Karnes County.

Bird watching groups observes avians at Helton Nature Park

Walk on the Wild Side at Helton Nature Park in Wilson County.

How many observations were made in the san antonio river watershed?

A map depicting the amount of observations recorded across the San Antonio River Basin.

A map of observations made in the San Antonio Metro Area during the 2023 CNC. See the whole map.

This year 19,967 observations of 2564 different species by 858 citizen scientists were made in the 12 counties of the San Antonio Metro Area, which includes the River Authority’s four-county jurisdiction. This was an increase of over 3000 observations from last year’s challenge! The San Antonio Metro Area also ranked 3rd Place in the Texas City Nature Challenge, passing the Greater Austin Area for the first time in CNC history!

Winners of the Local Intra-Nature Challenges

  • Campus Nature Challenge: St. Mary’s University with 1373 observations of 581 species
  • Corporate Nature Challenge: Toyota- San Antonio with 807 observations of 259 species
  • Texas Master Naturalist (TMN) Chapter Challenge: TMN-Alamo Area with 4843 observations of 1175 species
  • Community Nature Challenge: River Authority’s River Warriors with 2590 observations of 900 species

Check out some of the wildlife observed during the 2023 CNC!

Grid image of multiple nature observations. top row left: purple martin, top right Oblique Longhorn. Bottom row left: White-eyed Vireo, bottom right: Red admiral

Photo Credit: (c) Ken Butler (CC-BY-NC) | Photo Credit: (c) Marley Diehl (CC-BY-NC) | Photo Credit: (c)dnvarga (CC-BY-NC) | Photo Credit: (c) Laura Keene (CC-BY-NC)

Over 64% of the observations made in the 2023 CNC are now research-grade. Expert naturalists and scientists will continue identifying the documented species in this challenge to contribute further research-grade data. Visit the CNC 2023: San Antonio Metro Area page to learn more about this year’s observations!

A group of people gather for a selfie after a successful nature observation event.

Two men take a photograph of a plant.

Observers take photos of nature using cameras and their phones.

CNC participants attended Bioblitz events at Cibolo Creek Ranch, Friederich Wilderness Park, and many other locations to add their observations to the challenge.

Decorative banner saying

 

Many thanks to those who attended the River Authority nature walks and contributed to the success of this year’s City Nature Challenge. Our collective support helps raise awareness and contribute to stewardship and sustainability for our local creeks and the San Antonio River!

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Related Articles

Alerts

Mission Reach Area Maintenance

Mission Reach Area Maintenance

*MARCH 2026 UPDATE*

Ongoing stem-density maintenance is currently taking place in this area. Crews will be working Monday through Friday during daytime hours. We appreciate your patience as we complete this important work to maintain and enhance the park for everyone to enjoy.

When: Beginning October 20, 2025 through Spring 2026
What: Crews will be performing stem-density removal and related vegetation maintenance along sections of the Mission Reach to help manage flood risk and protect surrounding infrastructure. Some trails or segments may be closed temporarily while work is underway.
Why: Removing excess stems that naturally establish along the river helps maintain stormwater conveyance, reduces flood risk, and protects public infrastructure while allowing grassland and native vegetation to recover and thrive.
What to expect:

  • Limited trail closures and intermittent work zones.
  • Crews and equipment working near the riverbanks during daytime hours.
  • Parking areas remain open, but visitors may see signage and temporary barriers.

Questions? Call the San Antonio River Authority at (210) 227-1373 or visit https://www.sariverauthority.org/services/river-health/ecosystems/.

Thank you for your patience while we keep the Mission Reach safe, clean, and enjoyable.

San Pedro Creek Culture Park

The east bank trail along San Pedro Creek will be temporarily closed between the upper trail at Cameron St. and the lower trail at two access points.

Closure details:

  • The first closure will impact the connector from the upper trail near West Houston St. to the south lower San Pedro Creek trail.
  • Once work at this location is complete and the trail reopens, construction will shift to the second closure area between the upper and lower trails on the opposite side of the green space.

Please follow posted signage and plan alternate routes. We appreciate your patience as this work is completed.

Closed areas around San Pedro Creek Culture Park

The Brackenridge Trail

Trail Lighting Notice – Brackenridge Park Trail

Due to an electrical issue, lighting is currently out along the north portion of the trail, from the Josephine Street inlet to just past Highway 281 within the Brackenridge Park Trail. Our team is actively working to correct the issue and expects repairs to be completed by the end of business tomorrow.

We apologize for any inconvenience this may cause and appreciate your patience as we work to restore lighting. Please use caution when traveling through this area, especially during evening hours.

Trail Closure Alert – Calder Alley, San Pedro Creek

Maintenance work will be done in Calder Alley starting Wednesday, September 18, 2025.

  • Trails will remain open during this work.
  • One bench at a time will be temporarily barricaded while improvements are completed.
  • There may be occasional contractor pickups in the area.

We appreciate your patience as we continue to maintain and improve San Pedro Creek for all to enjoy!

SASPAMCO Paddling Trail

The SASPAMCO paddling trail is open from River Crossing Park to Helton Nature Park.
*Please Note: Paddling Trail from Helton Nature Park to HWY 97 is still closed due to blockages. 

SASPAMCO Paddling Trail Temporarily Closed

Staff have removed two large log jams just downstream of Helton Nature Park, keeping the southern portion of the SASPAMCO Paddling Trail temporarily closed. Staff are working to contact adjacent landowners to support a land-based removal solution.

Goliad Paddling Trail Alert

NOTICE: HWY 59 Landing Site Closed

Due to TxDOT construction on the HWY 59 Bridge, the HWY 59 landing site is closed until further notice. However, the Goliad Paddling Trail remains open, and paddlers can still access the river at the Riverdale, Ferry Street, and Goliad State Park landings.

Please plan accordingly and check back for updates.

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