Recommendation 20221010-007: Congress Ave Bats — original pdf

Recommendation

ANIMAL ADVISORY COMMISSION RECOMMENDATION 20221010-007 Date: 10/11/22 Colony Subject: Recommended Action Concerning the Congress Avenue Bridge Mexican Free-tail Bat Motioned By: Dr. Paige Nilson Seconded By: Beatriz Dulzaides Recommendation: 1. We recommend that the City of Austin posts a QR code prominently on the east side of both ends of the Congress Ave. bridge (and possibly at other locations), scannable by a smart phone, that links to a City website where detailed information about Austin’s bat colony can be provided. 2. We recommend that the dysfunctional string of lights on the western side of the Congress Ave. bridge be removed. This structure is a hazard to bats, particularly young bats, as they start their nightly flights for food (this may have already been done). 3. We recommend that Merlin Tuttle’s Bat Conservation specifically be consulted concerning the design and placement of any publicly accessible bat-viewing areas being considered. 4. We recommend that as soon as The Statesman PUD plans become finalized and the positioning of any proposed bat-viewing areas or decks has been determined, the City judiciously trims, as necessary, some of the trees along Lady Bird Lake for better public bat- viewing. 5. Vegetation beneath the bats’ roosting spaces at the extreme south end of the bridge should never be permitted to grow more than one meter tall. Bats will abandon this area if vegetation is permitted to grow much taller. 6. Currently, there is erosion damage to the Trail under the south end of the bridge from stormwater flow. There is a need for some kind of rainwater detention structure to be built on the uphill side of the Trail that overflows into culverts beneath the path and into the Lake to control this flooding and minimize erosion. Description of Recommendation to Council: 1. The linked website should contain information about bat viewing opportunities, safety around bats, and what to do about injured bats. We further recommend that for detailed biological and historical information about Austin bats, including seasonal cycles that affect viewing opportunities, bat behavior, and the ecological significance of this colony, the City site should be linked to a site specifically designed and frequently updated for this detailed information by Merlin Tuttle’s Bat Conservation (MTBC), which has volunteered their services for this task. 2. This recommendation is self-explanatory. 3. This recommendation is self-explanatory. 4. Trees do not need to be removed in this trimming, but some of the lower tree branches could be trimmed for better sight lines, depending on the location of the bat-viewing areas. 5. A more sophisticated planting could be designed for this area, as any tall vegetation beneath the bridge that interferes with the bats will also demand more maintenance. 6. This project will probably be best handled by a collaboration between the Watershed Protection Department and the Austin Trail Conservancy. 1 of 2 Rationale: Austin’s Mexican free-tail bat colony is the most famous urban bat colony in the USA. As such, it is easily worth in excess of $10 million yearly to Austin downtown businesses from the tourists who come from all over the world to experience an evening emergence. In addition, the most beautiful views of Austin are from Lady Bird Lake in the evenings, which is featured on any of our many bat cruises. Life is tenacious, yet fragile. We should not take this natural treasure for granted. Now is the time to monitor and upgrade Austin’s bat experience for the future of our City. Vote For: 7 Against: 0 Abstain: 0 Absent: 6 Attest: 2 of 2