Woody encroachment affects wildlife distributions and predator-prey dynamics in North American grasslands. In 2015–2016, we studied how vegetation influences avian nest predators and predation rates in South Texas’ semiarid grasslands. Monitoring 253 nests of 17 bird species, we categorized nests by size and structure and used infrared cameras at 107 sites. Logistic regression showed that a 10% increase in shrub cover significantly reduced nest success for medium-sized cup nests and increased snake predation by 6.7%. With snakes as the primary predator (59% of recorded cases), our findings inform grassland bird management and strategies to improve nest success.