According to the Cornell Lab of Ornithology's eBird database, which collects observations from birdwatchers across North America, the Red-Bellied Woodpecker is found in all counties of Tennessee. Based on eBird data, the species has been observed in high abundances throughout the state, suggesting a sizable population.
However, it's important to note that bird populations can vary over time, and local factors such as habitat quality and food availability can influence the density of Red-Bellied Woodpeckers in specific areas. For more up-to-date and precise information on the population of Red-Bellied Woodpeckers in Tennessee, it's recommended to consult with local ornithologists, wildlife agencies, or research institutions that conduct regular bird surveys or population monitoring in the state.