Use of Predator-Deterrent Fences to Increase Attwater's Prairie-Chicken Nest Success

We retrospectively evaluated 20 y of using predator-deterrent fences to mitigate unusually high nest predation for the critically endangered Attwater's prairie-chicken Tympanuchus cupido attwateri at the Attwater Prairie Chicken National Wildlife Refuge. Fences were constructed of 0.9-m high, 0.32-0.64-cm mesh hardware cloth, with 15.2-m long sides, and were staked at the bottom to discourage predators from going under the fence. Fences were placed around nests at = 3.2 d of incubation. Eighty-two percent of fenced nests were successful versus 12% for unfenced nests. Daily survival rate (DSR) increased from 0.9159 for unfenced nests in 1997-2011 to 0.9916 for fenced nests during 2000-2019. Fencing did not increase abandonment or reduce the proportion of eggs that hatched in successful nests. After 2012, we reduced fence sides from 15.2 m to 7.6 m in length. Larger and smaller fences were equally effective with respect to DSR and proportion of nests that were abandoned. The median proportion of eggs that hatched from successful nests was 6% higher for larger fences versus smaller fences, but this difference was not statistically significant. Predator-deterrent fences substantially increased Attwater's prairie-chicken nesting success in this study, and may represent a viable management strategy for increasing nesting success for other populations of ground-nesting birds with high conservation value.