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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. Refuge staff constructed fences of 0.9-m-high, 0.32–0.64-cm mesh hardware cloth, with 15.2-m-long sides, and staked at the bottom to discourage predators from going under the fence. Workers placed fences around nests at a mean of 3.2 d of incubation. Eighty-two percent of fenced nests were successful vs. 12% for unfenced nests. Daily survival rate 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 daily survival rate and proportion of abandoned nests. The median proportion of eggs that hatched from successful nests was 6% higher for larger fences vs. 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. |
