Powerline collisions have been identified on Kaua'i as a potential contributing factor to the large-scale decline of both Hawaiian Petrel (Pterodroma sandwichensis) and Newell's Shearwater (Puffinus newelli), but the scale of the powerline collision problem is unknown. From 2012 to 2020 we conducted observations for seabird powerline collisions across Kaua'i, documented grounded seabirds, and assessed crippling and environmental biases - both poorly studied facets of powerline collision research. We directly observed 121 powerline collisions and detected 89 grounded seabirds. While some collisions resulted in birds falling lifelessly out of the sky, most resulted in seabirds flying or gliding outside of the search area. This means that traditional ground searches would underestimate total collisions by 78-88% if not accounting for crippling bias. We tested environmental bias by comparing our ability to conduct searches for grounded birds, "searchability", across multiple variables. Environmental bias resulted in significant reductions in searchability across regions, environment types, and powerline heights. Furthermore, observed collision rates were significantly higher at powerlines that had very low to zero searchability. Forty-three percent of observed collisions occurred at unsearchable powerlines (mainly spanning steep valleys), equating to an estimated 3170 seabird collisions that could not be detected through ground searches. We detected powerline collisions in every region of Kaua'i, in every environment type, and at all powerline heights monitored. Our results show that crippling bias and environmental bias are the mechanisms that concealed the geographic distribution of collisions and the scale of the powerline problem from grounded bird searches, ultimately preventing the detection of thousands of collisions. The data collected for this study are critical for assessing the scale of seabird powerline collisions and quantifying the biases inherent in traditional ground searches.

中文翻译：

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纽维尔的Shearwater和Hawaiian Petrel电力线碰撞研究中的碰撞后影响，残废偏见和环境偏见

在考艾岛上已发现电力线碰撞是夏威夷海燕（Pterodroma sandwichensis）和纽维尔的Shearwater（Puffinus newelli）大规模下降的潜在因素，但电力线碰撞问题的规模尚不清楚。从2012年到2020年，我们对整个Kaua'i的海鸟电力线碰撞进行了观测，记录了接地的海鸟，并评估了残骸和环境偏差-两者对电力线碰撞研究的研究都很少。我们直接观察到121条电力线碰撞，并发现了89只接地海鸟。虽然有些碰撞导致鸟类从空中坠落，但大多数导致海鸟在搜索区域外飞行或滑行。这意味着如果不考虑残障，传统的地面搜索将低估总碰撞量78-8％。我们通过比较我们在多个变量中搜索地面鸟类的能力（“可搜索性”）来测试环境偏见。环境偏见导致跨地区，环境类型和电力线高度的可搜索性大大降低。此外，在具有极低至零可搜索性的电力线处，观察到的碰撞率明显更高。观察到的碰撞中有百分之四十三发生在无法搜索的电力线（主要跨越陡峭的山谷），相当于估计3170笔海鸟碰撞无法通过地面搜索发现。我们在考艾岛的每个区域，每种环境类型中检测到电力线碰撞，并在所有电力线高度进行监控。我们的结果表明，残障和环境偏见是掩盖碰撞的地理分布和电力线问题规模的机制，可从地面鸟类搜寻中隐瞒，最终阻止了数千次碰撞的检测。这项研究收集的数据对于评估海鸟电力线碰撞的规模以及量化传统地面搜索固有的偏见至关重要。