Department of Biology, Augustana College, Rock Island, Illinois, United States of America.
PLoS One. 2013;8(1):e53371. doi: 10.1371/journal.pone.0053371. Epub 2013 Jan 9.
Collisions with windows are an important human-related threat to birds in urban landscapes. However, the proximate drivers of collisions are not well understood, and no study has examined spatial variation in mortality in an urban setting. We hypothesized that the number of fatalities at buildings varies with window area and habitat features that influence avian community structure. In 2010 we documented bird-window collisions (BWCs) and characterized avian community structure at 20 buildings in an urban landscape in northwestern Illinois, USA. For each building and season, we conducted 21 daily surveys for carcasses and nine point count surveys to estimate relative abundance, richness, and diversity. Our sampling design was informed by experimentally estimated carcass persistence times and detection probabilities. We used linear and generalized linear mixed models to evaluate how habitat features influenced community structure and how mortality was affected by window area and factors that correlated with community structure. The most-supported model was consistent for all community indices and included effects of season, development, and distance to vegetated lots. BWCs were related positively to window area and negatively to development. We documented mortalities for 16/72 (22%) species (34 total carcasses) recorded at buildings, and BWCs were greater for juveniles than adults. Based on the most-supported model of BWCs, the median number of annual predicted fatalities at study buildings was 3 (range = 0-52). These results suggest that patchily distributed environmental resources and levels of window area in buildings create spatial variation in BWCs within and among urban areas. Current mortality estimates place little emphasis on spatial variation, which precludes a fundamental understanding of the issue. To focus conservation efforts, we illustrate how knowledge of the structural and environmental factors that influence bird-window collisions can be used to predict fatalities in the broader landscape.
窗户碰撞是城市景观中鸟类面临的一个重要人为威胁。然而，导致碰撞的直接原因还没有被很好地理解，也没有研究检验过城市环境中死亡率的空间变化。我们假设建筑物上的死亡数量随窗户面积以及影响鸟类群落结构的生境特征而变化。2010 年，我们在美国伊利诺伊州西北部的一个城市景观中记录了鸟类与窗户的碰撞（BWCs），并对 20 座建筑物的鸟类群落结构进行了描述。对于每座建筑物和每个季节，我们进行了 21 次每日尸体调查和 9 次点计数调查，以估计相对丰度、丰富度和多样性。我们的抽样设计受到了实验性估计尸体持久性和检测概率的启发。我们使用线性和广义线性混合模型来评估生境特征如何影响群落结构，以及死亡率如何受到窗户面积以及与群落结构相关的因素的影响。最支持的模型对于所有群落指数都是一致的，包括季节、发展和与植被地段的距离的影响。BWCs 与窗户面积呈正相关，与发展呈负相关。我们记录了在建筑物上记录的 16/72（22%）种（34 个总尸体）的死亡情况，并且 BWCs 对幼鸟比成年鸟的影响更大。根据 BWCs 的最支持模型，研究建筑物每年预测的致命事件中位数为 3 个（范围为 0-52 个）。这些结果表明，在建筑物中分布不均的环境资源和窗户面积水平会导致城市内部和城市之间的 BWCs 存在空间变化。目前的死亡率估计很少强调空间变化，这使得对这一问题的基本理解变得不可能。为了集中保护工作，我们说明了影响鸟类与窗户碰撞的结构和环境因素的知识如何用于预测更广泛景观中的死亡率。
