Zulian Viviane, Blight Louise K, Osborne Jon, Smith Adam C, Norris Andrea R, Golat Rebecca, De Groot Krista L
Department of Biological Sciences, Clemson University, Clemson, SC, United States of America.
School of Environmental Studies, University of Victoria, Victoria, British Columbia, Canada.
PeerJ. 2025 Aug 29;13:e19943. doi: 10.7717/peerj.19943. eCollection 2025.
Bird-window collisions are a significant and growing threat to birds, but the issue is still understudied in many geographical areas and stages of the avian annual life cycle. The mountainous topography and numerous distinct biogeoclimatic zones along the Pacific coast of Canada and the United States may result in regional and seasonal differences in collision mortality and species vulnerability to collisions. We surveyed daily for evidence of bird-window collisions over six 21-day periods in fall, early winter, and late winter between 2019 and 2022 at a university campus in southwestern British Columbia, Canada, and assessed individual species' vulnerability to collisions by examining whether species-specific collision rates were disproportionate to their local abundance. We accounted for poor detectability of some species in fall, by integrating point count data from our study site with mist net capture data from a nearby banding station to improve abundance estimates. Collision mortality peaked in fall, but early winter collision mortality was significantly higher than in the later winter months, potentially due to movements of altitudinal migrants into our low-elevation study area in early winter. We estimated that an average of 885-1,342 (median = 1,095) birds are killed at 51 buildings campus-wide each year between September 15 and February 10, the peak fall migration wintering period. Forest birds, particularly species that switch to highly frugivorous diets in fall and winter, were most vulnerable to collisions across the seasons studied. Non-breeding season mortality due to collisions may be substantial for these species, particularly when considering cumulative mortality across the entire non-breeding period. The potential role of collision mortality in species declines should be further explored by assessing collision frequency and species vulnerability across life cycle stages in other geographical locations, and through improved data on migratory connectivity and linkages between declining breeding populations and non-breeding season mortality.
鸟类与窗户碰撞对鸟类构成了重大且日益严重的威胁，但在许多地理区域以及鸟类年度生命周期的各个阶段，这一问题仍未得到充分研究。加拿大和美国太平洋沿岸的山地地形以及众多独特的生物地理气候带，可能导致碰撞死亡率以及物种易受碰撞影响的程度存在区域和季节性差异。2019年至2022年期间，我们在加拿大不列颠哥伦比亚省西南部的一个大学校园，于秋季、初冬和冬末的六个21天时间段内，每日调查鸟类与窗户碰撞的证据，并通过检查特定物种的碰撞率是否与其当地丰度不成比例，来评估各个物种易受碰撞影响的程度。为了弥补秋季某些物种难以被发现的问题，我们将研究地点的点计数数据与附近环志站的雾网捕获数据相结合，以改进丰度估计。碰撞死亡率在秋季达到峰值，但初冬的碰撞死亡率明显高于冬末几个月，这可能是由于海拔迁徙鸟类在初冬进入我们低海拔的研究区域。我们估计，在9月15日至2月10日（秋季迁徙越冬高峰期）期间，校园内51栋建筑每年平均有885 - 1342只（中位数 = 1095）鸟类死亡。在整个研究季节中，森林鸟类，特别是那些在秋冬季节转向高度食果性饮食的物种，最容易受到碰撞影响。对于这些物种而言，碰撞导致的非繁殖季节死亡率可能相当可观，尤其是考虑到整个非繁殖期的累积死亡率时。应通过评估其他地理位置整个生命周期阶段的碰撞频率和物种易受影响程度，并通过改善关于迁徙连通性以及数量下降的繁殖种群与非繁殖季节死亡率之间联系的数据，进一步探讨碰撞死亡率在物种数量下降中的潜在作用。
