Each year, billions of birds migrate across the continents by day and night through airspaces increasingly altered by human activity, resulting in the deaths of millions of birds every year through collisions with man‐made structures. To reduce these negative impacts on wildlife, forecasts of high migration intensities are needed to apply mitigation actions. While existing weather radar networks offer a unique possibility to monitor and forecast bird migration at large spatial scales, forecasts at the fine spatial scale within a complex terrain, such as the mountainous Swiss landscape, require a small‐scale network of ornithological radars. Before attempting to build such a network, it is crucial to first investigate the consistency of the migratory flow across space and time. In this study, we simultaneously operated three ornithological radar systems across the Swiss lowlands to assess the spatio‐temporal consistency of diurnal and nocturnal bird movements during the spring and autumn migration season. The relative temporal course of migration intensities was generally consistent between sites during peak migration, in particular for nocturnal movements in autumn, but absolute intensities differed greatly between sites. Outside peak migration, bird movement patterns were much less consistent and, unexpectedly, some presumably non‐migratory bird activity achieved intensities close to peak migration intensities, but without spatial correlations. Only nocturnal migration intensity in autumn could be predicted with consistently high accuracy, but including parameters of atmospheric conditions in the model improved predictability of diurnal movements considerably. Predictions for spring were less reliable, probably because we missed an important part of the migration season. Our results show that reliable forecasts of bird movements within a complex terrain call for a network of year‐round bird monitoring systems, whereas accurate information of atmospheric conditions can help to limit the number of measurement points.

中文翻译：

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瑞士低地鸟类迁徙时空格局的一致性

每年，数十亿只鸟类通过人类活动逐渐改变的空域在白天和黑夜之间穿越大陆，每年与人造结构碰撞导致数百万只鸟类死亡。为了减少这些对野生动植物的负面影响，需要采用缓解措施来预测高迁移强度。尽管现有的天气雷达网络提供了在较大的空间规模上监视和预测鸟类迁徙的独特可能性，但在复杂地形（例如瑞士山地景观）内的精细空间范围内进行预测，却需要小型的鸟类学雷达网络。在尝试建立这样的网络之前，至关重要的是首先研究跨时空迁移流的一致性。在这个研究中，我们同时在瑞士低地上运行了三个鸟类学雷达系统，以评估春季和秋季迁徙季节白天和夜间鸟类活动的时空一致性。高峰迁移期间，站点之间的迁移强度的相对时间过程通常是一致的，特别是对于秋季的夜间活动，但站点之间的绝对强度差异很大。在高峰迁徙之外，鸟类的活动方式不一致得多，而且出乎意料的是，一些非迁徙鸟类的活动强度接近高峰迁徙强度，但没有空间相关性。始终能够以很高的精度预测秋天的夜间迁徙强度，但在模型中包括大气条件参数后，大大提高了昼夜运动的可预测性。对春季的预测不太可靠，可能是因为我们错过了移徙季节的重要部分。我们的结果表明，对复杂地形中鸟类运动的可靠预测需要建立全年的鸟类监测系统网络，而准确的大气状况信息可以帮助限制测量点的数量。