Recent declines of many European bird species have been linked with various environmental changes, especially land-use change and climate change. Since the intensity of these environmental changes varies among different countries, we can expect geographic variation in bird population trends. Here, we compared the population trends of bird species among neighbouring countries within central Europe (Czech Republic, Denmark, Germany, Switzerland) between 1990 and 2016 and examined trait-associations with population trends at both national and international scales. We found that Denmark had the highest proportion of declining species while Switzerland had the lowest. Species associated with farmland had negative trends, but the effect size tended to differ among countries. A preference for higher temperature was positively associated with population trends and its effect size was similar among countries. Species that were increasing across all four countries were associated with forest; while species that were decreasing across all countries were long-distance migrants or farmland birds. Our results suggest that land-use change tends to be a more regionally variable driver of common bird population trends than climate change in central Europe. For species declining across all countries, international action plans could provide a framework for more efficient conservation. However, farmland birds likely need both, coordinated international action (e.g. through a green agricultural policy) to tackle their widespread declines as well as regionally different approaches to address varying national effect trajectories.

许多欧洲鸟类最近的减少与各种环境变化有关，尤其是土地利用变化和气候变化。由于这些环境变化的强度因国家而异，我们可以预期鸟类种群趋势的地理差异。在这里，我们比较了 1990 年至 2016 年间中欧邻国（捷克共和国、丹麦、德国、瑞士）的鸟类种群趋势，并在国家和国际尺度上检查了特征与种群趋势的关联。我们发现丹麦的物种减少比例最高，而瑞士的比例最低。与农田相关的物种有负面趋势，但各国之间的影响大小往往不同。对更高温度的偏好与人口趋势呈正相关，其影响大小在各国之间相似。所有四个国家都在增加的物种与森林有关；而所有国家都在减少的物种是长途迁徙或农田鸟类。我们的结果表明，与中欧的气候变化相比，土地利用变化往往是常见鸟类种群趋势的区域性变化驱动因素。对于所有国家都在减少的物种，国际行动计划可以为更有效的保护提供一个框架。然而，农田鸟类可能需要协调的国际行动（例如通过绿色农业政策）来解决它们的广泛下降，以及区域不同的方法来解决不同的国家影响轨迹。