Avian communities play a pivotal role in Arctic ecosystems and birds have become the key model taxa for climate change research. Due to funding priorities, Arctic passerines have been studied less intensively than waterfowl and shorebirds. In our study, we aim to partly fill this gap and look at the change in passerine community species composition in the Chaun River Delta in Northeast Siberia (68.81° N, 170.62° E) between 1970–1980 and 2002–2019. We restricted our comparison to 16 tundra-dwelling species associated with grass and shrub tundra habitats. During the first period, 12 passerine species were reported and by the end of the last period, 14 species. Our observations show that four species of shrub-dwelling passerines, the Dusky Warbler (Phylloscopus fuscatus), two species of Turdus thrushes, and the Siberian Rubythroat (Calliope calliope), have joined the local community. Additionally, one Turdus thrush species increased in numbers. The only passerine species that used to be common in the 70’s and rare in the 2000s is the Lapland Bunting (Calcarius lapponicus). Yellow-breasted Bunting (Emberiza aureola, vagrant in 70’s) and Siberian Chiffchaff (Phylloscopus tristis, rare breeder in 70’s) have not been recorded during the most recent period. At the same time, there was no observed change in abundance for eight species of songbirds. The results of supervised satellite image classification did not detect any local-scale increase of shrub cover in our study site. However, a broad-scale assessment of vegetation change using NDVI suggests substantial greening or ‘shrubification’ across the region. We speculate that it promotes region-wide increases and range expansion of some shrub-dwelling species, recorded in our study.

鸟类群落在北极生态系统中发挥着关键作用，鸟类已成为气候变化研究的关键模型类群。由于资金优先考虑，北极雀鸟的研究不如水禽和滨鸟那么深入。在我们的研究中，我们旨在部分填补这一空白，并研究 1970-1980 年和 2002-2019 年间西伯利亚东北部 Chaun 河三角洲（北纬 68.81°，东经 170.62°）雀类群落物种组成的变化。我们将比较限制在与草和灌木苔原栖息地相关的 16 种苔原栖息物种。在第一阶段，报告了 12 种雀形目，到最后阶段结束时，报告了 14 种。我们的观察显示，四种栖息于灌木的雀形目雀类、暗莺 ( Phylloscopus fuscatus )、两种鸬鹚画眉，和西伯利亚红喉（Calliope calliope ），已经加入了当地社区。此外，一种Turdus画眉物种的数量有所增加。唯一曾在 70 年代常见而在 2000 年代稀有的雀形目种类是拉普兰鹀 ( Calcarius lapponicus)。黄胸鹀 ( Emberiza aureola , 70 年代流浪) 和西伯利亚雪夫 ( Phylloscopus tristis, 70 年代的稀有种鸡）在最近一段时间内没有记录。同时，没有观察到八种鸣禽的丰度变化。监督卫星图像分类的结果没有检测到我们研究地点的灌木覆盖在局部范围内增加。然而，使用 NDVI 对植被变化进行的大规模评估表明该地区出现了大量绿化或“灌木化”。我们推测它促进了我们研究中记录的一些灌木栖息物种的区域范围内的增加和范围的扩大。