Department of Biostatistics, University of Veterinary Medicine Budapest, Budapest, Hungary.
Evolutionary Ecology Group, Hungarian Department of Biology and Ecology, Babeş-Bolyai University, Cluj-Napoca, Romania.
Sci Rep. 2024 Oct 30;14(1):26055. doi: 10.1038/s41598-024-76845-5.
Climate change co-occurs with an advancement of avian breeding season (indexed as laying dates or fledging dates) in the temperate zone, suggesting a causality between them. Here, we investigate whether the long-term shifts in nestling (chick) ringing dates also mirror this phenomenon. This index is biased by inherent shortcomings, such as the non-independence of dates (in nestmates, colony members), poor accuracy (long period suitable for ringing), and strange shape of distributions. These shortcomings can be reduced by applying the median of annual ringing dates as an index of breeding phenology. The advantage of this index is that data are available for long periods and large sample sizes. By accepting certain compromise between statistical discipline and fieldwork realities, we examined changes in the breeding phenology of 9 bird species from 1951 to 2020 in Hungary. We found that the annual median of ringing dates advanced significantly (by 9-14 days) in the Black-headed Gull, Common Kestrel, Barn Swallow, Great Tit, and Eurasian Blue Tit. Contrarily, no significant (all P > 0.16) changes occurred in the case of the Common Tern, Black-crowned Night-heron, Common Buzzard, and Long-eared Owl. We also found that the proportion of Great Tits' second brood has been reduced in recent decades.
气候变化与温带地区鸟类繁殖季节（以产卵日期或育雏日期为指标）的提前同时发生，表明两者之间存在因果关系。在这里，我们研究了雏鸟（雏鸟）环志日期的长期变化是否也反映了这一现象。该指数存在固有缺陷，例如日期的非独立性（在巢内雏鸟、巢群成员中）、准确性差（环志的长周期）和分布形状奇特。通过应用年环志日期的中位数作为繁殖物候学指数，可以减少这些缺陷。该指数的优点是数据可用于长时间和大样本量。在接受统计纪律和实地工作实际之间的某些妥协的情况下，我们检查了 1951 年至 2020 年匈牙利 9 种鸟类繁殖物候学的变化。我们发现，黑头鸥、普通红隼、家燕、大山雀和普通蓝山雀的年度环志日期中位数显著提前（提前 9-14 天）。相反，普通燕鸥、黑冠夜鹭、普通鹰雕和长耳鸮的情况没有显著变化（所有 P>0.16）。我们还发现，近年来大山雀的第二窝雏鸟比例有所减少。
