British Trust for Ornithology Scotland, Stirling University Innovation Park, Beta Centre (Unit 15), Stirling, FK9 4NF, UK.
British Trust for Ornithology, The Nunnery, Thetford, IP24 2PU, Norfolk, UK.
Proc Biol Sci. 2023 Jun 28;290(2001):20230580. doi: 10.1098/rspb.2023.0580. Epub 2023 Jun 21.
Failure to adapt migration timing to changes in environmental conditions along migration routes and at breeding locations can result in mismatches across trophic levels, as occurs between the brood parasitic common cuckoo and its hosts. Using satellite tracking data from 87 male cuckoos across 11 years, we evaluate why the cuckoo has not advanced its arrival to the UK. Across years, breeding ground arrival was primarily determined by timing of departure from stopover in West Africa before northward crossing of the Sahara. Together with high population synchrony and low apparent endogenous control of this event, this suggests that a seasonal ecological constraint operating here limits overall variation in breeding grounds arrival, although this event was itself influenced by carry-over from timing of arrival into tropical Africa. Between-year variation within individuals was, in contrast, mostly determined by northward migration through Europe, probably due to weather conditions. We find evidence of increased mortality risk for (a) early birds following migration periods positively impacting breeding grounds arrival, and (b) late birds, possibly suffering energy limitation, after departure from the breeding grounds. These results help identify areas where demands of responding to global change can potentially be alleviated by improving stopover quality.
未能根据迁徙路线和繁殖地的环境条件变化调整迁徙时间，可能导致营养级之间的不匹配，就像寄生性的普通杜鹃鸟与其宿主之间那样。利用 11 年间 87 只雄性杜鹃的卫星跟踪数据，我们评估了杜鹃为何未能提前到达英国。多年来，繁殖地的到达主要取决于从西非中途停留地出发向北穿越撒哈拉沙漠的时间。加上种群高度同步和对该事件的内在控制作用较低，这表明季节性生态限制在这里限制了繁殖地到达的整体变化，尽管这一事件本身受到进入热带非洲时间的影响。相比之下，个体内的年际差异主要取决于通过欧洲的向北迁徙，这可能是由于天气条件造成的。我们发现，（a）在迁徙期间积极影响繁殖地到达的早到鸟和（b）在离开繁殖地后可能因能量限制而迟到的鸟的死亡风险增加。这些结果有助于确定在哪些领域，通过改善中途停留地的质量，可以缓解应对全球变化的需求。
