Global environmental changes are predicted to lead to warmer average temperatures and more extreme weather events thereby affecting wildlife population dynamics by altering demographic processes. Extreme weather events can reduce food resources and mortality, but the contribution of such events to demographic processes are poorly understood. Estimates of season-specific survival probabilities are crucial for understanding mechanisms underlying annual mortality. However, only few studies have investigated survival at sufficient temporal resolution to assess the contribution of extreme weather events. Here, we analysed biweekly survival probabilities of 307 radio-tracked juvenile little owls (Athene noctua) from fledging to their first breeding attempt in the following spring. Biweekly survival probabilities were lowest during the first weeks after fledging in summer and increased over autumn to winter. The duration of snow cover in winter had a strong negative effect on survival probability, while being well fed during the nestling stage increased survival during the first weeks after fledging and ultimately led to a larger proportion of birds surviving the first year. Overall annual survival probability over the first year varied by 34.3 % between 0.117 (95 % credible interval 0.052 – 0.223) and 0.178 (0.097 – 0.293) depending on the severity of the winter, and up to 0.233 (0.127 – 0.373) for well-fed fledglings. The season with the lowest survival was the post-fledging period (0.508; 0.428 – 0.594) in years with mild winters, and the winter in years with extensive snow cover (0.481; 0.337 – 0.626). We therefore show that extreme weather events reduced the proportion of first-year survivors. Increasingly warmer winters with less snow cover may therefore increase annual survival probability of juvenile little owls in central Europe, but environmental changes reducing food supply during the nestling period can have similarly large effects on annual juvenile survival and therefore the viability of populations.

Parental investment theory proposes two non-mutually exclusive hypotheses to explain variation in anti-predator behaviour in relation to the age of offspring: the “reproductive value of offspring” hypothesis and the “harm to offspring” hypothesis. The relative importance of the two factors underlying the hypotheses, reproductive value and harm, may change depending on environmental conditions such as food availability. To test the relative importance of the two hypotheses under different food conditions, we conducted a supplementary feeding experiment in red kite (Milvus milvus) breeding pairs and used a live eagle owl (Bubo bubo) as decoy nest predator to trigger anti-predator behaviour. We used time-to-capture in mist nets mounted next to the decoy predator as proxy for mobbing intensity. Under natural food conditions we found a nearly constant mobbing intensity throughout the entire nestling period. However, under food-enhanced conditions mobbing intensity was reduced in parents with young nestlings and increased in parents with old nestlings. These results suggest greater importance of the “reproductive value of offspring” hypothesis in situations of favourable food availability. Moreover, mobbing intensity depended on brood size and weather conditions. The results suggest that parental anti-predator investment increases with the reproductive value of the brood under favourable breeding conditions, but that this pattern is adjusted to the current context, including the vulnerability of the brood and environmental conditions.

Floral plantings are promoted to foster ecological intensification of agriculture through provisioning of ecosystem services. However, a comprehensive assessment of the effectiveness of different floral plantings, their characteristics and consequences for crop yield across global regions is lacking. Here we quantified the impacts of flower strips and hedgerows on pest control and pollination services in adjacent crops using a global dataset of 529 sites. Flower strips, but not hedgerows, enhanced pest control services in adjacent fields by 16% on average. However, effects on crop pollination and yield were more variable. Our synthesis identifies several important drivers of variability in effectiveness of plantings: pollination services declined exponentially with distance from plantings, and perennial and older flower strips with higher flowering plant diversity enhanced pollination more effectively. These findings provide promising pathways to optimize floral plantings to more effectively contribute to ecosystem service delivery and ecological intensification of agriculture in the future.