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SummaryRecent work suggests that the environment experienced in early life can alter life histories in wild populations [1–5], but our understanding of the processes involved remains limited [6, 7]. Since anthropogenic environmental change is currently having a major impact on wild populations [8], this raises the possibility that life histories may be influenced by human activities that alter environmental conditions in early life. Whether this is the case and the processes involved remain unexplored in wild populations. Using 23 years of longitudinal data on the Mauritius kestrel (Falco punctatus), a tropical forest specialist, we found that females born in territories affected by anthropogenic habitat change shifted investment in reproduction to earlier in life at the expense of late life performance. They also had lower survival rates as young adults. This shift in life history strategy appears to be adaptive, because fitness was comparable to that of other females experiencing less anthropogenic modification in their natal environment. Our results suggest that human activities can leave a legacy on wild birds through natal environmental effects. Whether these legacies have a detrimental effect on populations will depend on life history responses and the extent to which these reduce individual fitness.

Summary Because biological systems are complex, management interventions occasionally have unintended adverse consequences. For example, attempts to control bovine tuberculosis (TB) by culling badgers Meles meles have, under some circumstances, inadvertently increased cattle TB risks. Such harmful effects occur because culling profoundly alters badger movement behaviour, increasing pathogen transmission both between badgers and from badgers to cattle. It has recently been suggested that another TB management tool, badger vaccination with Bacillus Calmette Guerin, might provoke similar behavioural changes and hence similar harmful effects for cattle. We therefore took advantage of an existing project, which monitored 54 GPS‐collared badgers across four study sites in southwest Britain, to explore whether vaccination, or live trapping to administer vaccine, influenced badger movement behaviour. We detected no significant effects of either vaccination or trapping on badgers’ monthly home range size, nightly distance travelled, or frequency of trespassing in neighbouring territories. The estimated effect of vaccination on badger home range size [2% reduction, 95% confidence interval (CI) 18% reduction – 17% increase] was statistically non‐significant, but significantly smaller than that associated with both widespread (180% increase, 95% CI 70–362% increase; P < 0·001) and localised badger culling (74% increase, 95% CI 4–191% increase; P = 0·038). Synthesis and applications. In contrast with culling, live trapping and vaccinating badgers did not measurably alter their movement behaviour, fuelling optimism that vaccination might contribute positively to cattle tuberculosis control. Our study illustrates how existing monitoring can be exploited to assess potentially adverse effects of wildlife management.

Habitat conversion for agriculture is a major driver of biodiversity loss, but our understanding of the demographic processes involved remains poor. We typically investigate the impacts of agriculture in isolation even though populations are likely to experience multiple, concurrent changes in the environment (e.g. land and climate change). Drivers of environmental change may interact to affect demography, but the mechanisms have yet to be explored fully in wild populations.Here, we investigate the mechanisms linking agricultural land use with breeding success using long-term data for the formerly Critically Endangered Mauritius kestrel Falco punctatus, a tropical forest specialist that also occupies agricultural habitats. We specifically focused on the relationship between breeding success, agriculture and the timing of breeding because the latter is sensitive to changes in climatic conditions (spring rainfall) and enables us to explore the interactive effects of different (land and climate) drivers of environmental change.Breeding success, measured as egg survival to fledging, declines seasonally in this population, but we found that the rate of this decline became increasingly rapid as the area of agriculture around a nest site increased. If the relationship between breeding success and agriculture was used in isolation to estimate the demographic impact of agriculture, it would significantly under-estimate breeding success in dry (early) springs and over-estimate breeding success in wet (late) springs.Analysis of prey delivered to nests suggests that the relationship between breeding success and agriculture might be due, in part, to spatial variation in the availability of native, arboreal geckos.Synthesis and applications. Agriculture modifies the seasonal decline in breeding success in this population. As springs are becoming wetter in our study area and since the kestrels breed later in wetter springs, the impact of agriculture on breeding success will become worse over time. Our results suggest that forest restoration designed to reduce the detrimental impacts of agriculture on breeding may also help reduce the detrimental effects of breeding late due to wetter springs. Our results therefore highlight the importance of considering the interactive effects of environmental change when managing wild populations.