1. Arctic-breeding goose populations have increased in recent decades and their expansion into agricultural areas has caused increasing conflict with farmers due to the damage they cause. Lethal control and scaring are common management strategies of conflict mitigation. Management typically focuses on local/national scales, making addressing the impact of localised control on the wider population challenging, particularly when populations move over large areas and cross international borders.2. We construct an integrated population model (IPM) to assess the cumulative impact of all shooting harvest (hunting and derogation shooting) on the Greenland barnacle goose, Branta leucopsis. We use data from monitoring schemes throughout the migratory flyway and use population projections to evaluate the impact of potential future shooting strategies on abundance.3. Our model suggests flyway abundance has declined since its 2012 peak, consistent with an increase in harvest rate and low productivity. Harvest rate increase was most pronounced on Islay (rising from 2% to 7% from 2011 to 2017), suggesting this was a probable cause of flyway abundance decline. 4. Islay abundance has declined since derogation shooting began in 2000, while abundance at other wintering sites has increased. This may indicate that declines in Islay abundance may be due to both shooting mortality and emigration from Islay.5. Should future flyway-level harvest rates increase, further declines in abundance could be expected, and are likely to be more pronounced if harvests are extended to the entire winter range. Conversely, should harvest rates decline, an increase in abundance is predicted. Projections can therefore be used to allocate flywaylevel harvest rates to alleviate local pressure without hindering flyway-level management objectives.6. Synthesis and applications. Our findings demonstrate the impact of local harvests on global abundance, emphasising the importance of internationally coordinated monitoring and management strategies of migratory species. IPMs provide a | 765

Lead is a toxic heavy metal that when ingested can cause death or sub‐lethal fitness effects. Despite its toxicity, it is still widely used in recreational and management shooting globally. To reduce the impacts of lead on wildfowl, recent European Union legislation has banned the use of lead shot in and around wetlands from 2023. Understanding the effectiveness of such mitigation is vital to inform future policy. On Islay, Scotland, the licensed shooting of Barnacle Geese Branta leucopsis to reduce agricultural damage has adhered to the ban on use of lead shot over Ramsar‐designated wetlands legislated in Scotland in 2004. On average 2380 lead cartridges were fired annually between 2005 and 2020 outside designated wetlands, where Barnacle Geese and other wildfowl forage. From faecal samples, it is possible to infer whether birds have ingested lead and are therefore potentially suffering from lead poisoning. After sampling faeces from Barnacle Geese (n = 193) and Greenland White‐fronted Geese Anser albifrons flavirostris (n = 150) we found only four (1.2%) faecal samples with elevated lead levels that may be indicative of lead shot ingestion. Further post‐mortem examinations (n = 102 Barnacle Geese only) and X‐ray of live birds (n = 293) revealed similarly low levels of shot ingestion in both species (post‐mortem < 4%, and X‐ray < 2%), corroborating findings from faecal sample analysis. When subsequently accounting for limited shot retention time within individuals, the proportion of each population ingesting a single lead shot over a winter was estimated at a maximum of 9.4% (Barnacle Geese) and 16.8% (White‐fronted Geese). We propose that high compliance with the ban on using lead shot over wetlands because of carefully controlled shooting management on Islay has led to relatively low instantaneous ingestion rates, probably resulting in minimal lead poisoning mortality. However, ingestion was not eliminated and the potential fitness effect of chronic lead poisoning in both goose populations therefore persists, although use of lead shot in organized shooting has subsequently been discontinued. Recent European Union bans on lead shot use over wetlands may reduce lead ingestion in waterfowl if compliance rates are high, but as foraging often occurs outside wetlands (as in this study), further restrictions including use on other key foraging sites may help to further mitigate the risk of lead poisoning in waterfowl.