Julia L. Newth

Potential hazard to human health from exposure to fragments of lead bullets and shot in the tissues of game animals

Background Lead is highly toxic to animals. Humans eating game killed using lead ammunition generally avoid swallowing shot or bullets and dietary lead exposure from this source has been considered low. Recent evidence illustrates that lead bullets fragment on impact, leaving small lead particles widely distributed in game tissues. Our paper asks whether lead gunshot pellets also fragment upon impact, and whether lead derived from spent gunshot and bullets in the tissues of game animals could pose a threat to human health. Methodology/Principal Findings Wild-shot gamebirds (6 species) obtained in the UK were X-rayed to determine the number of shot and shot fragments present, and cooked using typical methods. Shot were then removed to simulate realistic practice before consumption, and lead concentrations determined. Data from the Veterinary Medicines Directorate Statutory Surveillance Programme documenting lead levels in raw tissues of wild gamebirds and deer, without shot being removed, are also presented. Gamebirds containing ≥5 shot had high tissue lead concentrations, but some with fewer or no shot also had high lead concentrations, confirming X-ray results indicating that small lead fragments remain in the flesh of birds even when the shot exits the body. A high proportion of samples from both surveys had lead concentrations exceeding the European Union Maximum Level of 100 ppb w.w. (0.1 mg kg−1 w.w.) for meat from bovine animals, sheep, pigs and poultry (no level is set for game meat), some by several orders of magnitude. High, but feasible, levels of consumption of some species could result in the current FAO/WHO Provisional Weekly Tolerable Intake of lead being exceeded. Conclusions/Significance The potential health hazard from lead ingested in the meat of game animals may be larger than previous risk assessments indicated, especially for vulnerable groups, such as children, and those consuming large amounts of game.

Has winter body condition varied with population size in a long-distance migrant, the Bewick’s Swan (Cygnus columbianus bewickii)?

Assessments of body condition can provide useful information on changes in the state of individuals within a population, which may in turn help to inform conservation efforts. For example, decreases in body condition over time can indicate reduced food resources. Mass and skull length measures recorded for 195 adult and 467 first winter (cygnets) Bewick’s Swans (Cygnus columbianus bewickii) at wintering sites in the UK between winters 1966/1967 and 2017/2018 therefore were analysed to determine whether a ca. 40% decline in numbers in the Northwest European Bewick’s Swan population between 1995 and 2010 corresponded with poorer body condition from the mid-1990s onwards. Parents and siblings were known for all individuals, allowing us to account for shared genetic factors and rearing environment in our analysis. We used linear mixed-effects models and an information-theoretic approach to test different models of temporal variation in scaled body mass index (SBMI). Within our study population, although SBMI values varied both within and between years, we found no evidence of any directional trends in body condition. Of our competing time models of swan SBMI, a model in which age-specific body condition was constant over time received the greatest support in the data. Body condition was greater for adults than cygnets, but did not vary between sexes or wintering sites. Our findings suggest no connection between the recent declines in population size and body condition. Population decline is therefore unlikely to be caused by inadequate food supplies.

The status and distribution of summering Greylag Geese Anser anser in Scotland, 2008–09

Capsule Summering Greylag Geese Anser anser are increasing in number and expanding their range in Scotland. Aims During the summers of 2008 and 2009, extensive surveys of Greylag Geese in Scotland were undertaken to update the current distribution and population estimates, as well as estimate breeding success. Methods Checks of known moult-sites were combined with a random stratified sample of lochs to the south and east of the Great Glen (the ‘re-established population’ area). Sample lochs were selected on the basis of altitude, the proportional areas of woodland and water cover and previous summer records of Greylag Geese within the 10-km squares in which the lochs were located. To the north and west of the Great Glen (the ‘northwest Scotland’ population area), comprehensive post-breeding counts of feeding areas were undertaken in late August. Results Combined results from 2008 and 2009 suggest an estimated 47 405 (range 44 059–51 763) Greylag Geese in Scotland. Since 1989, Greylag Geese encountered to the south and east of the Great Glen (derived from re-established birds) have increased at an annual rate of about 9.7% per annum and, since 1997, those in northwest Scotland have increased at an annual rate of about 11.7% per annum. It is estimated that the total number of Greylag Geese summering in Britain is about 84 500 birds. In 2008, overall breeding success was 24.1% young in the late summer population, which probably more than compensates for natural and shooting mortality. Conclusion There is no indication of a decline in the rate of increase of Greylag Geese in Scotland and the species is expected to continue to increase in abundance and distribution.