AbstractStable isotope analyses of museum specimens provide an opportunity to examine long-term changes in avian migration strategies. Here, we determined stable isotopes of carbon (δ13C) and nitrogen (δ15N) in body feathers (reflecting diet during the non-breeding period) sampled from living birds and historical museum specimens to investigate whether brown skuas Stercorarius antarcticus lonnbergi from South Georgia and the South Shetland Islands changed their migration strategies during the past 100 years. Feathers sampled from adults in the 2010s at South Georgia had significantly lower δ13C and δ15N values than feathers from the 1910s, potentially indicating a shift from oceanic subtropical and continental shelf-slope waters towards mixed subtropical–subantarctic to subantarctic waters in the Argentine Basin. No isotope values (modern nor historical) from South Georgia were consistent with wintering on the Patagonian Shelf (rather than the shelf-slope). Feathers sampled at the South Shetland Islands in the 2020s had significantly lower δ13C and δ15N values than specimens collected 60–100 years previously. A plausible explanation here is reduced reliance on continental shelves and increased use of mixed subtropical–subantarctic to subantarctic waters as wintering destinations over time. Overall, our study highlights how museum collections can be used to investigate changing migration strategies of marine predators, including in remote oceanic ecosystems.

Microplastics have emerged as pervasive environmental contaminants, raising concerns over their impacts on wildlife. Birds of prey occupy high trophic positions and hence are particularly vulnerable to accumulating high contaminant levels due to potential biomagnification. We used regurgitated pellets as a non-invasive proxy for dietary microplastic exposure in two apex predators that share overlapping habitats in the United Kingdom (UK): barn owls (Tyto alba) and common kestrels (Falco tinnunculus). We collected regurgitated pellets (n = 24 per species), which were chemically digested and microplastics were enumerated and identified using Fourier-transform infrared spectroscopy (FTIR), and sorted into five size classes ranging from 25 to 200+ μm. Overall, 92% of kestrel pellets and 83% of barn owl pellets contained microplastics. Kestrel pellets had 18.46 microplastic particles g-1, which was significantly higher than in barn owl pellets, which had 0.42 particles g-1 (p = 0.03). Of a possible 20 polymers, 13 were detected with significant variations in occurrence between the two species. Overall, the dominant polymers were polypropylene (8.2%), polyurethane (9.2%), polyethylene (36.8%), ethylene vinyl alcohol (3.1%) and ethylene vinyl acetate (37.3%). Additionally, there were significant differences in number of microplastic particles between repeat sampling of the same nests. The largest number of particles were found in the 25-50 μm range, with 25 μm being the detection limit of our FTIR instrument. These findings demonstrate species-specific microplastic exposure, which may be driven by the variable microplastic load of different prey. To our knowledge, this study is the first to investigate microplastic ingestion by birds of prey in the UK.

The mechanical properties of dietary items are known to influence skull morphology, either through evolution or by phenotypic plasticity. Here, we investigated the impact of supplementary feeding of peanuts on the morphology of red squirrels ( Sciurus vulgaris ) from five populations in Britain (North Scotland, Borders, Jersey and two temporally distinct populations from Formby (Merseyside)). Stable isotope analysis confirmed dietary ecology in 58 specimens. Geometric morphometrics were used to analyse three-dimensional and two-dimensional shape variation across 113 crania and 388 mandibles, respectively. Nitrogen isotope ratios (δ 15 N) were lower in the 1990s and 2010s Formby squirrels (suggesting a diet with an increased proportion of peanuts), and higher in other populations. Significant differences in cranio-mandibular shape were found between all populations, with 1990s Formby red squirrels exhibiting a morphology associated with reduced masticatory efficiency. This effect was partially reversed following a reduction in supplementary feeding of peanuts. We propose that these morphological changes are related to the reduced mechanical effort needed to process peanuts relative to naturally occurring food items. This could be an example of diet-induced plastic changes to the skeleton in non-muroid wild mammals, although further research is needed to exclude other driving factors such as genetics.

Ticks are obligate haematophagous ('blood-sucking') ectoparasites that are capable of retaining host dietary traces post-moult, providing an opportunity to investigate parasite-host interactions and explore their potential as non-invasive subsampling techniques. However, research on the preservation of biochemical host signatures within whole engorged parasites remains limited. Here, we examine stable isotope ratios of nitrogen (δ15N) and carbon (δ13C) across different tick tissues (exoskeleton vs. blood meal) and between whole ticks and one of their hosts, the European polecat Mustela putorius. Additionally, carbon and nitrogen weight percentages (wt%) are assessed to explore potential biochemical changes linked to blood meal digestion. Our findings showed that the isotopic composition of tick exoskeleton and blood meal differed significantly, with exoskeletons potentially reflecting a previous host. Whole engorged ticks showed a close δ15N relationship to their host, consistent with that of trophic enrichment, while the observed δ13C values were more variable. These findings enhance our understanding of how haematophagous parasites preserve host dietary signatures and, with further research, could support their use as a valuable alternative to invasive sampling methods, particularly when destructive sampling is not feasible.

Birds of prey ('raptors') often consume anthropogenic foods and can be closely associated with human settlements. In medieval Britain, birds of prey were commensal animals, especially in towns where biological waste was abundant. However, the antiquity of this relationship has not been well explored. In this study, we used stable isotopes of carbon (613C) and nitrogen (615N) in bone collagen to investigate the dietary niches of red kites Milvus milvus, common buzzards Buteo buteo and white-tailed eagles Haliaeetus albicilla of Chalcolithic or Early Bronze Age, Iron Age, Roman and medieval periods from archaeological sites across southern and midland England and in Orkney (Scotland). Stable isotope values of raptor bones recovered from Iron Age Danebury, Roman Winchester, and medieval Oxford were consistent with the exploitation of livestock waste from food produced for human inhabitants. Combining all samples, bone collagen 613C values were significantly less negative and 615N values significantly higher in red kites and common buzzards from archaeological sites across Iron Age, Roman and medieval England than those of modern birds (dating from the late 20th and 21st centuries), and both species showed greater variability among individuals. The diets of historic birds may include prey from higher trophic levels and reflect a more generalist strategy. These data are consistent with the consumption of larger quantities of anthropogenic food waste including carrion from scavengers and slaughtered and farmed livestock animals, which is reduced in volume in today's landscapes. Archaeological raptors may also have exploited a wider range of scavenged or hunted prey in the absence of rabbits Oryctolagus cuniculus, a key prey item for modern-day raptors.

Climate change is expected to expand the geographic ranges of ectoparasites, increasing the transmission of vector-borne diseases and necessitating a better understanding of ectoparasite-host trophic dynamics. Haematophagous ectoparasites can serve as valuable subsamples of their hosts, retaining isotopic values that reflect dietary information in both their blood meals and tissues. However, differences in the life histories and feeding strategies of lice, fleas and ticks may influence how host isotopic composition is preserved. Here, stable isotope values of carbon (δ13C) and nitrogen (δ15N) were used to investigate trophic interactions between ectoparasites and their mammalian hosts in three pairings: lice (Anoplura: Polyplacidae; n = 101) from Eurasian red squirrels Sciurus vulgaris L. (Rodentia: Sciuridae), fleas (Siphonaptera: Ceratophyllidae; n = 92) from fat dormice Glis glis L. (Rodentia: Gliridae) and ticks (Ixodida: Ixodidae; n = 16) from European hedgehogs Erinaceus europaeus L. (Eulipotyphla: Erinaceidae). Our findings indicate that ectoparasites reflect the dietary patterns of their hosts, with lice exhibiting the closest isotopic values, followed by fleas and ticks. All parasites had significantly higher δ15N values than their hosts, indicative of trophic enrichment, but their δ13C values varied. Notably, we found that the presence of a blood meal did not significantly affect the isotopic values found in lice and fleas, while ticks showed a significant difference between exoskeleton and blood meal in δ13C values. This study highlights the importance of understanding how the life histories of parasite species influence the preservation of isotopic host signals in order to be able to utilise stable isotope analyses of ectoparasites to infer host dietary niches and preferences, with broader implications for understanding host-parasite dynamics and disease transmission pathways.

Species reintroductions are increasingly seen as important methods of biodiversity restoration. Reintroductions of red kites Milvus milvus and white-tailed eagles Halieaeetus albicilla to Britain, which were extirpated in the late 19th and early 20th centuries, represent major conservation successes. Here, we measured stable isotope ratios of carbon (δ13C) and nitrogen (δ15N) in feather keratin and bone collagen of museum specimens of red kites and white-tailed eagles, which were collected from across Scotland between the 1800s and 2010s. Our objectives were to investigate dietary differences between species and between the pre- and post- reintroduction periods. Among reintroduced birds, δ13C values were significantly less negative and δ15N values higher in feather keratin and bone collagen of white-tailed eagles compared to red kites, likely reflecting a greater reliance on marine resources by the former. Our stable isotope data showed a wide range, confirming the dietary diversity observed in conventional diet studies of both taxa, with white-tailed eagles, in particular, having wide dietary niches and a considerable degree of inter-individual variability. Isotopic data from pre-introduction red kites mostly fell within the range of post-reintroduction birds, suggesting they had similar diets to the pre-reintroduction birds, or the prey base for modern birds is isotopically indistinguishable from that of their historic counterparts. For white-tailed eagles, several pre-reintroduction birds were isotopically distinct from the post-reintroduction population. These differences may indicate a changing prey base, although these conclusions are complicated by shifting distributions and small population samples. Overall, our study demonstrates the utility of natural history collections in examining changes in diet, environment, and interactions with humans in reintroduced species compared with pre-extirpation indigenous populations.

Antarctic marine ecosystems are located far from industrial pollution sources, yet mercury (Hg) contamination remains an important threat to regional biodiversity. Seabirds occupy mid- to high trophic positions in Antarctic food webs, and can show high levels of Hg contamination due to biomagnification. Here, total Hg (THg) concentrations and stable isotopes of carbon (δ13C) and nitrogen (δ15N) were measured in red blood cells of brown skuas Stercorarius antarcticus lonnbergi (n = 44) and south polar skuas S. maccormicki (n = 50) at King George Island/Isla 25 de Mayo (South Shetland Islands) in the 2022/23 and 2023/24 breeding seasons. The objectives were to: (i) determine current levels of Hg contamination at King George Island and identify the underlying drivers (e.g., species, sex, year, δ13C and δ15N); (ii) compare contaminant levels with other breeding sites; and (iii) examine potential Hg-associated health risks. At King George Island, south polar skuas had higher THg concentrations (mean ± SD, 3.85 ± 2.99 μg g-1 dw) than brown skuas (1.67 ± 1.25 μg g-1 dw), potentially due to their greater reliance on mesopelagic fish and carry-over effects from their non-breeding distributions. THg concentrations of males were higher than females, with deposition into eggs by females being the likeliest explanatory factor, and were positively related to δ15N, reflecting the biomagnification process. THg concentrations of brown skuas in this study were higher than at Hope Bay (Antarctic Peninsula), but lower than at South Orkney Islands (Antarctica), South Georgia and Kerguelen Islands (subantarctic). THg concentrations of the south polar skuas analysed here were higher than at Hope Bay and Adélie Land (Antarctic continent). Comparisons with toxicity benchmarks suggest that skuas are currently at low risk of Hg-associated health impacts at King George Island.

The role of zoos has shifted markedly from their origins in the nineteenth century to the present day. Long-lived and charismatic individual animals have been central to zoological collections, as priorities have changed from a primary focus on entertainment to a greater emphasis on education, conservation, research and welfare. Here, we construct the osteobiography of a celebrity chimpanzee to highlight the changing practices of modern zoos over a near half-century timescale. We applied archival, biogeochemical, pathological, and morphometric analyses to the skeleton and tissues of Choppers, a captive female western chimpanzee (Pan troglodytes verus), who featured in the PG Tips television advertisements in the United Kingdom in the 1970s. We show the efficacy of the osteobiographical method in revealing Choppers’ life events, including her capture from the wild, dietary transitions over decadal timescales, and her declining health in old age. These direct analytical techniques applied to her physical remains allow for a more in-depth understanding of her life history than from archival material alone. By using a mixed-method, in-depth assessment of a single captive chimpanzee, we provide a rich context for analysing the impact of the changing roles of zoos on captive animals during the late 20th and 21st centuries.

This study builds on a preliminary investigation into the efficacy of gamma radiation surveying as a complementary tool for archaeological prospection. Improved surveying and data processing methods were implemented, including the use of a vehicle-mounted Groundhog surveying system, use of alternative software tools and examination of the impacts of individual radionuclides. The study focuses on a range of targets within Insulae VII, XXXV and XXXIII in Silchester Roman town, Hampshire. Targets of interest included a polygonal temple, a house, ditches (including an Iron Age defensive ditch) and several Roman roads. While the survey revealed no measurable differences in the gamma radionuclide content of less substantial structures (such as the temple and house) and the surrounding soil, it successfully delineated major structures. The Roman roads, Iron Age defensive ditch and potentially an indication of a historic field boundary not present in modern records were clearly visible in the generated visualisations. The roads and field boundary appear as distinct linear features of depleted radioactivity. The location of the Iron Age ditch correlates with an area of elevated radioactivity. Notably, the technique not only successfully identified archaeological features but was also able to indicate differences in the properties of similar targets such as variations in road thickness. Further, the gamma radiation data indicates variations in the local geology attributable to historic changes in land use and geochemical composition. This latest study corroborates the findings of the preliminary investigation, demonstrating replicability, scalability and ability to enhance output data quality. Further research, including sampling and non-destructive analysis of materials from the site, is needed to better explain observed results.

Procellariiform seabirds can accumulate high levels of plastic in their gastrointestinal tracts, which can cause physical damage and potentially provides a contamination route for trace elements. We examined plastic ingestion and trace element contamination of fledgling Manx shearwaters Puffinus puffinus that were harvested for human consumption in 2003 and 2018 on Skúvoy, Faroe Islands (North Atlantic Ocean). Overall, 88% of fledglings contained plastic in their gastrointestinal tracts, with a mean (± SD) of 7.2 ± 6.6 items weighing 0.007 ± 0.016 g. Though the incidence was similar, fledglings ingested significantly more plastic in 2018 compared to 2003. Hepatic trace element concentrations were unrelated to plastic ingestion. Hepatic carbon (δ13C) and nitrogen (δ15N) stable isotope values were significantly lower in birds sampled in 2018 versus 2003, potentially reflecting further offshore feeding at lower trophic levels. Future research is needed to understand the extent of plastic ingestion by Faroe Islands seabirds.

Supplementary Figure Legends - PDF file 97K, This file contains figure legends for the supplementary figures

Maximal Velocity and Km values

Phytolith analysis is a well-established archaeobotanical tool, having provided important insights into pre-Columbian crop cultivation and domestication across Amazonia through the Holocene. Yet, its use as a palaeoecological tool is in its infancy in Amazonia and its effectiveness for reconstructing pre-Columbian land-use beyond archaeological sites (i.e., ‘off-site’) has so far received little critical attention. This paper examines both new and previously published soil phytolith data from SW Amazonia to assess the robustness of this proxy for reconstructing pre-Columbian land-use. We conducted the study via off-site soil pits radiating 7.5 km beyond a geoglyph in Acre state, Brazil, and 50 km beyond a ring-ditch in northern Bolivia, spanning the expected gradients in historical land-use intensity. We found that the spatio-temporal patterns in palm phytolith data across our soil-pit transects support the hypothesis that pre-Columbian peoples enriched their forests with palms over several millennia, although phytoliths are limited in their ability to capture small-scale crop cultivation and deforestation. Despite these drawbacks, we conclude that off-site soil phytolith analysis can provide novel insights into pre-Columbian land use, provided it is effectively integrated with other land-use (e.g., charcoal) and archaeological data.

HTRF and Biacore binding data for active and inactive ERK1 in the presence of SCH772984

ABSTRACT Uncertainty remains over local‐scale responses of ecotonal Amazonian forests to middle Holocene drying due to the scarcity, and coarse spatial resolution, of lacustrine pollen records. This paper examines the palaeoecological potential of soil phytoliths, stable carbon isotopes and charcoal for capturing local‐scale ecotonal responses of different types of Bolivian Amazonian forest to middle Holocene climate change. Soil pits 1 m deep were dug at ecotones between rainforest, dry forest, Chaco woodland and savannah, and sampled at 5–10 cm resolution. Both phytolith and stable carbon isotope records indicate stability of dry forest–savannah ecotones over the last ca. 6000 years, despite middle Holocene drought, revealing the dominance of edaphic factors over climate in controlling this type of ecotone. In contrast, δ 13 C data reveal that rainforest–savannah ecotones were more responsive to climate change, with rainforest likely replaced by drought‐tolerant dry forest or savannah vegetation during the mid‐Holocene, consistent with regional‐scale lacustrine pollen records. However, such shifts are not apparent in most of our phytolith records due to insufficient taxonomic resolution in differentiating rainforest from dry forest. Charcoal data show that ecotonal dry forests experienced greater fire activity than rainforests and that recent high fire activity at all forest sites is unprecedented since at least the middle Holocene.

Supplementary Figures - PDF file 1385K, File contains Supplementary figures of resistant cell lines, proliferation assay of a panel of cell lines, TdF binding assay transcriptional out and kinome selectivity

Sequencing of HCT116 resistant (HCT116R) cell lines