There is widespread concern about the negative impacts of plastic and other anthropogenic solid waste (hereafter referred to as ‘plastics’) on global biodiversity (Law, 2017; Lau et al., 2020). Such materials are extremely slow to break down, which has resulted in discarded micro- and macroplastics accumulating in marine and terrestrial ecosystems (Thompson et al., 2009; Wang et al., 2021). Plastics are prevalent in environments heavily modified by humans, including urban areas and farmland (Reynolds et al., 2019; MacLeod et al., 2021).
One way in which plastics discarded in the environment negatively impact animal reproduction occurs when they are nest constituents. Nests are built by a range of vertebrate and invertebrate taxa, including fishes, reptiles, insects, amphibians, birds and mammals (Mainwaring et al., 2014). These structures determine the conditions in which their offspring develop and, therefore, are fundamental to breeding outcomes. Although plastics have been incorporated into the nests of mammals (Deeming, 2023) and turtles (Khalid et al., 2025), they appear to be increasingly prevalent in birds’ nests in the form of cigarette butts, plastic bag fragments, baler twine etc. (Potvin et al., 2021; Jagiello et al., 2023).
Plastic inclusion in nests is evidently disadvantageous through, for example, nestling entanglement preventing them from fledging (e.g. Townsend and Barker, 2014), and higher predation of eggs and nestlings with increased plastic load (e.g. Møller, 2017). Therefore, we urgently need to understand the presence of such materials in birds’ nests and its consequences for bird populations.
Here, we will investigate plastic use in established breeding populations of open-nesting Common Blackbirds (Turdus merula), and closed-nesting Blue (Cyanistes caeruleus) and Great Tits (Parus major) across an urbanisation gradient in Birmingham, and on agricultural land and in woodland close to Bangor, North Wales. We will [1] quantify presence and abundance of plastic in the nests across habitat types, and [2] investigate plastic preference by nest-building birds in nest material choice field experiments and the consequences for co-pollutant exposure. Finally, [3] we will examine plastic use by nesting birds globally using image archives such as YouTube, Google Images etc. and relate it to land-use (e.g. urbanisation), pollution etc.
Figure 1: An active nest of a pair of Upland Buzzards (Buteo hemilasius) near Qumahexiang, Yushu, Qinghai, China containing a large number of agricultural solid waste materials. (Photo reproduced by kind permission of Steb Fisher).
This project is not suitable for CASE funding
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This project focuses on open-nesting Common Blackbirds and closed-nesting Blue Tits and Great Tits in Bangor and Birmingham, UK. We will test the research hypotheses using nestboxes for tits that have been monitored for a number of years in both urban and rural environments. This will allow nest contents (including plastics) and breeding outcomes to be related to land-use as likely sources of nest materials and associated contaminants in each nest. Similar relationships will be established for nesting blackbirds, the breeding outcomes of which will be made available as part of two other ongoing CENTA-funded PhD student projects.
After nest collection at the end of each breeding season in Bangor and Birmingham, plastic will be characterised through gross nest dissection before further analyses to examine materials and their associated contaminants (via leaching experiments) in finer detail in state-of-the-art laboratories in the Molecular Sciences Building on the Birmingham University campus.
DRs will be awarded CENTA Training Credits (CTCs) for participation in CENTA-provided and ‘free choice’ external training. One CTC can be earned per 3 hours training, and DRs must accrue 100 CTCs across the three and a half years of their PhD.
Training will be offered in each of the above research areas within the host institutions. It will comprise postgraduate training and external training, including using R for the analysis of complex spatial environmental datasets, and Geographic Information Systems (GIS) and remote sensing data (via Google Earth Engine) to capture and depict variability of land-use in Bangor and Birmingham. The candidate will also be trained in nest monitoring and deconstruction, and in using a sophisticated suite of laboratory-based methodologies to analyse the physical and chemical properties of anthropogenic nest materials (plastics and associated chemicals).
Not applicable.
Year 1: Project development and DR training (e.g. statistics, nest finding and observation, experimental design). Data capture using remote sensing datasets (e.g. Google Earth Engine) to characterise land-use in nesting territories, familiarity with field sites in Bangor and Birmingham, nest monitoring and deconstruction etc.
Year 2: Paper writing. Fieldwork at Bangor and Birmingham field sites, including nest finding in blackbirds and nest collection from nestboxes. Deconstruction and analysis of nests in the laboratory, including microscopic identification, micro-FTIR analysis and suspect screening for plastic additives. Conference attendance (national).
Year 3: Ongoing fieldwork and laboratory work, data analysis, modelling, and paper- and thesis-writing. Conference attendance (international).
Deeming, D. C. 2023. Nest construction in mammals: A review of the patterns of construction and functional roles. Philosophical Transactions of the Royal Society B: Biological Sciences 378: 20220138. https://doi/10.1098/rstb.2022.0138.
Jagiello, Z., Reynolds, S. J., Nagy, J., Mainwaring, M. C. and Ibáñez-Álamo, J. D. 2023. Why do some bird species incorporate more anthropogenic materials into their nests than others? Philosophical Transactions of the Royal Society B: Biological Sciences 378: 20220156. https://doi.org/10.1098/rstb.2022.0156.
Khalid, A. A., Razak, N. I. A., Anuar, S. T., Ibrahim, Y. S., Rusli, M. U. and Jaafar, M. 2025. Microplastics contamination in natural sea turtle nests at Redang Island, Malaysia. Marine Pollution Bulletin 211: 117412. https://doi.org/10.1016/j.marpolbul.2024.117412.
Lau, W. W. Y. et al. 2020. Evaluating scenarios toward zero plastic pollution. Science 369: 1455–1461. https://doi/10.1126/science.aba9475.
Law, K. L. 2017. Plastics in the marine environment. Annual Review of Marine Science 9: 205–217. https://doi.org/10.1146/annurev-marine-010816-060409.
MacLeod, M., Arp, H. P. H., Tekman, M. B. and Jahnke, A. 2021. The global threat from plastic pollution. Science 373: 61–65. https://doi/10.1126/science.abg5433.
Mainwaring, M. C., Hartley, I. R., Lambrechts, M. M. and Deeming, D. C. 2014. The design and function of birds’ nests. Ecology and Evolution 4: 3909–3928. https://doi/10.1002/ece3.1054.
Møller, A. P. 2017. Fashion and out of fashion: Appearance and disappearance of a novel nest building innovation. Avian Research 8: 14. https://doi.org/10.1186/s40657-017-0072-7.
Potvin, D. A., Opitz, F., Townsend, K. A. and Knutie, S. A. 2021. Use of anthropogenic-related nest material and nest parasite prevalence have increased over the past two centuries in Australian birds. Oecologia 196: 1207–1217. https://doi.org/10.1007/s00442-021-04982-z
Reynolds, S. J., Ibáñez-Álamo, J. D., Sumasgutner, P. and Mainwaring, M. C. 2019. Urbanisation and nest building in birds: A review of threats and opportunities. Journal of Ornithology 160: 841–860. https://doi.org/10.1007/s10336-019-01657-8.
Thompson, R. C., Moore, C. J., vom Saal, F. S. and Swan, S. H. 2009. Plastics, the environment and human health: Current consensus and future trends. Philosophical Transactions of the Royal Society B: Biological Sciences 364: 2153–2166. https://doi.org/10.1098/rstb.2009.0053.
Townsend, A. K. and Barker, C. M. 2014. Plastic and the nest entanglement of urban and agricultural crows. PLoS ONE 9(1): e88006. https://doi.org/10.1371/journal.pone.0088006.
Wang, L., Nabi, G., Yin, L., Wang, Y., Li, S., Hao, Z. and Li, D. 2021. Birds and plastic pollution: Recent advances. Avian Research 12: 59. https://doi.org/10.1186/s40657-021-00293-2.
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Applications must be submitted by 23:59 GMT on Wednesday 7th January 2026.