Grant, Megan LO'Hanlon, Nina JLavers, Jennifer LMasden, Elizabeth AJames, Neil ABond, AL2022-11-252022-11-252021-11Megan L. Grant, Nina J. O'Hanlon, Jennifer L. Lavers, Elizabeth A. Masden, Neil A. James, Alexander L. Bond, A standardised method for estimating the level of visible debris in bird nests, Marine Pollution Bulletin, Volume 172, 2021, 112889, ISSN 0025-326X, https://doi.org/10.1016/j.marpolbul.2021.112889.0025-326X10.1016/j.marpolbul.2021.112889http://hdl.handle.net/10141/623031Unlike records of plastic ingestion and entanglement in seabirds which date back to the 1960s, the literature regarding debris in bird nests is comparatively limited. It is important to identify standardised methods early so that data are collected in a consistent manner, ensuring that future studies can be comparable. Here, we outline a method that can be applied to photographs for estimating the proportion of visible debris at the surface of a nest. This method uses ImageJ software to superimpose a grid onto a photograph of a nest/s. The number of cells with and without debris are then counted. Our proposed method is repeatable, straightforward, and accessible. We optimised the method to estimate the level of visible debris in Northern Gannet (Morus bassanus) nests, however, with some modification (i.e., adjustment of grid cell size), it could be applied to other seabird species, and terrestrial birds, that incorporate debris within nests.enopenAccesshttps://creativecommons.org/licenses/by/4.0/Journal Article1879-3363Marine Pollution Bulletin2022-11-24172112889-112889community scienceenvironmental indicatorimage analysisplastic pollutionpolicyseabirds