A standardised method for estimating the level of visible debris in bird nests. (November 2021)

• Record Type: Journal Article
• Authors: Grant, Megan L.; O'Hanlon, Nina J.; Lavers, Jennifer L.; Masden, Elizabeth A.; James, Neil A.; Bond, Alexander L.
• Is Part Of: Marine pollution bulletin. Volume 172(2021)
• Publication Date: 2021-11
• Subjects: Community science -- Environmental indicator -- Image analysis -- Plastic pollution -- Policy -- Seabirds; Marine pollution -- Periodicals; Marine Biology -- Periodicals; Water Pollution -- Periodicals; Mer -- Pollution -- Périodiques; Publications périodiques; Pollution des mers; Lutte antipollution; Electronic journals; 363.7394
• DOI: 10.1016/j.marpolbul.2021.112889
• Languages: English
• ISSNs: 0025-326X

Abstract

Abstract: Unlike 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. Graphical abstract: Unlabelled Image Highlights: New method for estimating the proportion of debris in bird nests from photographs Method is standardised, repeatable, and accessible. Lends itself to community science, as photographs of colonies can be crowd-sourced. Trends in pollution can be assessed if method is used in future nest monitoring.