The Plastic Free Menorca Alliance has received a grant from the Ministry of Agriculture, Fisheries and the Natural Environment of the Government of the Balearic Islands to promote the implementation of the "Plastic Observatory", an initiative that aims to reduce the use of plastics through the objective analysis of their management, their impacts and regulations, as well as the subsequent dissemination of the results to society.
The first indicator analyzes for the first time the presence of plastic waste in the nests of the yellow-legged gull (Larus michahellis) on the Illa de l'Aire.
For the data collection, we have had the collaboration of the Societat Ornitològica de Menorca (SOM), which during its ringing campaign in April of this year observed and voluntarily collected all the field data necessary for the study.
In total, 77 nests have been analysed between 21 and 27 April 2025. The field data recorded include five types of information: the diameter of the nest, the existence of eggs and/or chicks, the presence of waste – differentiating between filaments, rubber/polystyrene, hard plastics, laminar plastics and others – and the color of each waste identified.
The results, analysed by the Plastic Free Menorca Alliance with the collaboration of Raül Escandell, from the Societat Ornitològica de Menorca, reveal that 8 out of 10 nests (82%) contain waste, mostly plastic materials. Laminar plastics are the most common type (47%), followed by plastic filaments (28.7%) and rubber/porexpan (9.6%). Fragments of aluminum foil, paper, hard plastics and textile remains have also been identified. The predominant colour is white (62.9%), mainly associated with pieces of bags and other laminar plastics.
"It is essential to start having real and objective data that shows the local impact of plastic pollution. Only in this way will we be able to guide the correct actions to combat pollution that, continuously and increasingly, is affecting the nature of the island and also the people who live on it," says Marta Pérez, coordinator of the Plastic Free Menorca Alliance. And he adds that "the impact of plastics goes far beyond the landscape: it is altering ecosystems and directly affecting the biodiversity of Menorca. The seagulls tell us that pollution is present even in apparently remote areas such as the Illa de l'Aire."
Comparison of these data with the Canary Islands
The report incorporates a comparison with a study carried out in biosphere reserves of the Canary Islands (2020–2021), carried out in abandoned nests in Lanzarote and Fuerteventura. On these islands, likewise, 8 out of 10 nests contained waste, although the composition pointed to a terrestrial origin, more related to immediate consumption, such as food packaging and personal hygiene products.
On the other hand, in Menorca – where the study has been carried out on the Illa de l'Aire, an islet separate from the main island – the almost total predominance of plastics (87% of the items identified) suggests more diffuse sources, possibly linked to marine pollution, fishing gear or debris generated by coastal activities.
A serious risk to island fauna
The presence of plastics in nests can cause tangles, accidental ingestion, hinder the correct construction of the nest or interfere with the development of chicks.
Regarding the possibility of using this data to determine if seagulls can also ingest plastics, Raül Escandell explains that "seagulls are selective animals in terms of food and do not usually collect waste if they do not retain the smell of food. Even so, in order to have more rigorous data, it would be interesting to analyse the presence of plastics in pellets in future campaigns. Some bird species expel indigestible parts (feathers, hair, bones, nails and teeth) through their mouths in the form of compact balls called pellets, which can provide key information on this aspect."
Call to action
The Plastic Free Menorca Alliance warns that these data constitute a an unequivocal sign of the need to intensify prevention and reduction of waste, especially in sensitive natural environments.
Continuous monitoring will make it possible to analyse the evolution of the problem and guide more effective public policies and environmental initiatives to move towards an increasingly plastic-free.
