Assessment of the invasion process of the common raccoon Procyon lotor (Carnivora: Procyonidae) on a Mediterranean island a decade after its introduction

[Display omitted] •A well-structured population and a highly reproductive potential points to an increasing population.•Diet analysis shows a highly plasticity trophic ecology which reinforce its population expansion. The common raccoon, Procyon lotor was introduced at the Balearic Islands (Spain) in 2006. Since then, a colonization process has been carried out, with captures of specimens in 24.30% of the surface of the whole Mallorca Island. For the first time, information has been provided on the invasive process of P. lotor in an insular ecosystem. 257 specimens of P. lotor were captured during the period 2007–2018, of them 104 were analysed to estimate population parameters. Demographic data showed that the population had a sex ratio of 1.00:1.21 (males:females), high BMI values and up to 40% of females were lactating when captured. Related to diet data, the composition was mainly the same as previous studies around its natural and introduced distribution area. Plant residues represented the 53.25 ± 38.66% followed by invertebrates with 12.22 ± 22.54%, inorganic remains with 11.9 ± 22.07% and finally the vertebrates with 4.94 ± 18.27%. Thus, it is shown how an opportunistic omnivorous species has adapted to the resources provided by the island. Cultivated plants' remains and plastic content in diet evidence that P. lotor is entering in contact with human settlements and agricultural areas. As occurred in other islands where P. lotor was introduced, it is expected that it could become a future problem for the conservation biodiversity in insular ecosystems, as well as for agriculture and human activity. Due to the potential impact on native biodiversity it is necessary to reinforce the implementation of control actions and prevent its expansion to the rest of the island.