An (Un)Expected Threat for a Regionally Near-Threatened Species: A Predation Case of a Persian Squirrel on an Insular Ecosystem

SIMPLE SUMMARY: Among introduced alien species, one of the most widespread and successful predators on island ecosystems is the domestic cat. This opportunistic carnivore is considered responsible for numerous island species’ extinctions and species’ population declines, with small mammals having the higher predation risk among all species that are preyed upon. In this work, we present the first evidence, from the island of Lesvos, of a feral cat hunting, killing, and consuming a full-grown Persian squirrel. In the locality of the event, we further examined both squirrels’ and cats’ population densities based on these species’ home ranges. Results showed that the population of feral cats is almost fifteen times higher than that of squirrels, which raises concerns regarding the species’ conservation. Our observation reinforces the need for feral cat management to be prioritized for the conservation of this native and regionally near-threatened species. ABSTRACT: One of the most successful predators on island ecosystems is the domestic cat, which is considered responsible for the decline of numerous species’ populations. This can be estimated by the analysis of cats’ dietary habits, yet prey identification is not always possible, and thus, in cases where precise prey identification is required, one of the most accurate methods derives from observing the hunting process. However, the cryptic nature of the feral cats and the constant vigilance of the species that are preyed upon make the observation process difficult, especially when the prey has a low population density. Here, we report for the first time such a case: a feral cat that has ambushed, killed, and consumed a regionally near-threatened species, the Persian squirrel. This incidental observation happened in the squirrel’s westernmost end of its distribution, the island of Lesvos, Greece. Due to the unexpectedness of the event, in the following days, we estimated both the squirrels’ and cats’ population density. Results showed that while the density of the squirrels is moderate, the population density of the feral cats is almost fifteen times higher. For this reason, management actions need to be taken in an effort to minimize the impacts of feral cats on the native species of the island.