Knowledge, management and optimization: the use of live traps in control of non-native squirrels

Abstract

This study identifies techniques to maximize trap efficiency and minimize trapping effort when using live traps to capture the invasive alien Pallas’s squirrel (Callosciurus erythraeus), which was introduced in Italy near the Swiss borders. We explored the effects of time of day, season, number of checks in the capture session and type of live trap (single or multi-capture). Moreover, the vegetation around traps (characteristics of the tree supporting the trap, vegetation growth, vegetation cover, vegetation richness and similarity index) was tested. Squirrels were caught more frequently in the morning, but trapping success was not affected by the type of trap used. Squirrel trap response varied significantly in relation to the season, and a higher trapping success in the first days of the trapping session suggests the importance of prebaiting. We reject the hypothesis that vegetation around traps affected the capture success of Pallas’s squirrel in deciduous forests. Thus, recommendations to improve the trapping efficiency of this species are to (1) use single capture live traps with at least one week of prebaiting, (2) increase the capture effort in winter and (3) set traps where access is easy and where there are signs of high activity of individuals of the alien species

Exotic Pet Trade as a Cause of Biological Invasions: The Case of Tree Squirrels of the Genus Callosciurus

“…However, population control programs may be the only true alternative to inaction in the vast majority of cases of Callosciurus invasions [45]. Intensive live trapping with euthanasia, sterilization with release or retention in captivity and shooting are the methods used with maximum success in the eradication of small, localized populations or population control in Belgium, France, Italy, Japan and the Netherlands [62,63,158,160,164]. For any management actions, success is due to a broad-based socioecological approach where human interactions are given consideration [166].…”

“…comm.). A lack of continuous effort directed towards control by trapping and euthanasia, as well as by shooting, has resulted in insufficient results in the control of Pallas's squirrels [158]. Italy has no management plan for C. finlaysonii: the small population at Acqui Terme has never been subject to control, while the Southern Italian population around the town of Maratea has only used lowintensity trapping, with carcasses of the euthanized animals used for a series of veterinary studies [144].…”

Simulating a ‘landscape of fear’: Eastern grey squirrels (Sciurus carolinensis) reduce proportional feeding duration under exposure to native and invasive predator cues

“…Since its introduction to Britain more than 140 years ago, the range of eastern grey squirrels (Sciurus carolinensis) has increased substantially (Gurnell et al 2009). The expansion of grey squirrels is often associated with the decline of the native Eurasian red squirrel (Sciurus vulgaris), through a range of factors including the transmission of squirrel poxvirus (SQPV) (Sainsbury et al 2000;Gurnell et al 2012), superior foraging e ciency (Mazzamuto et al 2016), behavioural dominance (Gurnell et al 2004), and forest cover (Gurnell et al 2014). Currently, grey squirrel management may be achieved through trapping and shooting (BASC 2016).…”

Preventing species invasion: A role for integrative taxonomy?

“…Their capability to establish viable populations from only a few founders has made them successful invaders (Palmer et al 2007;Bertolino 2009;Martinoli et al 2010). Over the past decade a new alien invasive tree squirrel of the genus Callosciurus, native to Southeast Asia, has established a wild population in Northern Italy (Mazzamuto et al 2015) in co-occurrence with the native Eurasian red squirrel, Sciurus vulgaris Linnaeus, 1758. The history of Callosciurus invasions is recent and there is still little information on the impacts of these squirrels at the local scale despite their high invasiveness worldwide .…”