Skip to main content

Research Repository

Advanced Search

Factors affecting bait uptake by the grey squirrel (Sciurus carolinensis) and the future delivery of oral contraceptives

Beatham, S.E.; Coats, J.; Stephens, P.A.; Massei, G.

Factors affecting bait uptake by the grey squirrel (Sciurus carolinensis) and the future delivery of oral contraceptives Thumbnail


Authors

S.E. Beatham

J. Coats

G. Massei



Abstract

Context: Invasive species negatively affect natural communities and human activities. The grey squirrel is an invasive species in the UK, causing damage to forestry and the decline of the native red squirrel. Oral contraceptives have the potential to reduce numbers of grey squirrels; however, to be effective a sufficient proportion of a population must consume a bait containing contraceptives. Aims: The objective of this study was to estimate the efficacy of delivering baits via feeders to grey squirrels and to determine the factors most important to bait uptake. Methods: Bait uptake was measured using the bait marker Rhodamine B mixed with 100% hazelnut butter and delivered to grey squirrels via purpose-designed feeders. Different concentrations of Rhodamine B were first trialled on captive grey squirrels for their palatability and detectability in the hair. Bait-uptake field trials were then conducted in 10 UK woodlands by using the preferred concentration. Key results: In captive trials, it was found that a concentration of 0.18% Rhodamine B mixed in hazelnut butter was palatable to grey squirrels and that individuals needed to consume only small amounts (<5 g) for it to be detected in the flank hair by using an ultraviolet microscope. It was possible to deliver bait to the majority of grey squirrels in 6 of 10 woods within 4 days. Season, feeder density and squirrel density were important factors affecting bait uptake, with more squirrels consuming bait in summer than in winter and from three feeders per hectare rather than from one per hectare. Conclusions: This study demonstrated that baits delivered via feeders can target the majority of grey squirrels in woodland environments. Implications: Oral contraceptives could offer a cost-effective tool to reduce numbers of grey squirrels across the UK landscape and mitigate the negative impacts they have on native wildlife and tree health.

Citation

Beatham, S., Coats, J., Stephens, P., & Massei, G. (online). Factors affecting bait uptake by the grey squirrel (Sciurus carolinensis) and the future delivery of oral contraceptives. Wildlife Research, 51, https://doi.org/10.1071/wr22159

Journal Article Type Article
Acceptance Date Mar 24, 2023
Online Publication Date Apr 13, 2023
Deposit Date Apr 3, 2023
Publicly Available Date Jun 22, 2023
Journal Wildlife Research
Print ISSN 1035-3712
Electronic ISSN 1448-5494
Publisher CSIRO Publishing
Peer Reviewed Peer Reviewed
Volume 51
DOI https://doi.org/10.1071/wr22159
Public URL https://durham-repository.worktribe.com/output/1175478

Files

Published Journal Article (2.4 Mb)
PDF

Publisher Licence URL
http://creativecommons.org/licenses/by-nc-nd/4.0/

Copyright Statement
© 2023 The Author(s) (or their employer(s)). Published by CSIRO Publishing. This is an open access article distributed under the Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License (CC BY-NC-ND)






You might also like



Downloadable Citations