A PIT‐tag–based method for measuring individual bait uptake in small mammals

Abstract Rodents and other small mammals cause an increasing number of negative economic and environmental impacts worldwide. In the UK, the non‐native grey squirrel has a significant impact on the forestry industry and has caused the decline of the native red squirrel. Baits are used to deliver bio...

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Main Authors: Sarah E. Beatham, Dominic Goodwin, Julia Coats, Philip A. Stephens, Giovanna Massei
Format: Article
Language:English
Published: Wiley 2021-04-01
Series:Ecological Solutions and Evidence
Subjects:
Online Access:https://doi.org/10.1002/2688-8319.12081
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author Sarah E. Beatham
Dominic Goodwin
Julia Coats
Philip A. Stephens
Giovanna Massei
author_facet Sarah E. Beatham
Dominic Goodwin
Julia Coats
Philip A. Stephens
Giovanna Massei
author_sort Sarah E. Beatham
collection DOAJ
description Abstract Rodents and other small mammals cause an increasing number of negative economic and environmental impacts worldwide. In the UK, the non‐native grey squirrel has a significant impact on the forestry industry and has caused the decline of the native red squirrel. Baits are used to deliver biocides and contraceptives to reduce overabundant wildlife populations and as vehicles for vaccines to control disease outbreaks. Bait‐delivered contraceptives are also being developed to manage grey squirrel populations in the UK. The effectiveness of bait‐delivered drugs on wildlife populations depends on the amount of bait consumed by individuals over time; therefore, it is important to understand individual level bait uptake in order to optimize delivery methods. Passive integrated transponder (PIT) tags are increasingly used to mark and monitor animal behaviour as they are cost‐effective, have minimal negative welfare impacts and have a lower tag loss rate than external tags, particularly in small animals. The aim of this study was to design and test a novel bait hopper equipped with a PIT‐tag reader and bait‐weighing device, to record bait uptake by individual grey squirrels for optimizing the delivery of a contraceptive bait. The hopper was designed to overcome some of the limitations of traditional PIT‐tag systems, by improving battery life and the quality and quantity of data collected in the field. In captive trials, the hopper proved to be highly effective at recording feeding visits by squirrels, as 95% of the visits could be attributed to a PIT‐tag record. The hoppers measured the amount of bait removed per feeding visit to an accuracy of 0.1 g, with 97% of the bait taken from six hoppers attributed to a PIT‐tag ID. In a field trial, the hoppers were effective at recording the feeding visits by grey squirrels in two woods, with 47 of the 51 PIT‐tagged grey squirrels entering the hoppers. The adaptability of the hopper design means that it has wider applications for wildlife management; in particular, efficacy studies for bait‐delivered substances in the context of wildlife disease control and/or population reduction.
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spelling doaj.art-67fab98fe0b14f5bac016dd90133bdae2022-12-21T20:45:05ZengWileyEcological Solutions and Evidence2688-83192021-04-0122n/an/a10.1002/2688-8319.12081A PIT‐tag–based method for measuring individual bait uptake in small mammalsSarah E. Beatham0Dominic Goodwin1Julia Coats2Philip A. Stephens3Giovanna Massei4National Wildlife Management Centre, APHA Sand Hutton York UKBiomotors Ltd. The Old Rectory, Boughton Malherbe Maidstone Kent UKNational Wildlife Management Centre, APHA Sand Hutton York UKConservation Ecology Group Department of Biosciences Durham University Durham UKNational Wildlife Management Centre, APHA Sand Hutton York UKAbstract Rodents and other small mammals cause an increasing number of negative economic and environmental impacts worldwide. In the UK, the non‐native grey squirrel has a significant impact on the forestry industry and has caused the decline of the native red squirrel. Baits are used to deliver biocides and contraceptives to reduce overabundant wildlife populations and as vehicles for vaccines to control disease outbreaks. Bait‐delivered contraceptives are also being developed to manage grey squirrel populations in the UK. The effectiveness of bait‐delivered drugs on wildlife populations depends on the amount of bait consumed by individuals over time; therefore, it is important to understand individual level bait uptake in order to optimize delivery methods. Passive integrated transponder (PIT) tags are increasingly used to mark and monitor animal behaviour as they are cost‐effective, have minimal negative welfare impacts and have a lower tag loss rate than external tags, particularly in small animals. The aim of this study was to design and test a novel bait hopper equipped with a PIT‐tag reader and bait‐weighing device, to record bait uptake by individual grey squirrels for optimizing the delivery of a contraceptive bait. The hopper was designed to overcome some of the limitations of traditional PIT‐tag systems, by improving battery life and the quality and quantity of data collected in the field. In captive trials, the hopper proved to be highly effective at recording feeding visits by squirrels, as 95% of the visits could be attributed to a PIT‐tag record. The hoppers measured the amount of bait removed per feeding visit to an accuracy of 0.1 g, with 97% of the bait taken from six hoppers attributed to a PIT‐tag ID. In a field trial, the hoppers were effective at recording the feeding visits by grey squirrels in two woods, with 47 of the 51 PIT‐tagged grey squirrels entering the hoppers. The adaptability of the hopper design means that it has wider applications for wildlife management; in particular, efficacy studies for bait‐delivered substances in the context of wildlife disease control and/or population reduction.https://doi.org/10.1002/2688-8319.12081biocidescontraceptivesfeeding behaviourgrey squirrelmicrochipremote sensing
spellingShingle Sarah E. Beatham
Dominic Goodwin
Julia Coats
Philip A. Stephens
Giovanna Massei
A PIT‐tag–based method for measuring individual bait uptake in small mammals
Ecological Solutions and Evidence
biocides
contraceptives
feeding behaviour
grey squirrel
microchip
remote sensing
title A PIT‐tag–based method for measuring individual bait uptake in small mammals
title_full A PIT‐tag–based method for measuring individual bait uptake in small mammals
title_fullStr A PIT‐tag–based method for measuring individual bait uptake in small mammals
title_full_unstemmed A PIT‐tag–based method for measuring individual bait uptake in small mammals
title_short A PIT‐tag–based method for measuring individual bait uptake in small mammals
title_sort pit tag based method for measuring individual bait uptake in small mammals
topic biocides
contraceptives
feeding behaviour
grey squirrel
microchip
remote sensing
url https://doi.org/10.1002/2688-8319.12081
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