Resources Information Standards Committee Resources Inventory Committee Homepage

Inventory Methods for
Small Mammals:
Shrews, Voles, Mice & Rats

Standards for Components of British Columbia's Biodiversity No. 31

Prepared by
Ministry of Environment, Lands and Parks
Resources Inventory Branch
for the Terrestrial Ecosystems Task Force
Resources Inventory Committee

May 6, 1998
Version 2.0

Back to Task Force Index


This manual presents standard methods for inventory of shrews, mice, voles and rats in British Columbia at three levels of inventory intensity: presence/not detected (possible), relative abundance, and absolute abundance. The manual was compiled by the Elements Working Group of the Terrestrial Ecosystems Task Force, under the auspices of the Resources Inventory Committee (RIC). The objectives of the working group are to develop inventory methods that will lead to the collection of comparable, defensible, and useful inventory and monitoring data for the species component of biodiversity.

This manual is one of the Standards for Components of British Columbia's Biodiversity (CBCB) series which present standard protocols designed specifically for group of species with similar inventory requirements. The series includes an introductory manual (Species Inventory Fundamentals No. 1) which describes the history and objectives of RIC, and outlines the general process of conducting a wildlife inventory according to RIC standards, including selection of inventory intensity, sampling design, sampling techniques, and statistical analysis. The Species Inventory Fundamentals manual provides important background information and should be thoroughly reviewed before commencing with a RIC wildlife inventory. RIC standards are also available for vertebrate taxonomy (No. 2), animal capture and handling (No. 3), and radio-telemetry (No. 5). Field personnel should be thoroughly familiar with these standards before engaging in inventories which involve either of these activities.

Standard data forms are required for all RIC wildlife inventory. Survey-specific data forms accompany most manuals while general wildlife inventory forms are available in the Species Inventory Fundamentals No. 1 [Forms] (previously referred to as the Dataform Appendix). This is important to ensure compatibility with provincial data systems, as all information must eventually be included in the Species Inventory Datasystem (SPI). For more information about SPI and data forms, visit the Species Inventory Homepage at:

It is recognized that development of standard methods is necessarily an ongoing process. The CBCB manuals are expected to evolve and improve very quickly over their initial years of use. Field testing is a vital component of this process and feedback is essential. Comments and suggestions can be forwarded to the Elements Working Group by contacting:

Species Inventory Unit

Wildlife Inventory Section, Resource Inventory Branch

Ministry of Environment, Lands & Parks

P.O. Box 9344, Station Prov Govt

Victoria, BC V8W 9M1

Tel: (250) 387 9765



Funding of the Resources Inventory Committee work, including the preparation of this document, is provided by the Corporate Resource Inventory Initiative (CRII) and by Forest Renewal BC (FRBC). Preliminary work of the Resources Inventory Committee was funded by the Canada-British Columbia Partnership Agreement of Forest Resource Development FRDA II.

The Resources Inventory Committee consists of representatives from various ministries and agencies of the Canadian and the British Columbia governments as well as from First Nations peoples. RIC objectives are to develop a common set of standards and procedures for the provincial resources inventories, as recommended by the Forest Resources Commission in its report "The Future of our Forests".

For further information about the Resources Inventory Committee and its various Task Forces, please contact:

The Executive Secretariat

Resources Inventory Committee

840 Cormorant Street

Victoria, BC V8W 1R1

Tel: (250) 920-0661

Fax: (250) 384-1841


Terrestrial Ecosystems Task Force

All decisions regarding protocols and standards are the responsibility of the Resources Inventory Committee. The current version of this manual was the result of the hard work and expertise of Markus Merkens (PAW Research Services) with valuable input from Dr. Charles Krebs (UBC), John Boulanger (Integrated Ecological Research), Todd and Linda Zimmerling (Applied Ecosystem Management), Dr. Tom Sullivan (Applied Mammal Research Institute) and Mark Fraker (TerraMar Environmental Research). Specialized methods for water shrews were provided by Lisa Hartman (Ministry of Environment, Lands and Parks).

Some of the background information and protocols presented in this document are based on Version 1.1 of this manual and the unpublished government report, Inventory Techniques for Small Mammals, prepared for the Resources Inventory Committee by Laura Darling (Ministry of Environment, Lands and Parks) with assistance from Ruth van den Driessche and Tom Ethier.

The Standards for Components of British Columbia's Biodiversity series is currently edited by James Quayle with data form development by Leah Westereng.


Table of Contents

Canadian Cataloguing in Publication Data





3. Protocols


Literature Cited

List of Figures

Figure 1. RIC survey design hierarchy for small mammals.

Figure 2. Diagramatic representation of study designs for RIC mark-recapture studies.

List of Tables

Table 1. Species covered in the small mammal inventory group.

Table 2. Types of inventory surveys, level of intensity and the data forms needed for a small mammal survey

Table 3. Recommended trap type, configuration, and marking requirements for various levels of inventory for shrews, voles, mice and rats.

Table 4. Inventory objectives and analysis methods for presence/not detected data.

Table 5. Inventory objectives and analysis methods for relative abundance data.

Table 6. Inventory objectives and analysis methods for absolute abundance data.

Table 7. Study design criteria for mark-recapture methods of inventory for small mammals.

Table 8. Sources for sample size calculations for mark-recapture population estimates.


[Back to TOC] [Previous] [Next]


HTML Created: August 98

Copyright ? 1998 Province of British Columbia

Published by the Resources Inventory Committee