Hidden world of mice, voles and shrews revealed through a new approach

Thanks to the efforts of a team of researchers, the hidden world of British mice, voles and shrews has just opened to new audiences. Using audio recordings, the team developed an approach to help better understand the status and distribution of these easily overlooked species.

Although rarely seen, British mice, voles, shrews, rats and dormice occasionally reveal their presence through their vocalizations. A team of researchers has spent the past 18 months recording and studying these utterances to develop “acoustic classifiers” that can be used to detect the presence of various small mammal species in records from automatic recorders in the field. This approach could be particularly useful for determining the presence of various small mammal species in nature reserves or in places where development is planned.

To the human ear, the vocalizations made by small mammals may sound like a simple high-pitched squeak, but the calls are extremely complex indeed, extending beyond the realm of our hearing in the ultrasound, and showing great differences in structure. Small mammal vocalization serves a variety of purposes, including communication between parents and offspring and use in aggressive encounters. By examining the detailed nature of these various calls, the researchers were able to develop a solid library of calls that has now been shared through an article in British Wildlife Magazine and an online resource from the British Trust for Ornithology.

Harvest Mouse, Copyright Mark Hows, from the Surfbirds Galleries

Dr. Stuart Newson, lead researcher on the project, commented, “Our approach complements existing surveillance approaches for small mammals and adds data from many more locations for a range of species whose status information is difficult to obtain and, in many cases, missing or out of date. Collecting acoustic data for small mammals could be extremely inexpensive. small mammals often speak at night, and their calls are often collected as bycatch by the survey bats. By traversing these records through the BTO’s acoustic pipeline, small mammalian calls can be detected and the species identified. “

Dr. Newson continued, “This approach could aid conservation efforts by providing an economical and robust method for detecting the presence and abundance of small mammals like Hazel Dormice in forests or established Brown Rats on seabird islands.”

Huma Pearce, co-author, commented, “Small mammals provide vital ecosystem services including seed distribution, insect control, and soil structure and chemical composition management, as well as an important source of food for large numbers of predators such as owls. However, their value is largely overlooked as relatively few species receive legal protection. It is hoped that this novel approach to monitoring small mammals will improve our understanding of their distribution and abundance, and ultimately raise awareness of their importance in maintaining healthy ecosystem function. “