Citation
Overview
Connecting Constable and Gainsborough Country is a DEFRA-funded Landscape Recovery project. This report describes the use of passive acoustic monitoring to assess the status and distribution of birds, bats, terrestrial small mammals, and bush-crickets across the Stour, Brett, and Box valleys in south Suffolk. The project supports habitat restoration and woodland connectivity, with a focus on rare or declining species of conservation concern, including the Hazel Dormouse, informed by robust monitoring.
In more detail
During 2024 and 2025, core surveys were conducted at 80 locations across arable (n = 21), grassland (n = 19), and woodland (n = 40) habitats. Static acoustic recorders were deployed during three spring and summer survey periods, with each site sampled for approximately one week per period.
Recording effort comprised 1,075 days of low-frequency (audible) recording across 72 survey days, targeting birds, and 1,362 nights of high-frequency (ultrasonic) recording across 89 survey nights, primarily targeting bats, with incidental detections of terrestrial small mammals and bush-crickets. Additional targeted acoustic surveys of Hazel dormouse were carried out at four sites in September 2025.
Following manual validation, 293,999 bird recordings and 751,128 ultrasonic recordings were confirmed. The surveys detected 107 bird species, including 26 Red-listed and 28 Amber-listed species, alongside at least 11 bat species, five small mammal species, and seven bush-cricket species. Notable records included Nightingale, Turtle Dove, and three Vulnerable or Near Threatened bat species (Barbastelle, Serotine, and Leisler’s Bat). Hazel Dormouse was detected at two of the core survey sites and one of the additional targeted sites.
Species accumulation curves indicated that sampling effort was generally sufficient to characterise community composition across habitats. Woodland sites supported a more distinct bird assemblage, while arable and grassland habitats clustered together and shared many species.
Statistical analysis identified 20 bird species as significant habitat indicators, including key farmland specialists (e.g. Skylark, Yellowhammer, Linnet) and woodland specialists (e.g. Great Spotted Woodpecker, Nuthatch, Treecreeper). These species are particularly valuable for long-term monitoring due to their strong habitat associations and reliable acoustic detectability. Quantification of acoustic activity provided further insights into habitat use and its seasonal variation for both birds and bats.
For bats, the ability to distinguish between echolocation calls, feeding buzzes, and social calls for several species was especially informative, revealing not only patterns of presence but also areas of concentrated activity. This approach offers a promising means of identifying important foraging and social sites and of improving understanding of bat behaviour across the landscape.
