This year SOS is organising a county survey of Lesser Spotted Woodpeckers (LSW) and we are seeking volunteers to help. We will be using a novel approach, Passive Acoustic Monitoring which is something new and groundbreaking for SOS. As we all know LSW is now an elusive and challenging species but sound recording makes a county wide survey a realistic proposition for the first time for many decades.

Passive Acoustic Monitoring (PAM) involves deploying small recorders at selected sites recording and storing bird sounds either continuously or to a pre-determined schedule. The resulting recorded files are then analysed to identify all the calls and songs of the species being monitored. Automatic systems (such as the BTO Acoustic Pipeline, Chirpity or BirdNet) are used to process all the sound files and find the records of the species of interest – in the case of LSW, calls and drums. For the Sussex survey we will be using a bespoke woodpecker module developed on the BTO Acoustic Pipeline to analyse all the recordings to locate any LSW calls or drums.

We first tested the method at known LSW sites in the New Forest in 2024 and it was amazingly successful. Taking this forward in 2025, with Mark Mallalieu, we deployed five recorders at possible LSW sites in Sussex. With these we covered 33 locations and LSWs were detected at 23 of them (70%) – an exciting result which has already changed our views of the status of the species in the county. These results and similar ones from Hampshire, Somerset and Kent were published in a paper in British Birds before Christmas (Smith et al. 2025). This is all very timely with PAM likely to form the basis of a national LSW survey being planned by NE/RSPB/BTO for 2027/28 and will also likely be used by the BTO for some of the more challenging species as part of the next national atlas.

The LSW results from Sussex in 2025 were remarkable but the locations were not selected randomly across the county so it is not possible to extrapolate numbers beyond the sites monitored. It is probable that Sussex will emerge as one of the remaining important counties nationally for LSWs. In 2026 SOS have purchased six recorders (Wildlife Acoustics Song Meter Micros) and we are planning to run recorders at a random selection of around 100 1 km squares throughout the county. LSWs require wet woodland within a landscape with extensive broadleaved woodland cover. Bob Foreman at the Sussex Biodiversity Record Centre has kindly provided woodland cover data for Sussex at the 1km square level together with measures of wet woodland. With these data we have come up with a list of over 500 1km squares in the county with potentially suitable LSW habitat. We focussed on the areas north of the Downs given the paucity of LSW records from both the Downs and the coastal plain over the last couple of decades. Our target is to deploy recorders in 100 of the selected 1km squares this year. See the map for the locations of the selected 1km squares.

Organising a survey like this is new to all of us. To avoid having to transport recorders around the county we have recruited some ‘regional coordinators’ who will hold recorders, memory cards etc that they can supply to local volunteers. We are looking for volunteers to agree to collect the equipment from their local coordinator, deploy it at the agreed site(s) for five days or so, collect it and return to the coordinator. We can’t guarantee that you will see or hear a LSW but we are sure the recorders will detect quite a few. Full instructions and protocols will be available and we are planning to start deploying the recorders in mid-February and continue until the end of April by which time the LSW drumming and calling season will be over for the year.

If you are interested in helping with this important survey, please contact us at ken.smith.lsw@gmail.com or 07815 456280 and indicate the sites you are able to help with. If you happen to have your own recorder, which many people now do, we will be very happy to provide some help and guidance so you can use it as part of this survey.

Ken & Linda Smith

Reference
Smith K, Smith L, Addleton N, Clements R, Fisk S, Gillings S, Mallalieu M, Mathieson H & Robin A. 2025. Bioacoustics as a tool for the detection and monitoring of a scarce woodland bird – the Lesser Spotted Woodpecker. British Birds 118: 658-667.

This map shows the 100 1km squares selected to be surveyed using Song Meters in 2026.