Scientific study supporting a rapid response to an early-stage occurrence of the red-billed leiothrix (Leiothrix lutea) in a Flemish dune ecosystem
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Details
The project focuses on a scientifically informed rapid response to the early-stage occurrence of the red-billed leiothrix (Leiothrix lutea) in a Flemish Natura 2000 dune area. Through targeted monitoring and analysis, the distribution and activity of the species are assessed to support a timely and effective response. Follow-up monitoring is used to verify continued absence after the intervention. The project contributes to early detection and knowledge development on invasive alien species and supports managers and policy makers in preventing establishment and further spread.Rapid response to the Japanese nightingale in the Flemish dunes
In September 2025, the first breeding record of the Japanese nightingale (Leiothrix lutea) in Belgium was recorded in the De Fonteintjes Natura 2000 dune area (Zeebrugge). This colourful songbird from subtropical Asia is an invasive alien species that has spread rapidly across southern Europe in recent decades, with large parts of Europe – including Flanders – providing suitable habitat. As the species competes with native songbirds and can promote the spread of invasive shrubs such as buckthorn and mahogany, swift action is crucial when such early establishment is detected. With support from IUCN Save Our Species, co-funded by the European Union, the Institute for Nature and Forest Research (INBO) therefore launched a project to investigate how this emerging population can be removed before it becomes permanently established.
Hilbran Verstraete installs an AudioMoth sound recorder in De Fonteintjes. © Margot Degreef
The first phase of the project consisted of intensive monitoring. A network of autonomous sound recorders (AudioMoths) continuously recorded the species’ presence, supplemented by spot and transect counts carried out by an experienced fieldworker. However, the species proved surprisingly difficult to detect: despite these efforts, and despite the area being frequently visited by birdwatchers, the birds went unnoticed for a long time. A sensitivity analysis, in which reference song from the XenoCanto database was mixed into our recordings, confirmed that our analysis reliably identifies the species. The absence of sightings therefore indicated a genuinely low occurrence, and not necessarily a shortcoming in the monitoring.
The first Japanese nightingale captured in Belgium, caught using mist nets at De Fonteintjes. © Axel Neukermans
A citizen sighting reported on waarnemingen.be in March 2026 marked the start of the trapping campaign. The following day, at least five birds were sighted and one individual was caught using mist nets – the first capture of the species in Belgium. This demonstrates how important an engaged network of citizen scientists is for a rapid response. After a long period without any sightings, the species reappeared in August, once again reported by a member of the public. We are therefore focusing on very intensive monitoring this autumn, with mist nets being deployed immediately as soon as birds are spotted.
Information panel at the edge of the reserve, with a QR code for further information and to report sightings. © Margot Degreef
Communication is also a key component of the project. We have placed information panels at the entrances to the area, informing visitors about the species and encouraging them to report sightings. Together with an article in the local Natuurpunt magazine and a project page on the INBO website, these initiatives are increasing local involvement in the early detection of invasive species.
With the support of IUCN Save Our Species, co-funded by the European Union.
| Status | Running |
|---|---|
| Actual start/end date | 05/01/2026 - 30/09/2035 |
Teams
INBO Research theme(s)
- Wildlife management
- Invasive species
Tags
- avifauna
- invasive
- management
- monitoring
- natura2000