The City of Nyon recorded 322 rook nests on its territory in 2026, a slight decrease from the 335 nests identified in 2025, according to a recent municipal study. While this marks only the second decline since monitoring began in 2017, the city’s rook population has more than doubled in ten years, growing at an average annual rate of 10.9%. Authorities are now using these findings to shape targeted intervention strategies, as the birds appear to be redistributing into peripheral sectors.
Did You Know? The rook population in Nyon has surged from 127 nests in 2017 to 322 in 2026, representing a significant long-term growth trend despite the minor year-over-year reduction.
How effective were the experimental deterrents?
Experimental measures deployed in the lower Cossy sector proved effective in the short term but highlighted potential displacement issues. By using a combination of nest dismantling, visual deterrents, and falconry with a Harris hawk, the city successfully cleared the priority zone of all nests, which had held more than 60 the previous year, according to the city’s report.
However, observations indicate that rooks may quickly reoccupy areas once intervention stops. Furthermore, there is a risk that these efforts simply push the birds into neighboring sectors, as evidenced by a rise in nest counts in areas like the Boiron and the Vuarpillière.
What impact does rook noise have on residents?
Acoustic measurements and an Unisanté health survey confirm that noise from rook colonies affects the quality of life for nearby residents. The study recorded average noise levels between 53 and 59 dB(A) for exposed homes, with peak noise reaching 70 dB(A) just ten meters from the nests.
These noise levels, which last from 5:30 a.m. until 9:00 p.m., are comparable to nighttime traffic noise on a busy road. Nearly 600 households participated in the Unisanté survey, which found that perceived disturbance intensifies with nest density and proximity, potentially impairing sleep quality in a manner similar to traffic noise.
Expert Insight: While targeted deterrents like falconry can provide immediate relief for specific residential zones, the tendency for these birds to relocate suggests that long-term success requires a city-wide strategy rather than isolated efforts in single neighborhoods.
What happens next for Nyon’s rook management?
The City of Nyon plans to use the data from its 2026 study to coordinate future actions with the Vaud Cantonal Directorate General of the Environment (DGE). Future interventions will prioritize sectors that combine high nest density with proximity to residential housing.
These findings could also influence potential changes to federal law. Authorities are considering whether to advocate for an adjustment to the legal framework, specifically regarding the protection period during the rook nesting season. A final report featuring operational recommendations is scheduled for publication in October 2026.
Frequently Asked Questions
Why did the number of nests decrease in 2026?
The city recorded 322 nests compared to 335 in 2025. While this is only the second decrease since 2017, the report notes a redistribution of colonies, with significant drops in the Cossy and Combe sectors and increases in peripheral areas like the Boiron and the Vuarpillière.
Are the deterrent measures permanent?
No. Observations show that rooks can rapidly re-establish themselves in areas once intervention efforts cease. Data currently available does not establish a definitive long-term link between the city-wide population changes and the specific deterrent measures used.
How loud are the rook colonies?
Average noise levels near the colonies range from 53 to 59 dB(A), with peaks up to 70 dB(A). These levels are comparable to the noise generated by traffic on a major road at night.
How should a city balance the protection of urban wildlife with the noise-related health concerns of its residents?
