Summer rain changes had no clear repeated link to insufficient butterfly visits in England and Wales in 1985-2024

We tested whether wetter summers predicted more insufficient-visit flags for Ringlet and Meadow Brown. We used 48,817 matched site-species-year pairs at 2,886 sites in England and Wales. Four models used separate country records in 1985-2004 and 2005-2024. We averaged changes in the published flag for the same units and controlled temperature change and time. Rain slopes ranged from +1.01 to +4.66 percentage points per 100 mm increase. All four intervals adjusted for four tests included zero. Thus the test did not establish a repeated rain effect on this observation measure. Early Wales had few records and an unstable slope sign. The data condition on source rows in both years and lack visit schedules. Country weather, short time series, detection and changes in recording limit inference. The study does not estimate population loss, pollution effects or causal climate change. The package preserves source rows, weather, hashes, code, checks and a figure.

butterflies · observation bias · rainfall · missing visits · UKBMS · matched changes · null result