Winter warmth gave no clear repeated delay in Orange-tip mean flight dates in England and Wales in 1985-2024

We tested whether mild winters were linked to later Orange-tip mean flight dates after control for separate March and April temperatures, spring rain, time, peak count and site effects. Four England and Wales samples in 1985-2004 and 2005-2024 used 19,259 site-years and equal annual total weights. December-February slopes were -2.33, -0.24, -1.58 and +0.04 days per degree C. Both early HAC intervals were below zero; both later intervals included zero. Delete-year jackknife intervals were wider and removed the clear early Welsh result. Six planned sensitivity fits gave no clear repeated winter delay. These results do not test cold duration or disprove chilling effects. Country weather, missing visits, selected sites, small annual samples and only eight early Welsh sites limit inference. The package gives code, source hashes, aggregate results and numerical checks. External records and derived panels remain outside the bundle.

phenology · winter warmth · Orange-tip · chilling · observation bias · regional replication · uncertainty