Earlier Meadow Brown flight dates had no clear repeated next-year index link in four English tests, 1985-2023

We tested whether earlier Meadow Brown mean flight dates preceded higher next-year abundance in two English regions and two periods. We used 6,814 complete three-year site records and controlled current abundance, spring temperature, site and year effects. All four estimates were negative. Only southern England in 2005-2023 had an interval below zero after correction for four tests: -0.079 log index plus one per ten days earlier flight, with interval -0.147 to -0.011. That result lost the threshold when current abundance was omitted or first date replaced mean date. All four prior-year diagnostic intervals included zero. Thus the test did not establish a common benefit or cost of earlier flight. Small northern samples, selected complete records, missing visit histories and shared count errors limit the result. These are local timing associations after year effects, not causal climate effects or validated forecasts. Pollution was not tested. The package gives code, aggregate results, source hashes, retrieval steps and a figure. External records and annual derivatives remain outside the baseline publication.

phenology · Meadow Brown · UKBMS · observation bias · population abundance · spring temperature · temporal replication