Seasonal ozone and warmth gave no clear common link to next-year survey loss on US bird routes in 1995-2023

We tested whether seasonal ozone and warmth jointly predicted the lack of an accepted bird survey in the next year. We used 25,803 accepted US Breeding Bird Survey route-years on 2,191 routes, with a published pollution and weather panel and an independent outcome match to the raw survey register. Four East and West, early and late models used route and state-year effects and survey controls. Interaction estimates ranged from -4.45 to +3.38 percentage points per +10 ppb ozone and +5 C seasonal mean maximum temperature. All four corrected intervals included zero. The pooled estimate was -0.14 points, with a 95% interval of -2.94 to +2.65. Route trends, route-observer effects and closer monitors did not establish a common interaction. This result does not show that survey loss is random. Selected routes, coarse exposures, wide intervals and few western state clusters limit inference. We do not measure bird loss or causal climate effects. The package includes code, the model panel, raw source hashes, validation and reproduction instructions.

ozone · survey coverage · observation bias · Breeding Bird Survey · temperature · null result