State deletion tests gave no clear period change in seasonal ozone by warmth slopes in US bird records from 1995 to 2024

We tested whether an ozone by seasonal warmth slope in recorded bird richness changed between 1995-2009 and 2010-2024. Four published US Breeding Bird Survey samples contain 30,986 distinct surveys on 2,019 routes. We fit the source model with observer and survey controls. We kept dependence across periods within states and refit the model after each state deletion. The western later-minus-earlier estimate was +0.776 recorded species per 10 ppb ozone and 2 C warmth. Its state jackknife interval was -0.799 to +2.351 after correction for three comparisons. The eastern change was -0.231 (-1.027 to +0.565). West change minus East change was +1.006 (-0.837 to +2.849). Route trends gave the same lack of a clear change. The early western cell slope stayed -0.551, but its four-test interval included zero with the jackknife. These results do not establish equal slopes or no joint environmental effect. Few western states, selected coverage, exposure error and detection bias limit inference. This is a reanalysis of one data system, not an independent biological replication or a test of causal climate change. The package gives the exact panel, source hashes, all 198 deletion fits, covariance evidence, code, figures and offline checks.

ozone · seasonal warmth · birds · recorded richness · period change · regional comparison · state jackknife · observation bias · cluster covariance · Breeding Bird Survey · null result