Ozone and warmth gave no clear joint link to recorded bird species replacement in four US samples in 1995-2024

We tested whether prior seasonal ozone and warmth jointly predicted replacement of recorded bird species. We split annual species change into replacement and a remainder from unequal richness. We used the same published US bird survey pairs as a prior total-change study. Four East and West, early and late models controlled route-observer effects, state-year effects and survey conditions. Replacement interaction estimates ranged from -0.117 to +0.322 percentage points per +10 ppb ozone and +5 C. All four corrected intervals included zero. The pooled estimate was +0.183, with a 95% interval from -0.151 to +0.518. Separating the two components did not reveal a repeated positive interaction. This is a new test on reused records, not independent data confirmation. Incomplete detection, selected routes near monitors, seasonal averages and few western state clusters limit inference. The package contains exact input data, code, source hashes, component values, all model results and numerical checks.

birds · ozone · temperature · species replacement · nestedness · observation bias · null result