Ozone gave no clear link to next-year survey absence on selected US bird routes in 1995-2023

We tested whether current ozone and seasonal warmth predict the absence of an accepted bird survey in the next year. We joined a published US Breeding Bird Survey panel to the full USGS survey log. The pooled model used 23,816 surveys on 2,000 routes. It included route-observer and state-year effects and survey and weather controls. At 75 F, the ozone estimate was +1.22 percentage points of absence per 10 ppb, with a 95% interval from -1.38 to +3.82. The ozone by temperature term was +0.12 percentage points per 10 ppb and 5 F, with an interval from -1.86 to +2.11. All eight intervals in four separate region and time samples included zero after correction. Route trends, closer monitors, and a broader survey outcome gave no clear link. This result does not show that missing surveys are random. Selected monitor coverage, missing controls, small western samples, and a linear model limit inference. This is an observation-process test, not a test of bird loss or climate-change effects. The package has the input panel, follow-up labels, source hashes, code, an independent numerical check, tables, and a figure.

observation bias · ozone · Breeding Bird Survey · survey absence · seasonal warmth · regional replication · null result