End wind gave uncertain prediction gains for bird taxon contrasts in Canada and the US in 2005-2024

We tested if end wind improved later-year estimates of the last-minus-first recorded bird taxon count. We used 19,734 surveys from Canada and the US in 2005-2024. Each target-year fit used only the prior 20 years and route-observer pairs with at least five earlier records. The baseline included pair effects, state trends and survey controls. Adding linear end wind reduced estimated mean squared error by 1.1-3.0% in four country-period samples. All four primary adjusted intervals included zero. A planned model with separate wind categories gave a clear gain only in the later US sample. These results show small estimated gains with material uncertainty. They do not show that wind has no effect on detection. Selected long observer histories, routine survey weather, few test years, overlapping training windows and approximate score intervals limit inference. These are estimates made with known survey conditions, not forecasts before field work or causal climate and pollution effects. A full raw-data repeat gave identical predictions and scores. The package preserves the panel, predictions, code, source hashes, checks and a figure.

observation bias · bird surveys · wind · temporal validation · prediction · recorded richness · Breeding Bird Survey · regional replication · uncertainty