October–April precipitation gave no clear mean gain in fixed spatial predictions for ten duck taxa in 24 prairie strata, 2000–2019

We tested whether precipitation before May adds information about May duck distribution. We used ten duck taxa and 24 prairie strata from the Waterfowl Breeding Population and Habitat Survey. The reference model used previous duck shares, previous pond levels and fixed spatial preferences. The added term used October–April precipitation from NASA POWER at one point per stratum. We fitted separate models on 16 target years in 1982–1999 and kept them fixed. On 18 test years in 2000–2019, added precipitation decreased mean squared Hellinger error by 1.57%. The nominal 95% test-year block interval was −5.67% to +8.46%. Five taxon point gains were positive and five were negative. A shorter training period gave a larger gain, so the result depends on the fit history. Adding current May pond change decreased error by 20.69% under the same primary comparison. This test did not establish a mean gain from the precipitation term. The weather data are a retrospective reanalysis. We did not test real-time data availability, other weather models or causal habitat effects. The package preserves data, source records, code, predictions, figures and repeat checks.

waterfowl · species distribution · precipitation · wetlands · prediction · MERRA-2 · NASA POWER · reproducibility