Heavy rains, cold temperatures and fog persisted throughout the winter and early spring of 1981-82 in the Sacramento Valley of California. Total rainfall in Chico, Butte County, California, for the period 1 March–15 April 1982 was 21.08 cm, 7.06 cm (50.4%) above normal for the entire months of March and April. Mean daily temperature during March was 11.1°C, a 0.2°C decrease from normal, and during April was 12.6°C, a decrease of 1.4°C (NOAA 1982a,b). During spring, 1982, we observed several incidents of mortality in swallows (Hirundinidae) which we believe were weather related.