Bird activity levels related to weather

Abstract

The Breeding Bird Survey data bank serves as a primary source for studying effects of sky cover, wind speed, and temperature on bird census results. Other standardized methods, such as spot-mapping (Breeding Bird Census), point counts, banding, and the Winter Bird Survey, provide additional, but limited, means of assessing effects of weather. Numbers of songbirds detected are generally inversely correlated with wind speed, but hawks often are seen in larger numbers on windy days. Rain greatly reduces the numbers of birds detected. Cloud cover has relatively little influence on early morning bird counts during the peak of the breeding season. Fog selectively favors auditory detections of some species. Counts of many species are correlated with temperature, but effects are minor unless temperatures are extreme. Under marginal weather conditions, total species observed may be nearly normal, whereas number of individuals observed is reduced, as is the opportunity to record simultaneous registrations