Behavior of the red-footed booby (Sulasula) in British Honduras

During three months of the breeding season in a colony of 3500 Red-footed Boobies (Sula sula) on 45½-acre Half Moon Caye, fifty miles east of Belize, British Honduras, that species’ little-known breeding activities were investigated. Feeding flights of boobies began leaving the caye before daylight and returned in the evening until after dark. Wind direction and velocity notably affected the mode of the birds’ departure but little affected their direction. Average flight-unit size was 2.41 birds. Contrary to published accounts, the boobies were able to take flight from the ground

Monitoring trends in bird populations: addressing background levels of annual variability in counts

ABSTRACT Point counting has been widely accepted as a method for monitoring trends in bird populations. Using a rigorously standardized protocol at 210 counting stations at the San Joaquin Experimental Range, Madera Co., California, we have been studymg sources of variability in point counts of birds. Vegetation types in the study area have not changed during the 11 years of the study, so annual variability in counts must refelect some normal range of variation associated with other factors. Here we show that counts of breeding species varied markedly from year to year, we suspect primarily in response to annual variation in precipitation and secondarily to variation in temperature. With ample data, practitioners can examine various periods of time for creating running averages to smooth background levels of annual variation in counts, thus establishing a baseline abundance for comparative purposes. We have explored running averages in our data, based on 2-to 7-year periods, with the objective of attaining