Meteorological influence on a population of Sula leucogaster (Aves, Sulidae) at an Archipelago in the southern of Brazil

Abstract

The Moleques do Sul Archipelago has great importance for seabirds on the Brazilian coast as it houses breeding populations of various species. This archipelago represents the southern limit for the breeding colonies of the brown boobies (Sula leucogaster). In order to verify the influence of environmental factors on the abundance of adults and nestling of a Sula leucogaster population, we collected population data of this species in the archipelago between 2002 and 2007 for comparison to climatological data of the region. We generated seven multiple regression models to confront sex, age, number of nests and specimens, as well as adult and offspring mortality, to temperature, relative humidity, precipitation, atmospheric pressure on sea level and wind speed. Results showed that adults were positively related to average wind speed and negatively related to atmospheric pressure. Pressure also negatively influenced offspring, whereas number of nests was negatively affected by average wind speed. Adult and offspring mortality could not be explained by the variables. The correlations found in this study corroborate literature information for other researches on seabird in islands.

Keywords: brown booby, climate, islands.