Área de vida e comportamento de cuidado parental em Furnarius rufus (João-de-barro)

Abstract

During breeding season, reproductive pairs should ensure survival and growth of offspring, from nest defensing, feeding and accompanying the young after leaving the nest (Dale et al. 1996). The aim of this study was to define breeding season and estimate home range size of F. rufus, investigating whether there are difference between breeding season and non-breeding season and better understanding of the agglomeration of individuals in the study area (pers. Obs.). Futhermore this study aimed to investigate if there are differences in sexes of parental care in Furnarius rufus in rural area of northern Brazilian Wetland. The study was conducted in a Pantanal wetland region called Pirizal located in Poconé municipality, Mato Grosso, Brazil. We tested the hypotheses that: (1) home range size is smaller during the breeding season comparing to the non-breeding season, (2) there is an overlap of areas between neighbors, (3) the group of individulas of the studied areas have similar home range sizes; and that (4) parental care effort is the same between sexes. Adults were captured and banded for individual identification. Every observation session lasted two continuous hours and was conducted with a spotting scope and binoculars. The home range delimitation for the breeding pairs in the breeding season and in the non breeding season was made with the focal observation of individuals and applying the Minimum Convex Polygon (MPC) method. The observation sessions were repeated during each phase of parental care with an average of 2,47 ± 0,97 sessions per breeding pair. In nest construction and nestling feeding phases we monitored all behaviors of males and females and the amount of time they spent in parental behaviors. In the incubation phase we took note of which individual was in the nest and the frequency of this event, in order to know which had a higher participation in this phase. In Nest construction phase it was noted visits with nest material in its beak to see whether male and female differ in amount of nest material carried in the construction phase, and in cleaning the nest in feeding the nestlings phase. The home range size during the non-breeding season was significantly smaller than in the breeding season (p=0,01), this can be given to the flood pulse, where most of the home range of individuals are under water. With the home range maps created with the ArcGis® program it was possible to confirm that there is overlap in both seasons: in the breeding season there was a 5% overlap in the total area, and in the non-breeding season there was a 3,1% overlap in the total area. In all phases of parental care in F. rufus there was no difference in sex regarding any kind of behavior attached to parental investment, thus supporting the hypothesis that species without sexual dimorphism tend to divide equally parental care Two hypotheses of the study were supported, since there was overlapping areas of home ranges, and in all phases of parental care there was no difference between the sexes concerning any of the behaviors associated to parental investment. This study contributes with new information for this species, and also provides future studies with details about home range, territoriality and parental care, mostly for species in the Furnariidae family.