Dieta e comportamento de forrageamento do bigodinho Sporophila lineola (Aves: Thraupidae)

Abstract

The energetic and nutritional demands of animals vary, for example, across developmental stages, sexes, breeding, and wintering grounds. Foraging strategies reflect these ecological pressures, especially in migratory species and/or those exhibiting intersexual differences in parental care. This study investigated the foraging behavior and diet of the Lined Seedeater Sporophila lineola in two chapters. In the first chapter, we present the results of analyses of the foraging behavior of females and males of S. lineola during the breeding period (December to April) in Minas Gerais, southeastern Brazil. These analyses considered the distance traveled, time spent away from the nest, type of attacking maneuver, and food items captured. In the second chapter, we compare the foraging behavior between the breeding grounds (Minas Gerais) and wintering grounds (Amazonas), evaluating the type of attacking maneuver and the type of food items captured. We also conducted a review of the species’ diet, using field observations, stomach content analysis, and data from the literature. In the first chapter, males and females exhibited very similar foraging behavior, except for the longer foraging time displayed by females during the nestling period. Both sexes primarily consumed seeds of exotic grasses, indicating adaptation to disturbed areas. In the second chapter, significant differences were observed only in the Glean and Hang-down maneuvers, but there was no variation in the food categories consumed between the breeding and wintering grounds. Grass seeds dominated the diet, although the species consumed varied between grounds. The simple and minimally acrobatic attacking maneuvers adopted likely reflect habitat homogeneity and the abundance of static food resources. In conclusion, despite the different energetic and nutritional demands exhibited by male and female S. lineola, their foraging strategies are very similar. The high consumption of invasive exotic grass seeds at the breeding grounds and native grass seeds at the wintering grounds demonstrates the species' dietary flexibility. The consumption of arthropods plays a secondary role in the diet of S. lineola.