Selection of nesting sites by the Pampas Meadowlark (Sturnella defilippii) in Pampas grassland, Argentina

ZALBA, SERGIO M.; COZZANI, NATALIA C.; SÁNCHEZ, ROCÍO

ORNITOLOGIA NEOTROPICAL

The Neotropical Ornithological Society

Lugar: Montreal, Canadá; Año: 2008 vol. 20 p. 35 - 46

1075-4377

Abstract. - The Pampas Meadowlark (Sturnella defilippii) is considered a vulnerable species by the IUCN (World Conservation Union) due its great range retraction and decrease in abundance over the last 100 years and also because it inhabits one of the most modified ecosystems in Argentina. Information about its nesting requirements, site fidelity and tolerance to current productive practices can be crucial for selecting an appropriate strategy for its conservation. This study was carried out on a breeding group found on a beef cattle farm in the southwest of Buenos Aires province. Plant species composition and vegetation cover at different heights were estimated at two scales, to identify possible parameters associated with nest site selection. The characteristics of these plots were compared with others selected at random in the immediate surroundings by discriminant analysis. Overall nest success was 0.29. Nests are associated with greater cover by Bunch Grass Stipa tenuis at the smaller scale, whereas in the larger plots the nests are positively related to areas of greater cover of S.tenuis, Aristida sp. and also greater percentage of bare ground. Therefore the species appears to choose to nest next to thick grass clumps, but at the larger scale prefers fairly open ground. The successful nests appear to be associated with lower percentages of bare ground in the smaller plots when compared to the predated nests. The Pampas Meadowlark requires tall clumps of grass in relatively open ground to nest. Intermediate levels of grazing might result in appropriate conditions for this species to nest.