SUMMARY
Information on breeding biology of birds is fundamental for the understanding of life history evolution and conservation. This information is only beginning to accumulate for Neotropical birds but the southern subtropics are still overlooked. Here we describe the breeding biology of passerines in subtropical Brazilian Atlantic Forest. We monitored 265 nests of 38 species during the 2012–2013 breeding season. Breeding began in September, but some species started as late as December. Average breeding season length was 64 days, but varied broadly across species. Average clutch sizes ranged from two to five eggs. The breeding season phenology, clutch sizes, and nesting periods were similar to other two communities at the same latitude in Argentina. Our data contribute to the debate that the combination of small clutch sizes and short breeding seasons seen in subtropical South America challenges the tropical-temperate paradigm of life-history theory.