Forest plantations are a relatively new environment in Chile, with impacts of different magnitude on different taxa. Birds are one of the taxa mostly used as ecological indicators to evaluate the effect of different types of disturbances, due to their level of specialization in the use of different microhabitats. We assessed the effect of the age of Pinus radiata plantations (2 sites of 8 and 12 years, respectively) and seasonal (three seasons) on the diversity of bird assemblages. The abundance of species from both sites was assessed through acoustic and visual survey records, which were also compared at trophic guild level. Differences were observed at both sites, with higher diversity calculated for Cerro Ñielol (8 years) compared to Rucamanque (12 years). In seasonal terms, diversity was not affected in Cerro Ñielol, while in Rucamanque significant differences were observed during fall. Guild composition of both localities also showed differences, resulting in higher diversity for Cerro Ñielol in most cases. Despite the fact that the younger plantation presented the highest diversity, elements associated with the landscape are discussed, as well as particularities in the use of space by the species.