Abstract

The coastal wetlands of central Chile concentrate a large number of birds. It has been proposed that the seasonal variability of its abundance would depend mainly on fluctuations in migratory species. However, the population dynamics of birds in these systems have not been sufficiently studied. This work explores the little-known seasonal variations of the resident and migratory waterfowl of Petrel Lagoon, wetland of interest for the community of Pichilemu and with an increasing ecotouristic importance, aiming to analize the changes in abundance between seasonal periods for both groups of birds. Monthly bird censuses were conducted in 2014 and 2015. Then, in the analysis, a warm period from october to march and a cold one from april to september were considered. In addition, the birds were classified as Resident (rs) and Migratory Species, the latter being subdivided into Summer Visitors (VVs) and Winter Visitors (VIs). Regarding the results, according to expected for the VVs and for VIs, the abundance of the former group was higher in the warm period while the abundance of the second group was higher in the cold period. Nevertheless, marked seasonal preferences were observed for the resident species, which were more abundant in the warm period, suggesting as an explanation the existence of a displacement of birds from lower latitudes during the summer period (Local Dispersion of Resident Species). In particular, a remarkable abundance of Coscoroba coscoroba was reported. Based on the importance of this site for birds of diverse conservation status, it is proposed that Petrel Lagoon should have some form of formal protection, such as that of El Yali and Conchalí Lagoon.