Daily activities of Larus dominicanus (Lichtenstein 1823) at Saco da Fazenda, Itajai-Açu river estuary, Itajai, SC

The gull Larus dominicanus is one of the most common coastal seabirds of the Brazilian coast, being capable of using several habitats and types of preys. In that context the estuary of Saco da Fazenda is an important feeding area, bathing, cleaning of the feathers and resting. The objective of this work was evaluating the population structure and daily activity of L. dominicanus in the estuary. From February/2004 to January/2005, the gulls were monitored in monthly census in the Saco da Fazenda, with intervals of two hours among the census from the 6:00 am to 8:00 pm. The oscillations observed in the population of L. dominicanus along the year were considered significant, being higher in autumn. The occupation of the estuary started from the first hours of the day, culminating at the 2:00 pm. In the morning, the gulls were observed in feeding activity, following by the bathing, cleaning of the feathers and resting. In the afternoon the abundance reduced significantly, with the dispersion of the gulls to close areas to the Saco da Fazenda. The oscillations found in the abundance of L. dominicanus during this study can be attributed to events of the cycle of life of the gulls and the differences observed in the number of gulls along the day to the period of activity of the fishing fleet