Variação sazonal na abundância de Larus dominicanus (Aves, Laridae) no Saco da Fazenda, Itajaí, Santa Catarina

Abstract

ABSTRACT. Seasonal variation in the abundance of Larus dominicanus in the Saco da Fazenda, Itajaí, Santa Catarina, Brazil. The gull Larus dominicanus (Lichtenstein, 1823) is one of the most common coastal seabirds of the Brazilian coast, exploring several habitats and food types. The estuary known as Saco da Fazenda is an important feeding and resting area for the species. In this paper, we evaluate the population structure of L. dominicanus in this area. From February/2004 to January/2005, gulls were monitored in monthly census in Saco da Fazenda at intervals of two hours from 6:00 a.m. to 8:00 p.m. The fluctuations observed in the abundance of L. dominicanus along the year were significant, with the highest counts in March (181.6 ± 35.1) and the lowest in October (21.0 ± 4.9). Birds began occupation of the estuary in the first hours of the day, peaking at 2:00 p.m. (72.4 ± 14.2). In the end of the day the abundance reduced significantly with the lowest abundances at 8:00 p.m. (3.8 ± 3.0). Principal Components Analyses (PCA) revealed a positive correlation between the abundance of gulls and the temperature of the air. The fluctuations found in the abundance of L. dominicanus during this study can be correlated with different phases of the breeding cycle, while differences observed in the number of gulls along the day may be related to the activity of fishing fleet.

Behavioral aspects of waterbirds

“…The distribution of individuals throughout the day was similar to that obtained by Manoel et al (2011) at Saco da Fazenda, where the maximum relative abundance was at 14:00 hours and started to drop at 16:00 hours, which indicates birds leaving to their dorms (Branco, 2000;Ebert and Branco, 2009). The small difference in abundance and number of species between the recorded time intervals suggest that the sampled areas may be used as feeding sites throughout the day, since the abundance of prey influences the distribution of species (Hicklin and Smith, 1984;Kalejta and Hockey, 1994) and multispecific resting groups are concentrated in foraging areas (Warnock et al, 2001;Cardoso, 2011).…”

Pathogenic Bacteria Associated with Kelp Gull Larus dominicanus (Charadriiformes, Laridae) on the Coast of Santa Catarina State – Brazil

“…The species L. dominicanus is often observed feeding near the fishing companies in the state of Santa Catarina, where fish are handled, often without proper sanitization methods. Close contact of the gull at these places could potentiate the risk of cross contamination to humans through contaminated fish consumption (Ebert and Branco, 2009). Studies showed that the gulls contribute to the contamination of oysters in nature and in cultivation farms which could there by potentiate the transmission of diseases to humans (Albarnaz et al, 2007).…”

“…Schiefler and Soares (1995) argue that the gull L. dominicanus is one of the most common seabirds of Santa Catarina coast, being abundant in beaches, mangroves, islands and coastal lagoons. It is a very opportunistic species regarding feeding and habitat use, thus being able to occupy urbanized environments and also landfills near these (Ebert and Branco, 2009). The microbiota of birds is affected by many factors.…”

“…Wild birds, especially migratory waterfowl, are considered carriers or potential reservoirs of several pathogens, and may therefore play an important role in a disease epidemiology chain due to their ability to fly several regions in a short time span Benskin et al, 2009). In Brazil, recent studies have focused on reproduction and distribution (Barbieri 2008;Ebert and Branco, 2009;Branco, 2004;Branco et al, 2009), whereas the main studies elsewhere are related to diet (Schiavini and Yorio, 1995) and the species interaction with the man (Yorio and Quintana, 1996). In New Zealand, a study refers to the presence of nematodes, cestodes and trematodes in the digestive tract of gulls (Twentyman and Alley, 1999).…”

Birds of the Arvoredo Marine Biological Reserve, southern Brazil

“…In recent decades, the number of studies on seabirds at the RBMA and adjacent coastline has increased substantially (Bege and Pauli 1988;Schiefler and Soares 1994;Soares and Schiefler 1995;Efe et al 2000;Branco 2000;Branco and Ebert 2002;Branco 2003aBranco , 2003bBranco , 2004Branco et al 2004;Neves et al 2006;Branco et al 2007;Ebert and Branco 2009;Prellvitz et al 2009;Branco et al 2010a;Cremer and Grose 2010;Hogan et al 2010). Nevertheless, there still are few studies on landbird assemblage in islands at this region (Bege and Pauli 1988;Graipel et al 1997;Ghizoni et al 2013).…”