8 research outputs found
Reproduction and demographic trends of Sula Leucogaster at the Moleques do Sul Archipelago, Santa Catarina, Brazil
Ecologia reprodutiva de Sterna hirundinacea Lesson, 1831 e Thalasseus sandvicensis (Lathan, 1787) (Aves, Sternidae) na ilha dos Cardos, Santa Catarina, Brasil
Despite being widely distributed in South America, the South American Terns (Tierra del Fuego to Bahia and all around the Pacific coast to Peru), and Cayenne Terns, (from the Caribbean Islands to the region of Deseado Port), and having relatively large populations, little is known about the ecology of these species in the Neotropical region. The present study is a contribution to the knowledge of the reproduction and trophic ecology aspects. Samples were taken daily on the Cardos island, SC, Brazil, along 2003, 2005, from 2006 to 2008, aiming to characterize the reproductive ecology of these species. The season of 2003 began with the arrival of the first adults in mid-May, and in 2005 and 2006 occurred in late April, with the departure of adults in early October. 2486 nests of S. hirundinacea were recorded in 2005 to 1,852 in 2006, with average clutch size ranged from 1.45 in 2006 to 1.19 in 2003 and the hatching success in 2006 was estimated at 82.16%. While for Thalasseus sandvicensis in 2003, it took on average 23.5±0.2 days for the hatching of chicks, and success of 83.33%. Was recorded 6,248, 5,140 and 4,006 preys transported by S. hirundinacea and 1157, 628 and 98 by Thalasseus sandvicensis for the colony during seasons of 2003, 2005 and 2006, respectively. The delivery of food to the chicks occurred since the early hours of the morning until late afternoon. The first chicks hatched in July 2003 and June 2005 and 2006, with reproductive success for S. hirundinacea of 50.94%, 35.96 and 53.47%, and Thalasseus sandvicensis of 48.00, 29.94 and 5.00%, respectively. The highest growth rate for S. hirundinacea occurred in the first 20 days of life with small increments until the flight and subsequent abandonment of the island around 46 days in 2003, 45 in 2005 and 42 in 2006. The small size of the island, the human low pressure and little activity of the gull (Larus dominicanus), considered the main predator on the Brazilian coast, during the egg laying period, allowed the regular occupation, making it an important site for the conservation of these species.Universidade Federal de Sao CarlosOs trinta-réis apesar de serem amplamente distribuÃdos na América do Sul, (o trinta-réis-de-bico-vermelho ocorrendo da Terra do Fogo à Bahia e pelo PacÃfico ao longo da costa sul até o Peru), e o trinta-réis-do-bico-amarelo, (desde as Ilhas do Caribe até o sul da Argentina, Porto Deseado, Santa Cruz, 50ºS), e terem populações relativamente numerosas, tem muitos aspectos de sua ecologia ainda pouco conhecidos na região Neotropical. Foram realizadas amostragens diárias na Ilha dos Cardos, Florianópolis, SC, ao longo de 2003, 2005, 2006 a 2008, com o objetivo de caracterizar a ecologia reprodutiva dessas espécies. A temporada de 2003 iniciou com a chegada dos primeiros adultos em meados de maio, e em 2005 e 2006 ocorreu no final de abril, com a saÃda dos adultos no inÃcio de outubro. Foram registrados 2486 ninhos de S. hirundinacea em 2005 a 1852 em 2006, com número médio de ovos por postura variando entre 1,45 em 2006 a 1,19 em 2003 e o sucesso de eclosão em 2006 foi estimado em 82,16%. Enquanto que para Thalasseus sandvicensis em 2003, foram necessários em média 23,5±0,2 dias para a eclosão dos filhotes, totalizando um sucesso de incubação de 83,33%. Foram registradas 6248, 5140 e 4006 presas transportadas por S. hirundinacea e 1157, 628 e 98 por Thalasseus sandvicensis à colônia em 2003, 2005 e 2006, respectivamente. A entrega de alimento aos filhotes ocorreu desde as primeiras horas da manhã até o final da tarde. Os primeiros filhotes eclodiram em julho de 2003 e junho de 2005 e 2006, com sucesso reprodutivo para S. hirundinacea de 50,94%, 35,96 e 53,47%, e para Thalasseus sandvicensis de 48,00, 29,94 e 5,00%, respectivamente. A maior taxa de crescimento para S. hirundinacea ocorreu nos 20 primeiros dias de vida com pequenos acréscimos até o vôo e conseqüente abandono da ilha dos Cardos em torno do 46° dia em 2003, 45º em 2005 e 42º em 2006. O tamanho pequeno da ilha, a reduzida pressão antrópica e a pouca atuação da gaivota (Larus dominicanus), considerada o principal predador no litoral brasileiro, durante o perÃodo de postura, permitiu a ocupação regular deste sÃtio, tornando-o um local importante para a conservação dessas espécies
Reproductive Dynamics of Sterna hirundinacea Lesson, 1831 in Ilha dos Cardos, Santa Catarina, Brazil
In this work, we intend to describe the reproductive dynamics of Sterna hirundinacea in an island from South Brazil. We studied the reproductive biology of this species in its natural environment and provide data on their growth, survival, and reproductive success in Ilha dos Cardos, Santa Catarina, South Brazil. Samplings were carried out daily on the island throughout the reproductive seasons of 2003, 2005, and 2006 and the different stages of development of the chicks were characterized according to age, length of the beak, and plumage characteristics. We provide a basic equation Lm=167.91 (1-e-0.062t--0.23) to determine the approximate age of individuals using their body mass. The main cause of chick mortality on the island was natural (63.17% in 2003, 81.41% in 2005, and 79.96% in 2006), whereas predation contributed to mortality in a proportion of 38.83% in 2003, 18.59% in 2005, and 20.04% in 2006. The absence in the area of the chicks’ main predator, Kelp gull (Larus dominicanus), the large number of chicks that reached the final stages of development, and their reproductive success demonstrate that Ilha dos Cardos is an important breeding site for the species in southern Brazil