Aspectos sobre a biologia de daption capense na Ilha Elefante, Antártica

Abstract

Daption capense presents circumpolar distribution, being very abundant in the Southern Hemisphere Plays mainly in subantarctic islands, the Antarctic Peninsula and on the Continent. In Elephant Island, South Shetland Archipelago is also presented as breeding, but few data on its biology are found for this location. It is considered a small Procellariiform, and within this group, as the species shows that less dimorphism among individuals, but may have some difference as to morphometric measurements. Given the importance of morphometric variables in the understanding of biological aspects, particularly for determining sexes, the objective of this study is to (i) determine the sex of individuals of D. capense through molecular techniques and (ii) verify which morphological variables better distinguish males from females. The study was conducted on Elephant Island, between October and March, which corresponds with austral summer in the Southern Hemisphere, in 2010/2011 and 2011/12. Fifty-two adult D. capense individuals were captured: 32 in the austral summer of 2010/11 and 20 in the years 2011/12. Each bird was banded and measured. Blood samples were collected to be used in determining the sex of the individuals, which showed that 33 were males and 19 were females. The average and standard error were calculated for the morphometric measurements of the individuals before and after sex determination. Sexual dimorphism between males and females of D. capense was confirmed, and the significant morphometric variables for sexual determination were middle toe length (F=12.222; gl 1, 50; p=0.001) and beak height (F=18.931; gl 2, 49; p