Virtual Posters

We studied the Antarctic terns breeding at Punta Crepin, King George Island (South Shetland Islands), during 2006, 2007 and 2008 seasons. We recorded a total of 12, 9 and 29 nests with eggs and/or chicks, respectively. Mean maximum and minimum diameters (cm) of nests were 17.95 ± 2.80 and 13.29 ± 2.34 in 2006, 11 ± 0.9 and 9.5 ± 0.94 in 2007 and 17.86 ± 4.6 and 14.4 ± 2.4 in 2008. Number of eggs per nest was 1.6 ± 0.52, 1.4± 0.52 and 1.1± 0.33 respectively. Mean dimensions of egg lengths (cm) were 4.51 ± 0.13 and 3.43 ± 0.20 (n=17) in 2006, 4.59 ± 0.1 and 3.35 ± 0.07 (n=14) in 2007 and 4.44 ± 0.2 and 3.3 ± 0.09 (n=26) in 2008. Mean volume (cc) for all eggs was 27.18 ± 3.48, 26.3 ± 1.22 and 24.7 ± 2.05, respectively. Not all one-egg clutches could be correctly classified as completed. During the season 2008, 58% of eggs were lost. Jablonski (1995) and Peter et al (1988) reported high percentage of losses in eggs (70 and 52 % respectively) in King George Island. The causes of losses in eggs were: Snowfalls and immediate neglect, predation by skuas, upper tidal levels, human disturbance and unknown reasons. 53% of losses are due to weather conditions in the season 2008, which was the main cause of losses in Admiralty Bay reported by Jablonsky (1995).