Breeding Biology of the Bridled Tern Sterna anaethetus on Nakhilu Island, Persian Gulf, Iran

The present study investigated some aspects of the breeding biology of the Bridled Tern Sterna anaethetus, a pan-tropical oceanic seabird on Nakhilu Island located in the northern Persian Gulf, Iran, during the breeding seasons of 2010 and 2011. Four stations with different types of vegetation cover were selected to estimate the effects of vegetation cover on their breeding biology. The length, width and depth of nests combined for 2010 and 2011 were 22.0±0.23 cm, 18.5±0.21 cm and 3.71±0.08 cm, respectively, and there were significant differences in nest dimensions between areas with different vegetation cover. More than 27% of nests (53 nestsout ofa total of 195 nests) were oriented towards the east while only 5.6% (11 nests out of a total of 195 nests) of nests were oriented towards the south-west and the west. The mean clutch size was calculated at 1.05±0.01 (N=4238) and there were significant differences between the mean clutch size within four categories of vegetation cover (χ23=11.884, N=219, P