Egg size of the Common Tern Sterna hirundo in Slovenia

Abstract

Clutch size and egg size of the Common Tern Sterna hirundo was studied in Slovenia. The total number of eggs measured was 242 from 90 nests. Among 90 complete clutches, 53.7% had three eggs. Density of breeding pairs had no effect on the clutch size. The largest eggs were found in clutches with two eggs. Egg length averaged 41.23 mm, egg breadth 30.07 mm, egg volume 19.52 cm³ and egg shape 0.73. No significant relationship was found between egg size (volume, breadth, length) and latitude and longitude (this study and literature data) within Europe.