CORRELATIONS BETWEEN EGG CHARACTERISTICS AND LAYING ORDER IN THE STARLING (Sturnus vulgaris) IN NW CROATIA

Dolenec, Z.: Correlations between egg characteristics and laying order in the starling (Sturnus vulgaris) in NW Croatia. Nat. Croat., Vol. 10, No. 1., 11–17, 2001, Zagreb. This article analyses the effect of body weight and wing length of female starlings on clutch size as well as the effect of laying order on egg size. Egg length averaged 29.43 mm, egg breadth 21.32 mm, egg volume 6829 mm3, egg weight 6.92 g and egg shape index 1.38. There was no significant relationship between female body weight and clutch size and egg size (p >0.05). The same can be applied to the female wing length. A statistically significant positive correlation was found between mean egg volume and egg length (r =0.68; p<0.001; n =48) as well as egg breadth (r =0.87; p<0.001; n=48), egg length and egg shape index (r =0.81; p<0.001; n =48), whereas a statistically significant negative correlation was observed between egg breadth and egg shape index (r =–0.38; p<0.01; n=48). Generally, the laying order did not affect egg volume. According to the value of %D =–1.8 and the coefficient of egg weight variation (CV =9.39%) starlings follow the brood reduction strategy. The value of %D can be obtained by calculated the percentage of final egg volume in relationship to mean egg volume of the whole clutch (SLAGSVOLD et al., 1984).