Limited effects of egg size on chick growth in the chinstrap Penguin Pygoscelis antarctica

We studied the effect of egg size on chick growth in the chinstrap penguin under natural nonmanipulative, conditions. The influence of egg size on chi ck mass at hatching, 15 and 45 days of age was analysed controlling for the effect of hatching date, as hatching date has been repeatedly associated w ith chick growth in this species. Egg volume explained 20% of the variation in the body mass of chicks at hatching. Its effect disappeared as chicks g rew, being statistically not significant at the age of 15 and 45 days. Egg volume asymmetry also had no role in determining chicks' growth asymmetries .