How costly is clutch formation in the Audouin’s Gull Larusaudouinii?

During the Audouin’s Gull’s breeding season at the Ebro Delta in 1993, 24 fresh eggsfrom eight three-egg clutches (modal clutch-size) were collected at the peak of thelaying period. Eggs were processed to obtain formalin-fixed yolks, which were halvedand stained using the potassium dichromate method.

Xavier Ruiz et al, J. Avian Biol. 31: 467-575.