Variation in weight and composition of Red-winged Blackbird eggs

Abstract
To investigate variation in egg weight and composition we collected and analyzed 38 Red-winged Blackbird (Agelaius phoeniceus) eggs. The composition of Red-winged Blackbird eggs was very similar to that reported for Brown-headed Cowbird (Molothrus ater) eggs. Egg weight is a good predictor of total energy (kJ) in blackbird eggs as those two variables were highly correlated (r2 = 0.66). Weight of Red-winged Blackbird eggs did not change over the breeding season.