Physical Sciences and Mathematics Commons^™

Record Fledging Count From A Seven-Egg Clutch In The Cooper’S Hawk (Accipiter Cooperii), Robert N. Rosenfield, Sarah A. Sonsthagen, Ann Riddle-Berntsen, Evan Kuhel

Nebraska Cooperative Fish and Wildlife Research Unit: Staff Publications

Cooper’s Hawks (Accipiter cooperii) typically lay 3–5 eggs per clutch, rarely 6 eggs, and there are 2 accounts of 7-egg clutches and 1 record of a maximum 8-egg clutch for the species. Brood sizes of 3–5 young are common and the previous maximum brood count is 6 young. However, in 2019, we found an urban nest in Stevens Point, Wisconsin, with 7 eggs that resulted in a record high of 7 fledglings. We genetically confirmed that the attending male sired all the offspring and the attending female laid all 7 eggs. Larger body size of the tending adults …