Great Blue Herons, Feeding habits, Nest success
Nesting Great Blue Herons (Ardea herodias L.) were studied on Brinkman's Island near Cassville, Wisconsin and on Catfish Island near East Dubuque, Illinois during the breeding seasons of 1978, and 1980-1985. Eggshells and unhatched eggs dropped from nests indicated 94% (n = 1501) of the eggs hatched. Nests near Cassville and East Dubuque contained an average of 2.2 to 2.6 young sufficiently large to be visible from the ground and an average of 1.7 to 2.4 hatchlings survived to fledging, respectively. The larger heronry on Brinkman's Island fledged an average of 1.7 young per nest annually and continued to increase in size. The smaller heronry on Catfish Island fledged an average on 2.4 young per nest. Eighty-six fish of 24 species common to the Mississippi River were found beneath nests. Stomach contents of dead young found beneath nests contained crayfish, rodent hair, and fish.
Proceedings of the Iowa Academy of Science
©1986 Iowa Academy of Science, Inc.
Kaufmann, Gerald W. and Cawley, Edward T.
"Nesting Success and Feeding Habits of Great Blue Herons on the Mississippi River near Cassville, Wisconsin and East Dubuque, Illinois.,"
Proceedings of the Iowa Academy of Science, 93(4), 184-187.
Available at: https://scholarworks.uni.edu/pias/vol93/iss4/6