A look back at the Museum's pioneering Bald Eagle breeding program developed in the mid-1970s. The program's success fueled similar captive breeding initiatives around the country, and became a model for contemporaries to expand upon. Bald Eagles, a once federally threatened species, are now flourishing in Ohio and across the nation.
In the 1600s, the Bald Eagle enjoyed a large breeding range that encompassed most of North America. Yet by the 1970s, its habitat and population were dangerously deteriorated. Populations reached a record low in 1979, when only four breeding pairs could be identified in Ohio. The natural habitats of the majestic birds were becoming sparse due to expanding neighborhoods and development along the shore. In addition to shrinking habitats, the rising use of pesticides such as DDT was poisoning their water supply and crippling surviving females' ability to produce eggs.
In the 1970s, Harvey Webster, then Curator of Live Animals (now Director of Wildlife Resources), worked alongside Wildlife Specialist Carl Lutzmann to initiate a captive breeding program with 3 long-term goals: (1) to develop techniques which might be used to enhance captive breeding of Bald Eagles; (2) to better understand the reproductive biology of eagles; and (3) to provide stock for placement in the wild.
The Museum acquired four Bald Eagles (Argus, Andy, Norbert Norton III and Martha) for the program, all of which came into captivity due to debilitating injuries, and could not be returned to the wild thereafter. Martha, the only female eagle, came into captivity as a very young bird with a wing injury. As a result, she identified with and bonded to humans instead of eagles. She very quickly developed a special bond with Lutzmann, who in essence became her human mate. Martha laid her first fertile egg sometime during the night of March 20, 1984—the hatching of which is chronicled in the excerpt below. The healthy eaglet was placed into a wild Ohio nest to be adopted by the adult birds there, who eagerly took him under their wing.
Revolutionary for its time, the Museum's Bald Eagle breeding program was one of only six in the country. Martha’s eaglet proved it was possible to restore populations of endangered species through captive breeding and release.
During the evening of April 24, 1984, a Bald Eagle chick struggled to free itself from the egg which was its nursery for the past 35 days. The tools the chick used for this laborious task were a sharp spur on its upper mandible, called the egg-tooth, and its hatching muscle, musculus complexus, apparent as an elongated bulge on the back of the head. The day before, the chick had used its egg-tooth to perforate an air cell in the blunt end of the shell. Thrusting its bill into this air cell, it was able to take its first breath. At this point, the chick started vocalizing in the shell and also began pipping (that is, creating a hole in the shell so that it might have free access to air) by using the powerful hatching muscle to drive the egg-tooth into the shell.
The pip appeared on an area close to the top of the shell near its equator. The chick worked several hours enlarging the pip hole. Cracks were seen radiating from the pip. Then in a burst of intense activity, which lasted 1½ hours, the chick turned in the shell, working a large fracture counterclockwise from the pip hole (as viewed from the blunt end). As the fracture grew to one-half the circumference of the egg, the chick flexed its body frequently against the shell, straining the eggshell and shell membrane. Finally at 10:03pm, with one last surge of activity, the eaglet emerged into the world.
At 3½ ounces and 6 inches in length, still wet with amniotic fluid and its large, bulging eyes looking somewhat contorted from its confinement, it bore no resemblance to the huge and powerful form of an adult Bald Eagle. In the ensuing hours as the eaglet rested, exhausted from its efforts, its downy feathers dried and fluffed out. Gradually, it became more alert and started begging for food. One might think this was a scene typical of a great eagle aerie overlooking a pristine shoreline in some rugged wilderness. But this was not the case. This tiny eaglet had just hatched in an incubator in the basement of The Cleveland Museum of Natural History.
Excerpt from the Summer 1984 issue of The Explorer, a magazine of the natural sciences by The Cleveland Museum of Natural History
