Dr. Mark Boyce, from the Faculty of Science, studied the policy of removing from Wood Buffalo National Park one of two whooping crane eggs laid and raising it in a "foster-parenting" program. Cranes usually rear a single chick and the other dies to siblicide or is killed by a predator, such as the wolf or fox. The egg-removal program was initiated years ago by Ernie Kuyt, an Edmonton-based scientist who reasoned that one egg could be taken and used for artificial propagation programs. The idea was so successful, says Boyce, that the whooping crane's numbers have skyrocketed to over 200 birds in the original population and two new populations have been established elsewhere.
But Parks Canada prefers that no future egg collections occur in Wood Buffalo National Park due to concerns that egg removals may reduce the productivity of the whooping crane population and that more generally, human intervention and disturbance should be minimized. Boyce's research found, however, that taking one egg away actually increases the probability of nest success. His paper--co-authored by Subhash Lele from the U of A's mathematical and statistical sciences department as well as Brian Johns from the Canadian Wildlife Service-- is published in the December issue of Biological Conservation.
The last remaining whooping crane population nests in Wood Buffalo National Park and winters at the Aransas National Wildlife Refuge in Texas. At one point the bird's numbers reached a low of 16 in 1942 but the population has since increased to more than 200 birds. Not only has the Wood Buffalo-Aransas population been enhanced by the egg removal program but removing the eggs has allowed the establishment of additional populations like those in Wisconsin and Florida, and a sizable
Contact: Phoebe Dey
University of Alberta