( aptive flock. Taken together the bene...)Removing egg from nest may help save endangered whooping crane

"Luckily, at the moment the program is so successful that there is no reason to collect more eggs," said Boyce. "But for Parks Canada to intervene with a formal policy to prohibit future egg collecting is inappropriate and flies in the face of the data, as we present in our paper."

Boyce suggests several reasons why a chick might survive when an egg is removed from a nest. Sibling aggression has been so strong that some chicks have been observed pecking the later-born bird to death. Also, a pair of chicks is more likely to attract the attention of a predator and parents can be more attentive if they only have a single chick to protect.

Even though long-term fitness is almost the same whether one egg or two is laid, the risk of extinction for the Wood Buffalo-Aransas whooping crane population is lowest when eggs are removed, says Boyce. He recognizes the need to minimize human influence in national parks, but says priority should be given to ensure persistence of threatened and endangered species so that diversity is not lost permanently. "Surely we cannot appreciate benefits to ecological-process management if components of the ecosystem are missing," said Boyce.