The science of wildlife management is actually quite new. It is the third major phase of the original conservation movement. The first phase involved the preservation of wildlife through laws and hunting regulation. This phase was a reaction against the terrible destruction of many wild creatures. The second phase involved the control of certain birds and animals that were preying on other wildlife and causing their decline. However, the first two phases of the conservation movement had serious limitations. The new laws allowed certain animals to increase so much that they actually 'ate up' their habitat. Many of them starved to death because the land simply could not provide for them all. Something had to be done. This is how careful wildlife management came into being. One of the chief concerns of wildlife management is the protection and improvement of the natural habitat so that animals have enough food and water to survive. Wildlife management involves care of the soil to produce good vegetation. It involves care of plants and bushes, not only as a source of food, but also as protection. Animals needs cover to hide from their natural enemies and to raise their young safely. Just as crops are harvested, wildlife too must sometimes be 'harvested.' By allowing limited hunting and fishing, good management can control certain species that threaten to overpopulate their habitat. Another major part of the wildlife management is the increasing of certain species by artificial means. Some creatures, like the whooping crane, were brought back from the edge of extinction in this way. In order to save these species, members of wildlife teams have reared the young in the safety of research stations. The passage is mainly about ______.