A great deal of information about the migration of birds and the work being done to preserve and to study wildlife has been included in this story about a pair of whistling swans which became separated in their flight from Alaska south to Maryland. Cynda, the female, was wounded by a hunter and collapsed in Minnesotsa, where she was found with her cygnets by 10-years-old Bob Dean, who, with the help of an ornithologist, cared for her over the winter. Krugluk, her mate, had been flying ahead and was unaware of her plight. He continued with the flock to Chesapeake Bay but without Cynda became dispirited, would barely eat, and survived the cold weather only with the help of Jennie Pines, a 15-years-old who become fascinated with the swans. The descriptions of these rare swans are authentic and should interest anyone concerned with natural science. Much less realistically drawn than the swans are the two children who care for them. Jennie is suffering from an unrequited crush on an older boy, and Bob, who loves the great outdoors, is disturbed by his mother's desire to move to the city so he will be less isolated--oliche situations which are much more likely to lose the reader's attention than the informative materials about the swans. There is a list of ""Books for Further Reading,"" most of which are too technical for this age group.