Trumpeter Swans in Chicago (10 images)

A female trumpeter swan nuzzles her newly hatched cygnet that just emerged from the shell at Lincoln Park Zoo in Chicago on May 29, 2008. This cygnet is slated to be released to the wild this fall as part of swan re-introduction and recovery program. Trumpeter swans were hunted to near extinction in 1900 and now, thanks to managed breeding and recovery efforts, these swans are thriving again in many parts of the Midwest. (UPI Photo/Greg Neise/Lincoln Park Zoo)

A female trumpeter swan swims with her newly hatched cygnets at Lincoln Park Zoo in Chicago on June 1, 2008. Trumpeter swans were hunted to near extinction by 1900 and now, thanks to managed breeding and recovery efforts, these swans are thriving again in many parts of the Midwest. (UPI Photo/Brian Kersey)

A male trumpeter swan swims with his newly hatched cygnet at Lincoln Park Zoo in Chicago on June 1, 2008. Trumpeter swans were hunted to near extinction by 1900 and now, thanks to managed breeding and recovery efforts, these swans are thriving again in many parts of the Midwest. (UPI Photo/Brian Kersey)

A female trumpeter swan swims with her newly hatched cygnet at Lincoln Park Zoo in Chicago on June 1, 2008. Trumpeter swans were hunted to near extinction by 1900 and now, thanks to managed breeding and recovery efforts, these swans are thriving again in many parts of the Midwest. (UPI Photo/Brian Kersey)