This is the final weekend of the winter for tours of the historic Clock Tower and eagle viewing at the Mississippi  River Visitor Center at Lock and Dam 15 on Arsenal Island. Climb the stairs to the top of the tower for a spectacular view of the Mississippi River and watch for bald eagles.

Free tours will be given by a U.S. Army Corps of Engineers park ranger at 9 a.m. and 12:30 p.m. Saturday and Sunday, each lasting about 1½ hours. Tours begin at the visitor center on the western end of Arsenal Island. Advance registration is recommended at 309-794-5338.

By the numbers All about eagles

4 years: Time until a bald eagle reaches maturity and gets its trademark white head and tail.

8 feet: Wingspan of a bald eagle

12 pounds: Weight of average bald eagle

100 mph: Speed of a bald eagle while chasing prey.

2007: Year the bald eagle was removed from the Endangered Species Act.