Programs are free with park admission; $5. Call 733-5153 for reservations and more information. "Ranger's Choice/Visitor's Choice," a 1 1/2-mile guided walk, is a chance to ask questions of a ranger with 20 years' experience, at 1:30 p.m., every Friday, through Feb. 28. A 1-mile guided "Night Walk" takes place at 7 p.m., Friday, Feb. 21. An experienced park ranger leads a 1-mile "Wilderness Ramble," at 2 p.m., every Saturday through Feb. 22. Volunteer naturalist Vicki Powers leads an easy, 1-mile, 2-hour walk in search of desert birds, at 8:30 a.m., every Sunday through Feb. 23. Park staff guide a 1-mile walk "Walk With the Past" to learn about the lives of the prehistoric Hohokam, at 2 p.m., every Sunday, through Feb. 23. A naturalist guides a 1-mile walk, "Walk With the Saguaros," to learn about the saguaro and desert trees, at 10 a.m., every Monday, through Feb. 24.