A guided, volunteer-led tour is a good way to visit this wildlife refuge and birder's paradise. The peak seasons for bird-watching are spring and fall, when you can expect to see everything from pelicans and cormorants to Canada geese, snowy egrets, and some rarer species. Mid-October through May is the most pleasant time to visit, when it's cooler and the ever-present mosquitoes are least active.
Canoes can be rented at Martinez Lake Marina, 3½ miles southeast of the refuge headquarters. Kids especially enjoy the 1.3-mile Painted Desert Nature Trail, which winds through the different levels of the Sonoran Desert. From an observation tower at the visitor center you can see the river, as well as the fields where migrating birds like to feed. You can sign up for guided walks (including evening walks when the moon is full) from November through March (call ahead).