Cottonwoods and willows provide important habitat for game in desert environments, offering a ribbon of lush cover in an otherwise arid environment. Along the lower Colorado River, Bill Williams River National Wildlife Refuge has one of the last stands of natural cottonwood-willow forest that is part of a rich blend of varying habitats. There are places on the refuge where a cattail marsh sits next to a stand of saguaro cactus. This changing habitat supports a wide variety of species, including birds and upland game. The thick cover and good watering areas mean healthy populations of Gambel's quail, migrating mourning and white-winged doves, and cottontail rabbits, all of which may be pursued by hunters during Arizona state seasons (cottontail rabbits may be pursued only during the quail season). Hunters will also be rewarded with sightings of a wide variety of other wildlife, including mule deer, javelina, bobcat and dozens of migrating bird species.