“Riparian” means “streamside.” Riparian habitats are those found along rivers and other watercourses, and they have the greatest biodiversity of any habitat in the West. Colorado has fairly distinct low-altitude, medium-altitude, and high-altitude riparian zones. In the low-altitude zone, below about 6,000 feet, riparian habitats usually consist primarily of cottonwoods and other deciduous trees, often with associated underbrush. Characteristic birds include Downy Woodpecker, Eastern and Western Screech-Owls, White-breasted Nuthatch, Black-capped Chickadee, House Wren, Gray Catbird, Yellow Warbler, Yellow-breasted Chat, Black-headed Grosbeak, Song Sparrow, and Bullock’s Oriole. Animals include white-tailed deer, fox squirrel, and Virginia opossum.
In the medium-altitude riparian zone, rivers are lined with narrowleaf cottonwood, river birch, alder, willows, and the state tree, Colorado blue spruce. Typical birds of this habitat include American Dipper, Hermit Thrush, and Yellow-rumped and MacGillivray’s Warblers. Much other wildlife can be found here as well. Butterfly enthusiasts will find Weidemeyer’s Admiral and several species of swallowtail.
The high-altitude riparian zone consists mostly of low-growing willows, which sometimes form large swamps called willow carrs. In these areas one may find breeding Willow Flycatcher, Wilson’s and MacGillivray’s Warblers, and White-crowned, Fox, and Lincoln’s Sparrows. Beavers often dam the streams at this elevation, creating ponds that Moose may wallow in.
Wetlands provide habitat for a wide variety of birds. True marshes, usually dominated by cattails or bulrushes, provide breeding habitat for American Bittern, Sora, Virginia Rail, Northern Harrier, Marsh Wren, Common Yellowthroat, Red-winged and Yellow-headed Blackbirds, and Great-tailed Grackle. Some marshes in the Arkansas River Valley host breeding Black Rail. Various butterflies and other insects are found only in marshes.
Wet meadows differ from marshes in being less permanently flooded. They are usually dominated by low grasses or sedges. Wet meadows at middle to low elevations provide breeding habitat for dabbling ducks, Wilson’s Snipe and Savannah Sparrow, and they are often good for ibis in migration. In some parts of the state these meadows host breeding Sandhill Crane and Wilson’s Phalarope. They may also attract frogs and other amphibians.