Deadman Creek artesian water, Great Sand Dunes National Park, Medano Ranch, San Luis Valley, Colorado. (Dunes171)
Dry wetland on Medano Ranch, Great Sand Dunes National Park, San Luis Valley, Colorado. (Dunes092)
Aerial view of Great Sand Dunes National Park, San Luis Valley, Colorado. (Dunes036)
Long-billed Dowitcher, Blanca Wetlands, San Luis Valley, Colorado. (Dunes116)
American Avocet and other shorebirds at Blanca Wetlands, San Luis Valley, Colorado
Wilson's Phalarope with American Avocet and White-faced Ibis at Blanca Wetlands, San Luis Valley, Colorado
American White Pelican at San Luis Lake next to Great Sand Dunes National Park, San Luis Valley, Colorado
Ancient matate discovered at Great Sand Dunes National Park, Medano Ranch, San Luis Valley, Colorado. (Dunes094)
Swirling Aspen Leaves, San Luis Valley, Colorado
Fall aspen leaves float on top of a calm pool of water. San Luis Valley, Colorado
Red aspen after autumn snowstorm in Colorado's San Luis Valley
Autumn color and snow-capped peaks complete the picture of spectacular Great Sand Dunes National Park, Colorado. (Baca016)
Snow on fall aspen trees along creek, San Luis Valley, COlorado
Elk Herd on Medano Ranch, Great Sand Dunes National Park, San Luis Valley, Colorado. (Dunes093)
Elk (Cervus elaphus) herd on Medano Ranch, Great Sand Dunes National Park, San Luis Valley, Colorado
Artesian Big Spring Creek flowing through Great Sand Dunes National Park on the Medano Ranch in the San Luis Valley, Colorado. (MedanoZapata008)
Bison bulls in front of Sand Dunes, sand dunes, San Luis Valley, Colorado
Bison Herd in front of sand dunes, sand dunes, San Luis Valley, Colorado
Bison bulls in front of Sand Dunes, sand dunes, San Luis Valley, Colorado
Bison Herd on frosty morning, Medano Ranch, Great Sand Dunes National Park, San Luis Valley, Colorado
-25F degrees shows the song in the air from a backlit Red-winged Blackbird. Monte Vista National Wildlife Refuge, San Luis Valley, Colorado
Broad-tailed Hummingbird feeding at Rocky Mountain Bee Plant (Cleome serrulata) at Great Sand Dunes National Park in Colorado's San Luis Valley
Checker Mallow wildflower, San Luis Valley, Colorado, Great Sand Dunes National Park. (Dunes061)
Prairie Sunflowers growing on sand dune at Great Sand Dunes National Park, San Luis Valley, Colorado. (Dunes081)
Coyote Tracks and Prairie Sunflower at Great Sand Dunes National Park, sand dunes, San Luis Valley, Colorado
Dramatic Cumulus Clouds over the San Luis Valley, Colorado
A handful of prairie sunflowers grows into the dunefield. Great Sand Dunes National Park, San Luis Valley, Colorado. (Dunes016)
Dust Storm approaching Great Sand Dunes National Park, San Luis Valley, Colorado. (Dunes017)
Elk Herd on Medano Ranch, Great Sand Dunes National Park, San Luis Valley, Colorado. (MedanoZapata017)
Elk (Cervus elaphus) herd on Medano Ranch, Great Sand Dunes National Park, San Luis Valley, Colorado
Great Blue Heron in wetlands near Great Sand Dunes National Park, sand dunes, San Luis Valley, Colorado
Flock of Sandhill Cranes parachuting in for a landing at sunset, San Luis Valley, Colorado
Flock of Sandhill Cranes parachuting in for a landing at sunset, San Luis Valley, Colorado
Blowing sand, Great Sand Dunes National Park, San Luis Valley, Colorado. (Dunes030)
Rainstorm at sunset, Great Sand Dunes National Park, San Luis Valley, Colorado. (Dunes058)
Visitors to Great Sand Dunes National Park enjoy playing in shallow Medano Creek and climbing the 700 foot high dunes. San Luis Valley, Colorado. (Dunes001)
Prairie sunflowers in Great Sand Dunes NationalPark, San Luis Valley, Colorado. (Dunes073)
Sunset at Great Sand Dunes National Park, Colorado. (Dunes062)
Great Sand Dunes National Park, Colorado. (Dunes007)
Interdunal wetlands adjacent to coppice dunes, Medano Ranch, Great Sand Dunes National Park, Colorado. (Dunes046)
Kangaroo Rat tracks in the sand, Great Sand Dunes National Park, San Luis Valley, Colorado. (Dunes038)
Kit Carson Peak and Challenger Point in the Sangre de Cristo Range are part of Great Sand Dunes National Park. San Luis Valley, Colorado. (Dunes027)
Long-billed Dowitcher, Blanca Wetlands, San Luis Valley, Colorado
A marsh wren sings a territorial song in a Valley wetland.
Migrating female western phalaropes stopping over at Blanca Wetlands, San Luis Valley, Colorado
Herd of Mule Deer bucks (Odocoileus hemionus) in prairie sunflowers at Great Sand Dunes National Park, San Luis Valley, Colorado
Mule Deer (Odocoileus hemionus) in prairie sunflowers, Great Sand Dunes National Park, San Luis Valley, Colorado
Mule Deer (Odocoileus hemionus) tracks filled with narrow-leaf cottonwood leaves in autumn. Great Sand Dunes National Park, San Luis Valley, Colorado
Northern Pintail Ducks and Greater Sandhill Cranes during spring migration. Monte Vista National Wildlife Refuge, San Luis Valley, Colorado
Prairie sunflowers and muhly grass, Great Sand Dunes National Park, San Luis Valley, Colorado. (Dunes063)
Rio Grande below Sangre de Cristo Mountains, The Rio Grande originates at the north end of the San Luis Valley, Colorado
Snipe in wetlands, San Luis Valley, Colorado
Snipe in wetlands, San Luis Valley, Colorado
Sand Creek, Great Sand Dunes National Park, San Luis Valley, Colorado. (Dunes090)
Great Sand Dunes National Park, San Luis Valley, Colorado. (Dunes012)
Blowing Snow, Great Sand Dunes National Park, San Luis Valley, Colorado. (Dunes034)
Flock of Sandhill Cranes migrating through the San Luis Valley in spring. Monte Vista National Wildlife Refuge, Colorado
Greater Sandhill Cranes leave night roost as sun rises through fog. Monte Vista National Wildlife Refuge, San Luis Valley, Colorado
Sand Treader, Camel Cricket, Great Sand Dunes National Park, San Luis Valley, Colorado
"Baskets" on legs of Sand Treader Camel Cricket, Great Sand Dunes National Park, San Luis Valley, Colorado
Reflection of full moon over San Luis lake, Great Sand Dunes National Park, San Luis Valley, Colorado. (Dunes037)
Short-horned Lizard, sand dunes, San Luis Valley, Colorado
Snowy Egret., Blanca Wetlands, San Luis Valley, Colorado
The Great Sand Dunes Tiger Beetle is endemic to the Valley. (AsstCritters044)
The Great Sand Dunes Tiger Beetle (Cicindela theatina) is endemic to the Valley
Great Sand Dunes Tiger Beetle (Cicindela theatina), Great Sand Dunes National Park, San Luis Valley, Colorado
Dunes and Sunflowers in Great Sand Dunes National Park, sand dunes, San Luis Valley, Colorado. (Dunes020)
Migrating female western phalaropes stopping over at Blanca Wetlands, San Luis Valley, Colorado. (Dunes067)
Wheeler is formed by erosion of volcanic tuff and ash. San Juan Mountains at the edge of the San Luis Valley, Colorado
White-faced Ibis in Blanca Wetlands, Bureau of Land Management, San Luis Valley, Colorado. (Dunes071)
White-faced Ibis in Blanca Wetlands, Bureau of Land Management, San Luis Valley, Colorado
Foster Whooping Cranes in San Luis Valley
Foster Whooping Cranes in San Luis Valley
Foster Whooping Crane in San Luis Valley
A flock of phalaropes stops at a wetland on their migration through the San Luis Valley.
Migrating flock of Wilson's Phalarope, San Luis Valley, Colorado
Entrance to Wolf Spider hole in sand, San Luis Valley, Colorado