Sand Hill Cranes at Monte VIsta National Wildlife Refuge, Monte Vista Colorado by Alan Sharp

Nikon D700

"Late in February, sandhill cranes, the San Luis Valley’s oldest visitors, begin their annual trek from south to north, stopping off near the Monte Vista National Wildlife Refuge ( www.fws.gov/refuges/profiles/index.cfm?id=65511  ) to load up on fuel." Tens of thousands of these magnificant 4 foot tall birds with 6 foot wingspans rest refuel and court here for three or four weeks before continuing their migration north to Idaho. The rangers told us there were more than 24,000 cranes around the refuge this year. They sleep all night on one leg in the very shallow water. start waking up before sunrise. lots of noise, (grumbling I think). and then lift off as a group to take a morning constitutional for a few minutes. They fly a large loop for five or ten minutes then land and get down to the serious business of eating and building up stores for the second half of their journey . They fly again at dusk . Getting good images requires a bit of luck as the large groupings move around .
I shot this gigapan after their evening flight when the birds were settling down for the night. Since the images were captured from left to right you can see how dusk overcame us by the time the camera made it all the way to the right.

Straight out (ENE, 79 degrees) from camera position is the Mount Blanca Massif (14,345 ft (4,372 m)) 39 miles away in the Sangre de Cristo range

There are some great videos of the cranes flying at www.youtube.com/watch?v=xpXDTNT7zsY  and www.youtube.com/watch?v=pPZ6xZb9Ogg&feature=related 
zoom in there's lots to see

Camera placement for this shot
37°27'35" N 106°08'25" W elev 7659 ft.