Valley of the Cranes

My husband and I went down to the San Luis Valley, in south central Colorado, last weekend. We’ve been down there to see the sandhill crane migration several times in the last few years (Minature Upslope Storm), and it is always an amazing experience.

Twenty thousand cranes pass through the San Luis Valley in late February  to mid March.

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An equal number of other water birds — Canada and snow geese, a wide variety of ducks, and great blue herons, join the cranes as they pass through the Valley in one of the last great migrations of the lower 48. All these birds come for the food produced in the Valley’s marshy wetlands. Once they’ve built up their reserves, they’ll be on their way again, north to their breeding grounds that stretch from northern Colorado, into Canada, Alaska, and for some hardy birds, Siberia.

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Two adult sandhill cranes feed in a wetland.


Sandhill cranes are tall birds, long legs and neck taking them to 3 1/2 feet high, with a wingspan up to 6 feet across. They are grey, with brown mottling across their wings. Adults have a red patch above their eyes.

These beautiful birds mate for life, or at least long-term. They show their attraction to their mates by dancing, jumping and bowing.

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This high jump may be intended to intimidate rivals.

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These two cranes reinforce their bond with an upright wing spread.


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While the bird second from left does a “ruffle bow” the bird on the far right spreads its wings.

These beautiful displays have earned cranes a place in the hearts of people from many different cultures.

For all that their visual displays are a feast for the eyes, though, I think the thing that stunned my husband and I the most was the deafening noise that 2000 cranes make when they lift-off together. The thousands of birds calling could be heard from over a mile away.

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The noise these birds made was incredibly loud from over a mile away.


Minature Upslope Storm

My husband and I took a quick trip to the San Luis Valley of southern Colorado last week to see the largest migration left in North America — The Sandhill Cranes! Up to 20,000 Cranes and 20,000 other ducks, geese, coots, plovers and any other type of waterbird that you can imagine migrate through the San Luis Valley from February to April. They stop to fuel up in the rich salt marshes for their trek to Canada, Alaska and even Siberia. When they move on depends on the weather.

Unfortunately, by the time we got there, the Cranes had left the Valley.

But the San Luis Valley is such an interesting place that we found plenty of other things to keep us interested. One of the most interesting that we saw was purely by chance — a cloud getting caught on the top of Blanca Peak.



Warm moist air runs into 14,345 foot Blanca Peak. See how the cloud gets higher as it gets closer to the Peak? It is probably snowing at the summit. Then, once it’s over the top, POOOF! The cloud is gone.


This is actually a small upslope storm created as warm moist air coming up from the south (right) is forced to rise to get over the mountain. As the air rises, it cools. As it cools, it forms a cloud. Once the moist air is over the top, it can expand again and it evaporates. Climate people call this orthographic lift.

March through May is the season of upslope storms in Colorado, as warmer temperatures begin to pump air up from the Gulf of Mexico onto the Great Plains and from the Pacific into the Four Corners and San Juan Mountains. The process is exactly the same as what you see here, in miniature. These spring storms bring Colorado most of our moisture, and account for most of our snowpack.