Birds and More | All Blogs


CRANES!

By Nic.Korte

   Western Colorado has two types of long-legged wading birds: herons and cranes. The similarities, however, are superficial. They are not closely-related.

   Our area is poor for heron diversity (the subject of the next blog), although, if lucky, one might see as many as 6 of the world’s 64 species over the course of a year. In contrast, we only have one of the world’s 15 species of crane, the Sandhill—but for much of the year, we have thousands of them. If you want to see herons, go where there are more wetlands, particularly coastal areas. (I photographed this Reddish Egret near San Diego) 

If you want to see a lot of cranes in the United States, you might as well stay close to home.

   We are lucky to see all of these cranes. In a testament to the success of federal game management, “the Rocky Mountain population reached an historic low of 150-200 breeding pairs in the 1940s (http://www.npwrc.usgs.gov/resource/birds/cranes/gruscana.htm). The current population is now estimated at 18,000 to 21,000.”
Most of Western Colorado’s cranes arrive in the fall after nesting in Alaska and the Arctic. They are looking for food and shelter for the winter and seem to be finding it. If you haven’t experienced a thousand or more cranes coming into roost, then you need to spend dusk, one evening next fall or winter, on the roads near the Escalante Wildlife Area near Delta.

   This large wintering flock near Delta is a recent phenomenon. Neither the Cornell University website (http://www.allaboutbirds.org/guide/Sandhill_Crane/lifehistory) nor the aforementioned Fish and Wildlife Service website show Sandhill Cranes wintering in Western Colorado. Our local birding bible, Birds of Western Colorado (available from Grand Valley Audubon) published in 2004, notes that since 1999, approximately 100-125 cranes have wintered in Delta. Thus, long-time local birders remember when there were few or no wintering cranes. What has changed? No one knows for sure. It could be global warming making our winters more palatable. It could also be loss of habitat elsewhere on their wintering grounds causing cranes to seek new locations.
   

    We don’t have more cranes in our area because their population has increased. The references I reviewed suggest the Rocky Mountain population may be declining slightly because of regional drought, poor survival of chicks, and increased hunting pressure.

    A significant population decline would be expensive for Colorado because Sandhill Cranes are an important economic driver. Monte Vista has a crane festival in the spring (www.cranefest.com). The Yampa Valley has one in the fall (coloradocranes.net). Right now we are amidst the Eckert Crane Days Open House (eckertcranedays.com) which features the Sandhills that frequent the area near Fruitgrower’s Reservoir.  (Here is a Western Grebe at Fruitgrower's Resevoir)

   In springtime, cranes are particularly visible and noticeable as they find thermals and spiral upward over the Grand Valley. Their call is a common harbinger of spring and recognizable by even casual observers. That call, however, is difficult to describe. According to the Cornell website, “The Sandhill Crane’s call is a loud, rolling, trumpeting sound whose unique tone is a product of anatomy: Sandhill Cranes have long tracheas (windpipes) that coil into the sternum and help the sound develop a lower pitch and harmonics that add richness….They can be heard up to 2.5 miles away and are given on the ground as well as in flight, when the flock may be very high and hard to see.” If you’ve ever strained your eyes to look up and wonder “what’s happening up there?” It was probably cranes.


    Less-known is that Sandhill Cranes nest in Western Colorado—not commonly, but there are always a few pair. They typically lay two eggs in wet, open fields such as in Unaweep Canyon. Sandhill cranes, may not reach sexual maturity until they are 7, but they pair for life, usually sustaining a two-decade or more relationship. That’s better than most human marriages. Now is a good time to celebrate “our” cranes! 

(photo by Steve Bouricius)

This post provided by Nic Korte, Grand Valley Audubon Society. Send questions/comments to audubongv@gmail.com]To learn more and to participate in the activities of Grand Valley Audubon, please see our website at audubongv.org and “like” us on Facebook!]

 

COMMENTS