It is that time of year! The majestic Sandhill Cranes visit Monte Vista National Wildlife Refuge in San Luis Valley, Colorado–and so do we. Thousands of cranes rest at the Refuge each spring in preparation for their flight to nesting grounds in northern US and Canada. What a sight!
The most active times of day are about 45 minutes on either side of both sunrise and sunset. Cranes roost in shallow water overnight in large flocks which protects them from predators. As morning light begins, the cranes begin heading for daytime loafing areas where they feed on the remaining seeds from last fall’s harvest on area farmlands as well as invertebrates and small vertebrates in wetlands. Resting and feeding for a week or more in preparation for the next stage of their journey north to nest.
Cranes have a wide range of social body language, their dancing is probably best known. We saw some great dancing last year. Now let’s take a look at some of their other interesting body language.
See the cranes reaching their necks forward? That is intent-to-fly language. Their necks get straighter and straighter, pointing in the direction they intend to fly, and all those intending to join them display the same posture. Sure enough, a few minutes later the three cranes took off.
This is a dancing pair. Leaping in the air with wings spread, called dancing, can mean a pair is re-establishing their bond. Cranes choose mates between two- and five-years old, and mate for life. Sandhill Cranes live between 30 and 35 years.
But of course it isn’t that simple. Dancing is a primary part of the cranes behavior. Parents dance with their young, teaching the basics. Pre-adult cranes practice dancing for years before selecting a mate. So what is going on here? Often a mated pair’s male will leap and jump as the female tilts forward, as the bird on the left with bill open. Cranes often dance as play, but can be combined with other movements to express dominance among its peers. This looks like it may be a dominance display.
This is the male’s body position for crane calls, the stance of a male/female unison call are different. Cranes call to maintain contact with their mate or monitor locations of their crane neighbors. Apparently it isn’t usual for two males to issue a call together like this, but perhaps they are just showing off.
Cranes ruffle their feathers to get rid of dust–and there is a lot of dust in Colorado–and feather dander. But it can also mean there’s a threat if the ruffling includes gyrations, like the middle crane, and expanded crown, which none of them are displaying. What does “expanded crown” mean? Glad you asked!
The crown is the top of the head, but what is expanded is the red skin. Yes, it is red skin rather than feathers. I wish I had been able to get this close. See caption.
The contracted crown is a sign that the crane is relaxed and not stressed.
This is an expanded crown. The red skin is pulled back over the head. It signals arousal or excitement. Also note the “bustle” that looks like a tail. It is not the tail but the edges of the wing’s flight feathers which covers a rather small tail. The raised bustle is also a sign of arousal.
There are three subspecies of Sandhill Cranes that visit the Refuge. The Greater, Lesser, and Canadian, and happily the Greater Sandhills have made a significant comeback since the mid-20th century. All three look nearly identical except for their size. The Greater is the largest, hence the name, and the Lesser is 50% smaller. The Canadian is between the two making them nearly impossible to identify.
There are a few ID cues that can help separate the Lesser and Greater. Lessers have shorter bills and smaller heads with less red bare skin. Also, the white cheek patch contrasts much less on the Lesser than the Greater. The picture above is a Greater. Can you see the difference looking at the Lessers below?
I know, hard to tell. It is easy to think the smaller cranes are just “juvenile” Greater Sandhills, but the juvenile cranes are full grown between five and six months old. By the time they migrate south for the first time next fall, they will be the size of their parents. The Lesser’s size when next to a Greater makes an ID much easier. Can you tell the difference now?
The Lesser pair that shared some time with us.
As daylight wanes the cranes begin returning to the nighttime safety of the lake’s shallows here and other lakes across the valley.
What a marvelous day with the cranes! Did you know they are among the oldest living birds on the planet? Cranes have fossil records dating back nine-million years. Between 20-25,000 cranes migrate through this valley and make up the Rocky Mountain Population (RMP). They breed in Idaho, Utah, western Montana and Wyoming which makes up the Greater Yellowstone Ecosystem, my old stomping grounds. They winter in New Mexico and northern Mexico.
You may have heard of the cranes migrating through Nebraska which are the Mid-Continent Population (MCP) and the largest group in North American. The migration stopover is the Platte River Valley and as many as 600,000 cranes grace the skies. These cranes breed in northwest Minnesota, western Quebec, and northwest through Canada, Alaska, and Siberia. They winter in Oklahoma, New Mexico, Arizona, Texas, and Mexico. Come explore the southwest in winter, especially New Mexico, and visit with cranes!
As the sun sets, we have glorious evening skies. We will end where we began this morning, enjoying the Mt. Blanca range to the east, still hearing the cranes calling in the dark.
Until next time my friend . . .
