Sandhill cranes express their attitudes both vocally and behaviorally in a number of ways. Every posture, the color and size of their red skin patch, the way they hold their head, practically every feather, offers some kind of communication to other flock members about their intent, attitude and position within the flock.
Below you see two sandhill cranes with their skin patches showing very different attitudes. The taller or crane with his neck stretched in back, has expanded his skin patch and flushed it with blood so that it is bright red. This means he is excited, possibly alert to potential danger or responding to a nearby sandhill crane. The crane in the front has the red skin patch contracted and partially covered with gray feathers. Sandhill cranes have the ability to contract their skin patch so that less of the surface is exposed to the cold.
It's hard to imagine that sandhill cranes feeding so close together also establish territories within the feeding area. But territorial space is as important on the feeding grounds in the winter as it is during breeding season. It means the family's survival and good reproductive health in the spring. Feeding territories, of course, are much smaller and include only the space in which the crane family is currently foraging.
Sandhill cranes travel together in family groups, usually two adults with one off-spring, occasionally a family of four with two off-spring. Above you see a family of three with the mature adults on either side of a sub-adult off-spring hatched early in the season. His red facial patch is pale by comparison.
Family groups join other families to form the flocks that we see during migration. When feeding territories are being established, sometimes the whole family gets in on the dispute, usually, male sparring with male, female with female and juvenile with juvenile. At the time I was taking the next two images below, I was still in awe of the cranes approaching, and experiencing them as cautious and alert. But they were gathered here to forage and as soon as feeding began, territorial displays erupted.
Following this burst of activity, I became more alert and zoomed my 300 mm lens back to better anticipate and capture these disputes!
Below, you see a sandhill crane walking with his head down showing a bright red skin patch engorged with blood. This head position is a mild threat posture as the crane moves into an area where other cranes are feeding. He also is displaying "plume" feathers, which are actually the raised tertiary wing feathers.
Below, two juveniles have a dispute over their feeding territory (note the cinnamon on the back of the jumping cranes's head). The crane on the right is in the midst of a "jump rake", one of the more aggressive behavioral displays in which the crane jumps and rakes the air with his claws.
The opposing juvenile responds with a similar jump. Especially notice below, how the adults in the families are joining in the dispute vocally. If the dispute does not settle quickly, they will join the juveniles in displaying to each other.
Mostly, territorial disputes include vocals and behavioral displays without physical contact. Disputes settle quickly and the cranes go back to foraging peacefully, which is the whole purpose of their flocking together in feeding areas. The flock serves the sandhill cranes' survival by aiding in the location of food sources and by providing many eyes on the alert for danger.
I love observing behavior. In the past, I have spent many hours watching herd behavior in horses, noticing how this "prey" species communicates with the most subtle of movements and gestures, creating heirarchy within the herd and a fine-tuned response to danger. Having an opportunity to watch sandhill cranes create this same kind of order with feathers, vocals, and posturing is priceless to me, and especially gratifying knowing that Hiwassee's sandhill cranes, the Eastern Population of Greater Sandhill Cranes, was once on the brink of extinction.
Next post: Displays, vocals, and a late season juvenile.
Links and Resources:
To see the first post in this three-part series visit: An Intimate Visit with Hiwassee's Sandhill Cranes
Top Crane Posts on this blog: Hooded Crane at the Hiwassee Wildlife Refuge in TN
Sandhill crane art in my website galleries