Crane Signal Dictionary: Part 3. Attack & defense

See also Part 1: Social body language and Part 2: Dance steps.

Physical contact and outright attack between adult cranes is largely avoided because of the refined social body language between neighbors that keeps cranes out of each other's personal space. As cranes become emotionally aroused, social or dance displays (Bow, Gape, Run-flap, Jump-rake) may "spill over" into threat that can culminate in attack.

The leaping and jumping of attacking cranes is spectacular. Argumentative agonistic pre-attack displays can escalate into spirited fights over territory, food sources, or mates, and potential predators are expelled with gusto.

Any description of crane displays must pay tribute to the pioneering study based on meticulous observations of Japanese crane behavior by Masatomi and Kitagawa (cited below).An excellent Field Guide to Crane Behavior can be downloaded as a pdf from the International Crane Foundation. For our dictionary of crane body language, we are especially indebted to the "Sociogram" of Ellis and colleagues and also to others referenced below.

We welcome emails that suggest improvements/corrections/additions for this dictionary.

Links to display images & descriptions:

Bill-spar

Bill SparColt Bill-spar

The cranes stand tall, face-to-face, vocalizing and stabbing toward each other. The display may escalate into mutual Jump-rakes, with feet tearing at the opposing crane.

Bill-sparring may be used for the establishment of a dominance hierarchy in small flocks (Kepler 1975 cited in Nesbitt and Archibald5). It is frequently seen between twin colts on staging areas and even on nesting territories as early as 4 days of age (right image).

Cower

CowerCower

The crane walks or stands with neck curved down, head held low and retracted, and often with feathers of the head and neck fluffed. In the extreme form of Cower, the crane lowers back on its heels to a sit or lie position.

A defensive display characteristic of very submissive young and ill cranes. Drawing from Ellis2.

Bill-down

Bill Down Display

The head is lowered until the bill touches or nearly touches the ground and the posture is held for several seconds. The bare skin is expanded and tertiary feathers raised.
Eliis and colleagues report that cranes emit a growl/purr during this threat display.

Running-charge-threat

running charge

Running forward, wings flapping, with stabbing posture. In this case, the intruder was a mallard duck, a competitor for food.

Crouch-threat

Crouch-threat

The crane, with bare skin expanded. lowers briefly to the lie position, sleeks the neck feathers, partially spreads the drooping wings as they touch the ground, and pecks/nibbles/tugs at vegetation.

This displaying bird is an adult female, banded in 2006 at Creamers Refuge (a staging area in Fairbanks, AK) and photographed in 2009 at Creamers. Just before the Crouch-threat, two crane pairs, standing close together, emitted unison-calls and then the female dropped into the display.

The quick display appers to be a high arousal version of Stab-tug-nibble that often leads to direct attack.

Bill-stab

Bill-stab

 

Roy and Millie are shielding twin colts from an attacking Mew Gull. Roy (left) peers up at his target with wings partly spread, wrists held out and neck thrust forward. Millie (right) is partially crouched, with neck coiled tightly back, poised to stab.

The stab can be deadly. Bent1 reports: 1) a Bill-stab by a wounded whooping crane skewered and killed a small dog and 2) a wounded whooping crane stabbed a hunter in the eye, resulting in his death.

References

1. Bent AC, 1926. Life histories of North American marsh birds. Orders Odontoglossae, Herodiones and Paludicolae. U.S. Natl. Mus. Bull. 135, p. 227.

2. Ellis DH, Swengel SR, Archibald GE, Kepler CB 1998 A sociogram for cranes of the world. Behavioral Processes 43:125-151.

3. Johnsgard P 1983. Cranes of the World. 2. Individualistic and social behavior. Papers in Biological Sciences, University of Nebraska, Lincoln, pp. 11-24.

4. Masatomi H, Kitagawa T 1975. Bionomics and sociology of the Japanese Crane, Grus japoniensis, II. Ethogram. Jour. Fac. Sci. Hokkaido Univ. Ser. VI, Zool. 19:834-878.

5. Nesbitt SA, Archibald GW 1981. The agonistic repertoire of sandhill cranes. Wilson Bulletin 93:99-103.

6. Tacha T 1988. Social organization of the cranes from midcontinetal North America. Wildl. Monogr. 99:1-37.

7. Voss KH 1977. Agonistic behavior of the Greater Sandhill Crane. Eastern Greater Sandhill Crane Symposium, pp. 63-85.

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