Sandhill Crane

The **sandhill crane** (*Antigone canadensis*) is a species of large crane of North America and extreme northeastern Siberia. The common name of this bird refers to habitat like that at the Platte River, on the edge of Nebraska's Sandhills on the American Plains. This is the most important stopover area for the nominotypical subspecies, the **lesser sandhill crane** (*Antigone canadensis canadensis*), with up to 450,000 of these birds migrating through annually.

The sandhill crane was formerly placed in the genus *Grus*, but a molecular phylogenetic study published in 2010 found that the genus, as then defined, was polyphyletic. In the resulting rearrangement to create monophyletic genera, four species, including the sandhill crane, were placed in the resurrected genus *Antigone* that had originally been erected by the German naturalist Ludwig Reichenbach in 1853. The specific epithet *canadensis* is the modern Latin word for "Canadian".

## Description

Adults are gray overall; during breeding, their plumage is usually much worn and stained, particularly in the migratory populations, and looks nearly ochre. The average weight of the larger males is 4.57 kg (10.1 lb), while the average weight of females is 4.02 kg (8.9 lb), with a range of 2.7 to 6.7 kg (6.0 to 14.8 lb) across the subspecies. Sandhill cranes have red foreheads, white cheeks, and long, dark, pointed bills. In flight, their long, dark legs trail behind, and their long necks keep straight. Immature birds have reddish-brown upperparts and gray underparts. The sexes look alike. Sizes vary among the different subspecies; the average height of these birds is around 80 to 136 cm (2 ft 7 in to 4 ft 6 in). Their wing chords are typically 41.8–60 cm (16.5–23.6 in), tails are 10–26.4 cm (3.9–10.4 in), the exposed culmens are 6.9–16 cm (2.7–6.3 in) long, and the tarsi measure 15.5–26.6 cm (6.1–10.5 in).

These cranes frequently give a loud, trumpeting call that suggests a rolled "r" in the throat, and they can be heard from a long distance. Mated pairs of cranes engage in "unison calling". The cranes stand close together, calling in a synchronized and complex duet. The female makes two calls for every one from the male.

Sandhill cranes' large wingspans, typically 1.65 to 2.30 m (5 ft 5 in to 7 ft 7 in), make them very skilled soaring birds, similar in style to hawks and eagles. Using thermals to obtain lift, they can stay aloft for many hours, requiring only occasional flapping of their wings, thus expending little energy. Migratory flocks contain hundreds of birds, and can create clear outlines of the normally invisible rising columns of air (thermals) they ride.

Sandhill cranes fly south for the winter. In their wintering areas, they form flocks over 10,000. One place this happens is at Bosque del Apache National Wildlife Refuge, 100 mi (160 km) south of Albuquerque, New Mexico. An annual Sandhill Crane Festival is held there in November.

## Behavior

A huge flock at Bosque del Apache National Wildlife Refuge, New Mexico

Sandhill cranes are fairly social birds that usually live in pairs or family groups through the year. During migration and winter, unrelated cranes come together to form "survival groups" that forage and roost together. Such groups often congregate at migration and winter sites, sometimes in the thousands.

### Eggs

Usually 2, sometimes 1, rarely 3. Variably pale olive to buff, marked with brown or gray. Incubation is by both sexes, 29-32 days. Female does more of incubating (typically all night, part of day). Young: Leave the nest within a day after hatching, follow parents in marsh. Both parents feed young at first, but young gradually learn to feed themselves. Age at first flight about 65-75 days. Young remain with parents for 9-10 months, accompanying them in migration.

### Young

Leave the nest within a day after hatching, follow parents in marsh. Both parents feed young at first, but young gradually learn to feed themselves. Age at first flight about 65-75 days. Young remain with parents for 9-10 months, accompanying them in migration.

### Diet

Omnivorous. Diet varies widely with location and season. Major food items include insects, roots of aquatic plants; also eat rodents, snails, frogs, lizards, snakes, nestling birds, berries, seeds. May eat large quantities of cultivated grains when available.

### Nesting

Courtship includes elaborate "dance," with birds spreading wings, leaping in air while calling. Nest site is among marsh vegetation in shallow water (sometimes up to 3' deep), sometimes on dry ground close to water. Nest (built by both sexes) is mound of plant material pulled up from around site; nest may be built up from bottom or may be floating, anchored to standing plants.

## Diet

Sandhill cranes are mainly herbivorous, but eat various types of food, depending on availability. They often feed with their bills down to the ground as they root around for seeds and other foods, in shallow wetlands with vegetation or various upland habitats. Cranes readily eat cultivated foods such as corn, wheat, cottonseed, and sorghum. Waste corn is useful to cranes preparing for migration, providing them with nutrients for the long journey. Among northern races of sandhill cranes, the diet is most varied, especially among breeding birds. They variously feed on berries, small mammals, insects, snails, reptiles, and amphibians.

## Predators and Self-Defense

As a conspicuous ground-dwelling species, sandhill cranes are at risk from predators, which are probably the main nonanthropogenic source of mortality. Mammals such as foxes, raccoons, coyotes, wolves, cougars, bobcats, and lynx hunt them given any opportunity, the first three mainly hunting large numbers of young cranes, the latter four types more rarely taking full-grown cranes in ambush excepting the prolific bobcat. Corvids, such as ravens and crows, gulls, and smaller raptors such as hawks (largely northern harriers or red-tailed hawk) feed on young cranes and eggs. Cranes of all ages are hunted by both North American species of eagles. Mainly chicks and possibly a few adults may be preyed on by great horned owl and even the much smaller peregrine falcons has successfully killed a 3.1 kg (6.8 lb) adult sandhill crane in a stoop. In Oregon and California, the most serious predators of flighted juveniles and adults has been cited as golden eagles and bobcats, the most serious predators of chicks are reportedly coyotes, ravens, raccoons, American mink, and great horned owls in rough descending order. In Cuba and Florida, the American crocodile and alligator can take a surprisingly large number of sandhill cranes, especially recent fledglings. Sandhill cranes defend themselves and their young from aerial predators by jumping and kicking. Actively brooding adults are more likely to react aggressively to potential predators to defend their chicks than wintering birds, which most often normally try to evade attacks on foot or in flight. For land predators, they move forward, often hissing, with their wings open and bills pointed. If the predator persists, the crane stabs with its bill (which is powerful enough to pierce the skull of a small carnivore) and kicks.