QuestionSandhill crane
Why Are Some Sandhill Cranes Brown? Feather Painting Explained
Some sandhill cranes are brown because they paint themselves. Adult sandhill cranes have gray feathers, but in spring and summer many preen iron-rich mud into their plumage, staining it a rusty or ochre brown. Scientists think this helps the birds blend into brown marsh vegetation while they are nesting.
Contents
Gray birds with a rusty coat
A clean adult sandhill crane is soft gray with whitish cheeks and a bright red crown. Yet photos taken in spring and summer often show birds that look brown, cinnamon or even orange on the back, wings and neck. The color is uneven: it may be patchy, darkest on the back and wing coverts, and the head and neck often stay grayer.
The difference is not genetic and does not mark a separate subspecies. Two gray cranes standing side by side can look completely different if one has been painting and the other has not.
How sandhill cranes paint their feathers
Sandhill cranes do the painting themselves while preening. A crane probes into wet soil, mud or decaying plant material with its bill, then rubs the mud over its feathers, working it in with the same motions it uses to clean and arrange them. The process is repeated many times.
The rusty color comes mainly from iron oxides in the soil, the same compounds that give rust and red clay their color. Where the local mud is rich in iron, painted cranes turn deep rusty brown. Where the soil contains less iron, the stain is paler or barely visible. This is one reason why the amount of brown differs between populations and places.
Painting is especially common in migratory populations that nest in northern marshes and bogs. Resident cranes in Florida can also show it, but many stay noticeably grayer.
Why do sandhill cranes paint themselves?
The most widely accepted explanation is camouflage while nesting. A sandhill crane nests on the ground or in shallow water, on a low mound of plant material. An incubating bird sits on its eggs for about 30 days, with partners taking turns. A pale gray body stands out against brown cattails, sedges and dead grass in spring; a mud-stained one is much harder for coyotes, foxes, ravens and other predators to spot.
Several observations support this idea:
- Painting is concentrated in the breeding season, from spring into summer.
- The stained areas, the back and wings, are the parts most visible on a sitting bird.
- Cranes often paint after arriving at breeding sites, when the vegetation around them is still brown.
Scientists have suggested other possible benefits, such as discouraging feather parasites, but these have not been well tested. Camouflage remains the leading explanation.
When does the brown color fade?
The stain does not last forever. It wears gradually and disappears when cranes replace their body feathers during molt, mainly after the breeding season in late summer and fall. By late fall and winter, many sandhill cranes on migration or in their wintering grounds look gray again, until they start painting the next spring.
This seasonal cycle is useful to know if you watch cranes. A mixed flock at a stopover may include clean gray adults, rusty-stained adults and cinnamon-brown juveniles all at once.
Brown juveniles vs painted adults
| Feature | Painted adult | Juvenile (colt) |
|---|---|---|
| Body color | Gray with uneven rusty staining | Even cinnamon or tawny brown |
| Crown | Bright red bare skin | Feathered, no red patch |
| Head | Whitish cheeks | Brownish head |
| When seen | Mainly spring and summer | Summer through the first winter |
Juvenile cranes gain the red crown and gray adult plumage during their second year.
Other birds that paint themselves
Sandhill cranes are not the only birds that change their color with cosmetics:
- Common crane: the Eurasian relative of the sandhill crane also daubs mud on its back during the breeding season, apparently for the same camouflage reason.
- Bearded vulture: this Old World vulture bathes in iron-oxide-rich soil or water, which stains its naturally white underparts rusty orange. The purpose is still debated; ideas include signaling status.
- Flamingos: greater flamingos rub carotenoid-rich oil from their preen gland onto their feathers, making their plumage look pinker during courtship. Find out more in why flamingos are pink.
These examples show that a bird’s color is not always fixed by its genes. Some birds actively manage how they look.
Myths about brown sandhill cranes
Myth: Brown sandhill cranes are a different species or a hybrid. They are ordinary sandhill cranes with stained feathers.
Myth: Brown birds are always young. Juveniles are brown, but most brown cranes seen in spring and summer are painted adults with a red crown.
Myth: Cranes are stained by accident when they feed in mud. Some staining may happen while feeding, but cranes are regularly seen applying mud deliberately while preening. To learn more about crane behavior, see why cranes dance.
Frequently asked questions
What color are sandhill cranes naturally?
Adult sandhill cranes are naturally gray, with whitish cheeks and a red patch of bare skin on the crown. The brown color many birds show is a stain, not their true feather color.
Are brown sandhill cranes juveniles?
Some are. Young cranes are cinnamon brown and lack the red crown. But many brown cranes are adults that have stained their gray feathers with mud; they still have the bright red crown.
Do sandhill cranes paint their feathers on purpose?
They apply the mud deliberately with their bills while preening, mainly in spring and summer. The most widely accepted explanation is camouflage, though scientists have not tested every possible reason.
When do sandhill cranes turn gray again?
The stain wears off gradually and disappears when the cranes molt and grow fresh body feathers, mostly after the breeding season. By late fall and winter many cranes look gray again.
Do other birds paint their feathers?
Yes. The Eurasian common crane also daubs mud on its plumage, the bearded vulture stains itself orange with iron-rich soil, and flamingos rub pink pigment from their preen gland onto their feathers.
Sources and further reading
- Cornell Lab of Ornithology, All About Birds, "Sandhill Crane"
- Animal Diversity Web (University of Michigan), "Grus canadensis"
- Johnsgard, P. A., Cranes of the World (1983)
Cite this page
“Why Are Some Sandhill Cranes Brown? Feather Painting Explained.” Animal Atlas, https://animals.bigworldlist.com/questions/why-are-sandhill-cranes-brown/.
