The bird that dyes its feathers

Many birds molt feathers twice a year, before the breeding season (and spring migration) to enhance their sex appeal and gain maximum aerodynamic efficiency, and again after the breeding season is concluded, to become more cryptic and less vulnerable to predation.

Sandhill Cranes have a different strategy; they take a mud bath by preening iron-rich mud into their breast and back feathers during the breeding season, in order to become the “little brown crane” of the early ornithology literature.  At the end of the breeding season this coat of brown feathers is shed as new gray body and wing feathers are molted.

The difference in their coloration from fall to spring is striking.

A pari of Sandhill Cranes in their recently molted fall plumage, with gray plumage and red crown feathers.

A pair of Sandhill Cranes in their recently molted fall plumage, with gray plumage and red crown feathers.  These cranes were easy to spot in the field of drying grass and cattails last October.

A  pair off Sandhill Cranes looking fine in their mud-dyed spring plumage.

A pair off Sandhill Cranes looking fine in their mud-dyed spring plumage.  The heads are still gray but the neck, breast and back feathers have taken on a russet hue, and now they are quite difficult to see in among the dead cattail stems.  Taken at Sherburne National Wildlife Refuge May 18, 2014.

Apparently cranes love mud, and will immediately start mud-preening when presented with a suitable substrate — even if it is from a bucket of mud placed in their zoo crane pen!

Is this an attempt by the cranes to become more cryptic at a vulnerable time in their life cycle — while they are incubating and molting flight feathers?

A nesting sandhill crane was still obvious as a brown lump in an otherwise straw colored background.

A nesting Sandhill Crane at Sherburne NWR  today was still obvious as a brown lump in an otherwise straw colored background.

Still obvious from another perspective...

Still obvious from another perspective…although perhaps we had the advantage of bright daylight and height above the nesting bird.

Or is the feather dyeing behavior an attempt to rid the bird of irritating feather parasites? Many birds take “dust baths” to suffocate those little pests in their feathers which they then preen out.  And what is the significance of preening themselves with iron-rich mud; does iron retard ectoparasite activity?

Here’s what D.O. Hyde had to say about this in 1968:  Adult cranes stain their plumage “as an intentional desire to change the color of the feathers associated with the act of pairing or connubial bliss”.

Nah….I’m not in favor of that explanation.  What about you?

8 thoughts on “The bird that dyes its feathers

    • Makes for good humor though. You have to wonder about the state of published science back in the 1960s, which to me, isn’t all that long ago!

  1. That is fascinating. I too am unconvinced by the 1960s theory. But then I am unconvinced by lots of things that came out of that crazy, but sometimes brilliant decade. Your pictures are super and really illustrate the natural history.

    • Yes, well, it bothered me that the birds that were supposed to be gray were all brown. You know the old saying, “inquiring minds want to know…”

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