Pale Beauty - why so pale?

Pale Beauty on the snow 2/11/11
photo courtesy of PaleMale.com

Yesterday John Blakeman wrote:

Marie,

It now clear that Pale Beauty is leucistic. [note from Marie: Leucism is a condition that affects birds' feathers and turns them pale or white.]

.

Palemale.com’s recent photos of her show two such traits. First, the shafts of her central tail feathers are decidedly whitish, along with weak pigmentation in much of the rest of those feathers.

But more importantly, she has an almost pure white (and a bit foreshortened) outer left tail feather. This is markedly leucistic.

As she ages, in the coming years, I will expect more and more primary wing and tail feathers to molt out white. In a few years, she might be almost entirely white.

There is now no doubt that she has leucistic genes.

–John Blakeman

A second note from Blakeman followed:

Marie,

More comments on Pale Beauty’s tail feathers and their coloration.

A center tail feather is stubbed off, having lost most of its length from an injury. Pale Male lost the tips of his fourth and fifth primaries of his left wing. Pale Beauty lost most of the length of a central tail feather. The pair shares some feather injuries.

Secondly, two of the tail feathers, including the one adjacent to the left, outermost white feather, lack the normal dark sub-terminal bands. This anomaly is yet another indication of leucistic genes. The lack of a sub-terminal band is seen in a small fraction of Red-tailed Hawks, but it normally occurs in all the tail feathers. In those cases, there is no association with leucisticism. Not so in Pale Beauty’s case. She’s lacking the band in only three feathers, the white one and two red ones. This non-unilaterality or pattern unevenness is another trait of Red-tail leucisticism.

As I mentioned previously, all of this indicates a strong chance that each ensuing annual molt will exhibit increasing numbers of white feathers. In a few years, we could have an angelic white Red-tail gracing the skies of Central Park. I have seen these birds in the wild, and trapped and studied one. They are profoundly majestic. "Pale Beauty" is now even more applicable.

I've attached a photo of a leucistic Red-tail that had been injurred and was in the care of an Ohio raptor rehabilitaion facility.

–John Blakeman