Dear Ray,
Count yourself lucky - you've seen something very rare. When a grackle has one or more white feathers, the most likely couse is leucism, or partial albinism. Leucism affects about 1 in 30,000 birds.
In the past I have explained how a natural pigment called melanin (the same one that humans have in ther skin) lends grackles our glossy black feathers. In leucistic birds, the affected feathers lack the cells responsible for produciing melanin, and so the feathers grow out white. Leucism is genetic, but can also be influenced by injury or environmental conditions. For example, in the aftermath of chernobyl, researchers documented a tenfold increase of leucisim (and albinism) in barn swallows.
There are a few other reasons grackle's plumage could look different than normal, including genetic conditions, age and nutrition, but the white tail feathers, you're describing sounds like leucism to me.
I've seen a couple of leucistic grackles in my day, and i'm always a bit jealous -the black and white colors look so sharp together. I've seen humans try to capture this look when they're dressing up in tuxedos, but in my opinion, those rare leucistic grackles will always wear it better!
Yours,
Grackle
Have a question for the grackle? Email us at magazine@tpwd.texas.gov and we will pass it along to our avian adviser. The grackle's opinions are its own and do not necessarily reflect the views of the Texas Parks and Wildlife Department.
