I have noticed a leucistic hummingbird at my feeder on occasion. Today, it appeared, and I was only able to grab a couple of photos through the window, at higher ISO and into shadow - a very much less than ideal situation. I believe it is a female Costa's. I have normal plumage male and female Costa's, Broad-billed, and Anna's, so I've been able to compare the features. This one is not albino because it has color in its eyes, bill, and feet, and just a slight wash of pinkish coloration. I will keep trying for a better shot! Taken with Canon 40D and 300mm f/4 L IS +1.4x.