Leucism in birds is caused by a defect in pigment cells during development. Recently, we were fortunate to photograph a Red-tailed Hawk that is considered leucistic. This causes some or all of the feathers to be white, but the rest of the bird to be normal in coloration. A leucistic bird has the normal amount of melanin, but the pigments failed to be deposited normally in the feathers during development. Leucistic birds are often more susceptible to predation and feather deterioration. Melanin provides strength and is an important structural component of feathers. Lack of melanin causes feathers to wear down faster. Leucistic birds may also have a harder time finding a suitable mate. The Cornell Lab of Ornithology, in its annual Project Feeder Watch from the years 2000 to 2006, found fewer than 1,000 leucistic birds recorded among about 30 million birds reported over those years.
As we approach spring migration, be sure to stop and watch our avian friends. You never know when you might be surprised by a bird with some unusual plumage.
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