Cases of leucism have been reported in Nebraska birds at each end of state over the past few weeks. Before taking cover in your bunker with concerns about the next avian-related pandemic, it might be useful to define leucism. Leucism is a type of abnormal coloration in a bird’s plumage. Specifically, it is variable amounts of either white or pale coloration in feathers that typically have pigment. Even though leucism is rare, it is regularly observed. I receive a few photos each year of leucistic birds with questions from the observer about identification. The most recent were photos from Robert Sanford of this leucistic Common Grackle observed in Lincoln over the weekend.
Leucism is reported regularly in blackbirds, which is the family which Common Grackles belong. Leucistic Red-tailed Hawks are occasionally reported and I also receive a report or two of leucistic American Robins each year, some of which appear “frosted” and are quite beautiful. The one pictured below, which was apparently part of a small band of leucistic American Robins, was recently observed by Dick and Karen Broderick in Alliance.
While reports of leucism are often common backyard species, it can be expected to occur on occasion in other less familiar birds as well. Below, is a photo of a leucistic Green-winged Teal from the Rainwater Basin from a few years ago.
Pictured below is a leucistic Baird’s Sandpiper. Baird’s Sandpiper’s head and upper breast are usually brown. Unfortunately, leucistic birds often do not cooperate for nice photos.
Finally, here is a nice video from YouTube showing a leucistic individual of the familiar Black-capped Chickadee (location unknown).[youtube]http://www.youtube.com/watch?v=NnqiXI4O0ro[/youtube]
Leucism is an interesting term that has undergone some evolution. One key point is leucism can by synonymous with partial albinism (= albino) and some authors may distinguish between partial leucism and complete leucism (see the link at the end of this post). However, leucism is different than pure albinism, which is a genetic mutation that results in the complete lack of all pigment. Remember that key point the next time you want to be the smartest person in the room at a cocktail party. If you are interested in additional information regarding abnormal bird plumages, including leucism and albinism, check out David Sibley’s thorough and useful discussion here.