William E. Davis, Jr.
Figure 1 (left). The crown is white except for a few streaks of brown toward the rear.
Figure 2 (right). Front view of the leucistic House Sparrow. Photographs by the author.
On August 31, 2018, I noticed a male House Sparrow (Passer domesticus) at my bird feeders in East Falmouth, Massachusetts, that had an all white crown rather than the typical dark gray. This bird was part of a flock of more than a dozen House Sparrows that frequented my feeders; I saw the bird again at my feeders on September 9–16. I photographed the bird and carefully examined it through binoculars. The feathering appeared to be normal except for the crown, which was pure white with the exception of several small streaks of brown toward the back (Figures 1 and 2). The eye color was normal. The cheeks appeared to be off-white in the photographs (Figures 3 and 4) but close examination through binoculars showed them to be a silvery light gray, which is normal coloration for male House Sparrows in fall.
People might describe this House Sparrow as a "partial albino," but the correct term is "leucino." True albinos, in contrast to this bird, lack all pigmentation resulting in completely white feathers, as well as pink eyes, beaks, legs, and feet (Buckley 1982). Leucinos lack a particular pigment, such as melanin, or pigments, in the feathers but not in the soft parts and the loss of pigmentation may be complete or partial. An all white bird with a dark eye and normal bill coloration would be a leucino, not an albino. The white on the crown of this House Sparrow was symmetrical so it could be referred to as a symmetrical partial non-melanic leucino.
Leucism, although rare in birds, is much more common than albinism and is found in a broad spectrum of bird families and species. For example, a review of the Australian literature by Lepschi (1990) found albino or leucistic birds reported in 95 species of 45 families. Ross (1963) found nearly 500 "albino" bird specimens in U.S. museums and literature (albino here included leucistic birds because you can't check eye color in museum specimens and the terms albino and leucino are frequently confused in the literature). I have previously reported on leucism in an American Goldfinch (1990), Northern Mockingbird (1995), Australian Magpie (Davis and Recher1996), and Boat-tailed Grackle (2015). Although true albino birds are at a disadvantage because the lack of pigment deleteriously affects their eyesight, leucino birds appear capable of leading somewhat normal lives: the mockingbird mentioned above attracted a mate and raised a brood of four, the magpie had been seen in the same field for more than a year, and the Boat-tailed Grackle had been observed in the same location for several years. I have closely observed the leucino House Sparrow and found that its behavior and interactions within the flock appear normal.
I checked the internet for references and pictures of albino and leucino House Sparrows and found more than a dozen examples of leucism, including birds with all white feathers but dark eyes, a bird with mostly white primaries, and birds with a patchy distribution of white. Only two photographs were of albinos, although several of the leucistic birds were referred to as albinos. Interestingly, I found one reference and photograph by Lillian Stokes in which a female House Sparrow in Georgia had a white crown and was otherwise normally plumaged, apparently the female counterpart of my male bird (stokesbirdingblog.blogspot.com/2010/10/white-headed-junco-speckled-robin-what.html).
Literature cited
- Buckley, P. A. 1982. Avian Genetics. Second Edition. Pp. 21-110 in M. L. Petrak, ed., Diseases of Cage and Aviary Birds. Second edition. Philadelphia: Lea and Febiger.
- Davis, W. E., Jr. 1990. Two Aberrant Goldfinches. Bird Observer 18: 335–339.
- Davis, W. E., Jr. 1995. An Aberrant Mockingbird. Bird Observer 23: 161–164.
- Davis, W. E., Jr., and H. F. Recher. 1996. A Leucistic Australian Magpie Gymnorhina tibicen dorsalis in Western Australia. Australian Bird Watcher 16: 303–304.
- Davis, W. E., Jr. 2015. Leucistic Female Boat-tailed Grackle. Bird Observer 43: 388–389.
- Lepschi, B. J. 1990. The Incidence of Albinism and Melanism in Australian Birds: A Review of the Literature. Corella 14: 82–85.
- Ross, C. C. 1963. Albinism among North American Birds. Cassinia 47: 2–21.