Usually bluebirds (Sialia spp.) lay unmarked light blue eggs (Bent 1949). Albinistic eggs have been reported for all three North American species (Musselman 1935, Laskey 1939, Power 1966, Eltzroth 1983), but are considered unusual. The fertility of albinistic eggs has been confirmed for the Eastern Bluebird (S. sialis; Musselman 1935, Laskey 1939) and the Mountain Bluebird (S. currucoides; Power 1966, Munro et al. 1981) but not the Western Bluebird (S. mexicana).