Burns, K. C. (Bamfield Marine Science Centre, 1 Pachina Drive, Bamfield, British Columbia, Canada, V0R 1B0). Effects of bi-colored displays on avian fruit color preferences in a color polymorphic plant. J. Torrey Bot. Soc. 132: 505–509. 2005.—Rubus spectabilis is a bird-dispersed shrub that produces both red and orange fruits. Although it has been the subject of several previous studies, the factors responsible for the maintenance of the polymorphism have not been identified. I hypothesized that the fruit color polymorphism in R. spectabilis is maintained by enhanced conspicuousness of bi-colored displays, created when the two color forms occur close together. To test this hypothesis, I constructed experimental displays of different relative abundances of red and orange fruits and presented them to free-ranging birds in British Columbia, Canada. Trials were conducted in different habitats and at different times during the fruiting season to test whether avian fruit color preferences were spatially or temporally variable. Results showed that birds did not prefer bi-colored displays and that removal rates of different colored fruits were similar in space and time. Therefore, processes other than enhanced conspicuousness of bi-colored displays must account for the maintenance of the fruit color polymorphism.