In the world of retail birdhouses and feeders, the only color specifications belong to attracting specific types of birds. In fact, most birds pay little attention to the specific color of a feeder but worry more about the type of feed in the feeder or how the feeder administers feed.
Hummingbirds break those rules a bit by being attracted to brightly colored feeders, reminiscent of bright, full-of-nectar flowers. To help attract hummingbirds to nectar feeders, most commercial feeders include red parts to entice nectar-loving hummingbirds.
Color is not the only determining factor when attracting birds to feeders, so many bird watchers prefer to use clear feeders to provide easier notice that the feeder needs refilling. However, to attract birds to a new feeder, you may try wrapping parts of the feeder in reflective aluminum foil to catch birds' attention when sunlight hits the feeder.