Why are some birds drab-colored, while others are very colorful? There are many theories out there that list different reasons, but they all agree on one thing:
It's all about sex.
In most avian species, the males are more flamboyant than the females. This is simply because the female chooses her mate, not the other way around. She is looking for the most attractive male to pass on his genes. Birds are able to discern color, unlike many animals. So color can play an important role in the mating game.
In some species, both the male and female are plain brown or other drab colors. This is true mainly of birds where both sexes help care for the young. It's also in relation to the geographical location of the species.
Birds possessing the most colorful feathers are usually found in tropical rain forests or other areas that have dense foliage and offer many opportunities to hide. If, for example, you took a Bird of Paradise out of its native habitat and into an open field, it wouldn't last long. It would stand out like a sore thumb to any predators and would quickly become someone's lunch.
For this reason, many birds that live in open areas where there is a lot of brown or dull color in the area will often be similarly colored, for natural camouflage.
Colorful plumage has many meanings to other birds. It can serve as a warning to other males in the area to back off or risk a fight. It can also provide clues as to the age or status of an individual, indicating the level of his desirability as a mate.
Feather color is attributed to either pigment, which acts similar to a dye, or a different method altogether that uses light waves and how they play on the feather and create color. Examples of this latter type are peacocks, hummingbirds, some ducks, and pheasants, to name a few. The feathers are brilliantly iridescent and shimmer like jewels. Because of this, these types of feathers have always been very popular in fashion, especially for women. Depending on the light and angle, these types of feathers may even appear to change color.
Most pet birds are colorful ones. Parrots such as Macaws are well-known for brilliant plumage. Even smaller birds like parakeets or budgies, canaries, and some kinds of finches, are chosen by their owners in part, at least, because of their color or patterns. Most people looking for a pet bird wouldn't choose a dull, ordinary brown one for example- which is why you don't find them in pet shops. It may have absolutely no bearing on a bird's personality or ability to be a good pet, but people tend to want something flashy.
Birds are beautiful, fascinating creatures anyhow- and those that boast unusually colorful plumage capture our imagination and admiration in ways that few other animals can. May we ever be enchanted by them.