by Djop Tabaranza
Among the representatives of the animal kingdom, birds are the only group which have feathers. Feathers are specialized skin covers that are collectively known as “plumage.” The term “plumage” was derived from the Latin “pluma” which means feathers and refers to the bird’s collective feather covering, including its colors and patterns.
During birdwatching trips, you may have heard the more experienced birders mention the terms like “juvenile,” “immature,” “sub-adult” or “adult.” These terms refer to the age of the birds based on their plumage. Young birds pass through one or more plumage before they reach the final or full adult plumage. Some literature suggests that “juvenile plumage” refers to a bird’s first plumage after it sheds its downy feathers while “immature plumage” refers to any plumage between the juvenile and adult plumage.
Here are some examples of birds showing different plumage.
Below are Asian Glossy Starlings in their streaked immature (left) and glossy black adult (right) plumage.
Aside from “age”, some species exhibit different plumage depending on the season. Notably, the difference between the drab non-breeding or winter plumage and the more vibrant breeding plumage which they use to attract mates. Featured below are Javan Pond-herons exhibiting breeding (left) and non-breeding (right) plumage.
More often, males exhibit the more brilliant plumage for courtship whereas females have duller coloration to attract less attention to themselves especially as they tend to their nest and chicks. This “sexual dimorphism,” or the difference between males and females of the same species, is exhibited by the Olive-backed Sunbirds and the Philippine Green Pigeons below.
However in some species, the female would have the more brilliant plumage over the duller colored male as shown below by Greater Painted Snipes.
Next time you are out birding, try to look out for these plumage variations try to guess which are the juveniles, immature, adult, male and female. It may seem confusing and a bit overwhelming at first, but the more you go out and bird, the more familiar you will get with the different plumage of birds.