The wings of a bird and the wings of an insect are:

The structures in different organisms which are not similar anatomically though they perform similar functions are called as analogous organs. Morphologically they may or may not be similar which means that analogous structures may or may not look alike externally. The property of bearing analogous structures is called analogy. The analogous structures do not exhibit common origin. Unlike homology which indicates common ancestry, the analogy does not indicate common ancestry.

The wings of butterfly and of birds. Butterflies are the invertebrates whereas birds are vertebrates. The wings in both of them perform the common function of flying but the internal designs and components of these two types of wings are very different from one another. The wings look alike externally because they have a common use of flying. It is an example of convergent evolution.