DHI allows the recording of a full series of images from a nonrepeatable event which is an appropriate feature for an organic study. This technique uses the backscattering coming from the sample which is collected by a lens that conveys it onto a camera sensor. However, if the object under study presents an uneven scattering response, the interference signal will be compromised. Mind you, the latter is a common response when organic samples are studied using coherent light.34,35 Particularly, the microstructure of the feathers works as an optically rough surface suitable for this technique, however, in some cases they can introduce a diffractive effect.36 This phenomenon is clearly observed with the naked eye in some birds that have iridescent and colorful feathers.37,38 Furthermore, the feathers present different combinations of pigments which can modify the light absorption and therefore the signal response of the interferometric system. Figure 2(a) shows a primary feather that consists of a calamus (or quill), as the section which is physically inserted into the bird’s body. Following the quill, the rachis or shaft is found, where several barbs are attached. A dense mesh grid is formed between the barbs by means of the barbules with and without hooks [see Fig. 2(b)]. This particular structure gives an extraordinary mechanical stiffness but also a light construction. The kind of feather and specimen determines the number of barbs and the form in which they are arranged together.