Dr. Peter Mojzeš Institute of Physics of Charles University, Faculty of Mathematics and Physic Charles University and Dr. Jindřich Brejcha Department of Philosophy and History of Science, Faculty of Science, Charles University in Prague - conducted the research on a CIRI beamline, studying how parrots produce the colors of their feathers.

The multi-colored plumage of parrot feathers arouses admiration and delight, but where did all these colors actually come from?  How birds managed to develop such a range of colors and how has it evolved over the centuries? A group of researchers led by Dr. Miguel Carneiro from CIBIO (Research Centre in Biodiversity and Genetic Resources - InBIO Associate Laboratory) in Portugal decided to answer these questions. 

Dr. Jindřich Brejcha explained what their research is about - Specifically, we are interested in molecular differences of polyene pigment contained within parrots’ feathers. We use Raman spectroscopy combined with mass spectroscopy to look at the structure of molecules causing parrot color. However, due to the resonance Raman effect for the excitation throughout the visible region and high Raman cross-section of the C-C and C=C vibrations, only a few Raman bands related to the vibrational modes of the main polyene chain and disproportionately enhanced are visible in the Raman spectra. Raman bands associated with vibrations of functional end groups are hidden in stochastic noise. Hence, to overcome this shortcoming of Raman microscopy while preserving the same spatial resolution, O-PTIR microscopy seems to be a promising candidate method.

Why did they decide to conduct their research at the SOLARIS Centre?

- We wanted to conduct a pilot experiment using Raman microscopy correlated with optical photothermal infrared microscopy (O-PTIR) to test in situ whether IR microscopy may be able to provide a more detailed view of the nature of the polyenes in the intact feathers - explains Dr. Jindřich Brejcha.

Picture 1. Detailed view of a red feather of Macaw parrot.

Picture 2. Detailed view of a yellow feather of Macaw parrot.

The CIRI beamline provides access to the O-PTIR microscope, which allows colocalized measurements of IR and Raman spectra with a spatial resolution of approx. 500 nm. IR and Raman spectroscopies are complementary methods and simultaneous acquisition of both spectra is highly beneficial for very demanding samples. Although the studied parrot feathers showed a strong resonance Raman effect, the research could be carried out using IR spectra with a spatial resolution much better than in standard FT-IR microscopy. 

Author of the parrot photo: dr. Petr Šípek

Author of the drawing 1 i 2: dr. Jindřich Brejcha