CIBIO Research Centre 

Illustrations developed in light of paper published in Science Advances (Evolution and genetic architecture of sex-limited polymorphism in cuckoos | Science Advances) that leans over a genetic mutation, which occurred a million years ago, that affects the colors among cuckoo females. There are females cuckoos that are sometimes gray, sometimes reddish (or “hepatic”), This characteristic of females has been observed in the European song cuckoo (Cuculus canorus) and its sister species, the eastern cuckoo (Cuculus optatus), as well as in other species within the cuculid family. Thus, the mystery of this intrinsic natural variation in color in a species, sometimes limited to a single sex, is finally clarified in this paper.

These illustrations were later on published on Público newspaper  (on an article entitled "Desvendado um mistério centenário sobre a cor dos cucos") by Teresa Firminino, on April 2024) and on the news page of Porto University (https://noticias.up.pt/2024/04/26/cientistas-da-u-porto-desvendam-misterio-secular-sobre-a-cor-dos-cucos/).