Red factor canaries have been specifically bred to display red plumage. They were developed as a cross between the Red Siskin and the Yellow Canary. Red factor canaries obtain their colouration from red carotenoid pigments in their diet, particularly Canthaxanthin. If there are insufficient red carotenoids in the blood stream at the time of feather growth then the red colouration tends to fade to light pink. This happens when feeding a normal canary seed mix due to the absence of canthaxanthin in seed. Dietary supplementation with canthaxanthin can significantly enhance the colour of red factor canaries, especially in the lead up and during moult.