• Thu. Dec 1st, 2022


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Male crossbills grow redder feathers when they exercise harder

The red feathers of male crossbills are brighter in birds that find it more physically challenging to fly, suggesting exercise influences plumage colour

Life 7 April 2022

Common Crossbill

Male common crossbill (Loxia curvirostra)


In a kind of post-workout glow, male crossbills that work harder when flying will grow redder plumage. The findings reveal that the processes that generate red feather pigments in the birds may be partly driven by the revving of the metabolic engines inside cells, called mitochondria.

Many animals acquire their bright colours from compounds in their diet. Male common crossbills (Loxia curvirostra) take in yellow carotenoid pigments from their food and use enzymes to convert the pigments into vibrant, red ketocarotenoids, stored in the feathers.

Scientists …