This explains how cuckoos can evolve diverse eggs yet remain one species.

Mothers control egg color, while patterning reflects biparental variation tied to geographic and host context. This dual system stabilizes mimicry without necessarily driving speciation. 5/6

Egg patterning instead appears to be controlled by many biparentally inherited genes.

These nuclear loci allow local adaptation to hosts and geography, but they don’t drive full genomic separation between cuckoo host races. 4/6

In common cuckoos, egg color follows maternal lineages.

A candidate gene involved in eggshell coloration shows evidence of an ancient autosome-to-W translocation, while other nearby loci tie coloration to mitochondrial function and the heme pathway that produces pigments. 3/6

Common and Oriental cuckoos sneak their eggs into other birds’ nests.

Common cuckoos parasitize over 100 host species, fueling an evolutionary arms race: hosts are under pressure to detect foreign eggs, while cuckoos refine their mimicry to escape detection. 2/6