Why do female common cuckoos usually parasitize one particular host species?

Female common cuckoos typically parasitize one particular host species to ensure the success of their offspring through egg mimicry. Because many host species have evolved the ability to detect and reject foreign objects in their nests, it is highly advantageous for a cuckoo to lay eggs that closely resemble those of the host in color and pattern.12

The common cuckoo population is organized into distinct clans known as gentes. Each gente is specialized to parasitize a specific host species for which the females have evolved matching egg coloration. Research suggests that a female cuckoo typically restricts her parasitism to the same host species by which she was reared, a preference likely established through a learning process during her time as a nestling. By consistently targeting a host whose eggs match her own, the female significantly reduces the likelihood that her eggs will be rejected, thereby increasing her reproductive success compared to laying eggs randomly.123