Some species of Molothrus, a widely distinct genus of American birds, allied to our starlings, have parasitic habits like those of the cuckoo; and the species present an interesting gradation in the perfection of their instincts.
Molothrus espezie batzuek, Amerikako txori genero oso berezi bat berau, gure arabazozoen ahaidea, kukuak bezalatsuko bizkarroi-azturak dituzte; eta espezieok mailaketa interesgarria erakusten dute beren instintuen hoberako bidean.