Sexual preferences in zebra finch males raised by two species: II. The internal representation resulting from double imprinting

The internal representation resulting from sexual imprinting was examined in zebra finch males known to be double imprinted on both zebra finch, Taeniopygia guttata, and Bengalese finch Lonchura striata. One possible way of storing information on two different species is as two separate internal representations, one for each species (the ‘separate standard model’). This hypothesis was examined by giving zebra finch males, imprinted on either one or two species, preference tests in which zebra finch, Bengalese finch and hybrids of both species were used. For zebra finch males imprinted on both zebra finch and Bengalese finch, hybrids appeared to be more attractive stimulus birds than expected on the basis of the separate standard model. The results seem to fit better an alternative model, which assumes that zebra finch males combine the imprinted information of the two rearing species in one internal representation, consisting of elements of both species: the ‘mixed standard model’. This model can also be used to explain the results obtained in imprinting studies in Japanese quail, on which the separate standard model was based orginally.