The aim of the second test was to determine whether breeding
experience influences the choice of nest material. Half of the
breeding pairs were provided with the nest material preferred by
the male in the first test and the other half were provided with
the male’s nonpreferred nest material, ensuring that each fibre
colour preference was equitably represented in these two groups.
To manipulate breeding success, Muth and Healy then allowed
half of the pairs in the group that built with the preferred colour
of nest material and half of the pairs in the group that built with
the nonpreferred colour of nest material to incubate their eggs,
fledge chicks and care for them. This was the ‘successful breeding
experience’ treatment. The other pairs were allowed to incubate