Figure 1.

Mean values of (a,c) chromatic and (b,d) achromatic matching between eggs assessed by humans as belonging to six different cuckoo gentes in southern Finland and average values per clutch of redstart (n=39 clutches) and pied wagtail (n=22 clutches) host eggs. Bars are standard deviations. Values of matching are sorted by size. Number of host clutches that had a value of chromatic contrast below the threshold value for discrimination ΔS of 1.0 JND are displayed above the bars. (a,b) Phoenicurus phoenicurus and (c,d) Motacilla alba.