Fig. 7. Distribution of criteria 1 and 2 for absolute photorefractoriness among four species of cardueline finches. Criterion 1 indicates whether or not the species spontaneously regresses gonads on constant long days [data are taken from: ¹(Hahn, 1995); ²(Hahn et al., 2004); ³T.P.H., unpublished data (based on molt and cloacal protuberance)]. Criterion 2 indicates whether or not the species responds to very long days when putatively photorefractory (data from this study). Phylogeny based on Marten and Johnson, and others (Marten and Johnson, 1986; Badyaev, 1997; Arnaiz-Villena et al., 2001).