This is a wonderful shot of a pair of Serinus canaria, the original wild canary. Do please note that they are not "canary yellow"! I couldn't tell you how many people I have heard look at a green canary and say, "But that can't be a canary - it's green!"
It is true, though, this was the original colour of the wild canary. Yellow, and all the rest of the wide range of colours canaries come in, came later, after people began selective breeding. Although the domestic species still has very much in common with its wild cousins, there are differences, too, and this photo shows some of them quite clearly.
This is a breeding pair of wild canaries - the hen is on the left. It is possible to tell this because unlike many of their domestic cousins, the genders of the wild birds show subtle but distinct differences, similarly to other species in the carduelan group.
Can you spot them? The hen's outline is subtlely rounder than that of the male's - the slightly greater edging to her feathers, thus making them a little broader than his, tends to make her appear to be a little less slim than he looks to be. The colour in his feathers shows a little more brightly, particularly in his face, for lack of this slightly broader edging to the feathers.
But the most noticeable difference of all, to my mind, is in the markings on their flanks, generally called 'striations'. Hers are distinct and clear, while his are almost completely lacking.