Telling them apart

If you didn't know much about birds it wouldn't be hard not to know both these little fellows were the same bird let alone the same species. This poor one has just started his annual moult after feeding his babies none stop for the past few months. He also got completely drenched and water logged so was sheltering in the cycle shed until he dried off a bit. We did finally get some sun shine as you can see this pair of Siskins enjoying. Are those Niger seeds sprouting in the feeder? Looks like it from here.