As I have Goldfinches in my back garden, I get a lot of pictures of them, as most members well know, they will also know that 8 times out of 10, there isn't as much detail in the bird as there could/should be. Goldfinches are a hard bird to get real detail in them, the same as Barn and Tawny Owls. I don't think it is anything to do with the ISO or crop, just the fact that the bird, generally, doesnt give as much detail as other birds, such as, the Blue Tit.

Ron, I do like the image, but maybe a little NR on the B/G would make it slightly better, or removing the branches. Don't wish to make any disturbance. Just a point of view.

Excellent Harvey. I know what you've done to make this effect, but you should turn down the radius because as you can see above the head, mainly the left side, there is an extra white 'Halo' Where you have turned the radius up and has pushed the white out.

Good capture Kieran. Personally a shutter speed of 1/30th second is too slow really. Anything above 1/60th second is alright. But with that shutter speed I like the way you have captured the rain like that. Well done