Absolutely amazing feather painting. I always never know how to critique something like this because it's a painting that's so amazing that I would never be able to paint right directly when I start drawing.
The feathering and details of the small feathers are very beautiful and on point. The way you tucked the feathers in as it sits is very nice and smooth as well. Even the subtle bark texture is very nice.
I do, on the other hand, have to say that the head is too big. Finches and other big-beaked seed eaters have smaller heads. Most perching birds have smaller, rounded heads and plump, fluffy bodies. The torso proportion is on point, the head is just a little big and flat for this species of bird.
Also, I would suggest a calmer background. Greens and browns are soft and calming colors and the background just suggests a wild and tense picture instead of the calming and cute picture it is. It draws away from the bird and makes the seer focus a little more on the background colors. I would maybe suggest darker forest greens to reflect where the bird is living and maybe reflect it's color.