First of all - great shots overall - and take my opinions with a grain of shot since I shoot people... :)
on the squirrel: I second the fact that there is something about it that seems lacking - but it is a nice shot. Maybe if you had tilted the camera to the left and kept his tail in the bottom right corner the lines would be more appealing.
on the penguin: I like everything about this - maybe it is too dark, but I still really like the composition.
on the red-chested bird (yeah, sorry I don't know real names

): very nice saturation - maybe place him a bit more off center to make it more interesting.
on the parrot: again, good color saturation - the pipe in the bottom right hand corner is distracting as well as the blue feathers above his head, but otherwise great sharp headshot and nice composition.
on the flowers: not a huge fan of flower shots, but again, nice color saturation.
Thanks for sharing - and again, welcome to the group!!