I suspect you'll have a lot of fun with this lens.

The first photo is stellar! (No pun intended; I have no idea what kind of bird it is!)

The others show the range. Only the last one has a fair amount of noise, and I forget how you get rid of that in your settings.

Nicely done!

Keep 'em coming!

That's a gray catbird and the second photo is a Calliope. Third is a mourning dove, which was backlit by the sun in the west. The lighting wasn't ideal this afternoon, but I wasn't going to let that keep me from taking some shots with my new toy.

The last is a turkey vulture which was a few thousand feet above me and shaded. The "noise" is intentional for effect. There are three parameters in the noise reduction section of my post production program: luminance noise, color noise, and detail. For this shot luminance and color noise were at full reduction and detail was at 30% to add some grain.

Birds are not easy to photograph when they're airborne or obscured by foliage. Taking shots of birds at feeders, however, is quite easy. You can get close and they're going to be stationary for longer and more predictable while feeding. When they're in the wild and on the fly, it's altogether more difficult.