I've been tryin to get a good shot of a Flicker for I don't know how long , and here you are trying a new lens shhoting one.
Congrats on your new lens. Very nice shot.
Socrate
Nice flicker, that is bunch of lens with that 1.4x. Looks like you had the ISO way up(lot of noise in blue BG) or did a lot of sharpening which meant perhaps the image was not as sharp as you wanted. Going to take a nice steady shot at a higher shutter speed 1/1250+ for sharp shots. Once you nail one you will see it, will be amazing. Good start and they will get better as you continue to get used to this setup and it's results.
Enjoy the new toy and looking forward to future posts and hopefully some improved shots. This one is a bit fuzzy and a lot of noise in the BG. But sometimes it takes a bit to get used to a lens
Congratulations on your new lens. I think you will have a lot of fun with it. The small size is amazing for a 400 F4 lens. One word of caution on the DO, while I have seen many fine images with the DO and a 1.4x TC, I had a bad experience with this combination. The DO that I had for awhile was very sharp at 400mm but when I added a TC, it became very soft. This image looks a bit soft to me but there are many potential causes. However you might want to shoot some at 400 and then again with the TC to see if there is a noticeable difference in image quality. Enjoy your new lens!