What stands out most as one looks at your photo is what counts. If blur stands out, then your photo will be viewed as out of focus. The background of your images are blurred. This could be because of the settings of your camera. If you do not want a recognized view of your subjects background, the suggestion is to fill the view with the subject. If you're including the background, then it should be sharp. The bird is too small and too much blur in the first photo. The second, the water above the bird is blurred. The third, the water below the bird is blurred, Your hand seem to shake while taking the third photo.
The images of the birds are not sharp, for example the Mallard duck in flight:
I'm afraid all of the bird photos are like this - hence the reason 'out of focus'. There isn't really anything you can do to sharpen them.
I noticed you used f 2.8 in your metadata - this would be a reason for blur as you did use a fast shutter speed 1/4000 sec. A smaller f-stop (aperture) would be better in this situation as f 2.8 doesn't give you any depth of field especially with a telephoto lens.