Marg, here's a merged view of the original surrounded by two example edits. If you look into the fine details, they all are hampered by the limitations of the original. But, they also show the opportunities. I think removing the window is the first major opportunity. The other ideas should be experimented with (shorter focal length and crop, lower ISO, wider aperture, single focus point, capture in RAW, process in LR or PS or both, using a tripod). I'd experiment in better light so I could compare images from f/8 > /f11 at 300mm at a lower ISO with the same exposure at 200mm ish and cropped. Some of the ideas are somewhat contradictory, so try various combinations and directions, where possible. Glad to hear you enjoyed my IG feed.

This is what I could get out of one of your pictures. I used Photoshop using High Pass filter on Rufus.

When shooting I would try not to go over 1200 iso on your camera to reduce your noise. In this shot iso 1200 and f/5.6 might work, if not then go to a little slower speed. You can open shadows and under exposed files easer if you shoot raw. I always shoot in raw to have all the information I can get out of a shot. It then lets me fiddle with the sliders with more control to get what I need.

One of the often overlooked source of softness is caused by image stabilization trying to compensate for non-existent camera motion. If you are taking a photo using a good tripod and a shake proof shutter release method, then by all means turn off your camera's/lens' image stabilization feature. (Even worse is if the camera and body each have their own competing versions of image stabilization turned on. But your Canon body, I don't believe, has internal image stabilization so if any IS induced blurring occurs it would have to come from the lens' IS.)

Yes, the phone was the culprit.

Coming back to your original question, yes some editing can help things. From the data in the image from the camera, one additional change would be to use just one focus point. In this example, the center would be fine for the distance and cropping opportunity. Whatever point is used, try to set it directly on the bird's head or eye. See the screen capture that shows a group of AF points active rather than just a single. Try with a single point and see what you can get.

"Creative editing" can be interpreted so many ways, such as shown by the alligator composite someone posted to your other topic

Since you mention wanting to improve the image, I'm thinking you are referring more to elements such as clarity, contrast and color. Shooting through a window into flat light are challenges that are difficult to overcome with simple edits. In the other topic you mentioned you would try increasing your shutter speed to 1/800 second, but that will require an additional adjustment: either raising your ISO, which is already high for that camera and lens - meaning overall image quality is likely to be better with an ISO under 1,000 - or changing your aperture to a smaller number (which affects depth of field).

Because the quality of light is such a huge aspect of photography, here is a discussion topic currently in progress in one of UHH's specialty forums, For Your Consideration:

http://www.uglyhedgehog.com/t-529331-1.html

Hope you'll check it out!