There wasn't much noise in the original RAW image (even though the a7R4 produces more noise than my previous Canon 5D4 and it was late in the day... I guess that's the trade-off for the extra megapixels) and when there is too much noise then I run it through Topaz DeNoise AI (that program does magic on noisy photos!). I went back to the original RAW image in LR and increased exposure some, blended the darker background, opened it in PS for some minor adjustments (I left the red raspberry juice on the beak because it was evidence of theft from our garden), and exported as a higher quality .jpg image than before... that seemed to help quite a bit. When I saved as a smaller .jpg file I got some "banding" again. So from what I've seen so far (and my limited knowledge on this subject), it looks like it is mostly a compression issue that shows up in smoother, darker backgrounds... but I'll be watching for this in the future. Also, I didn't use layers in PS, but as Alan Myers said, this would be a good strategy.

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Lots of great information. Thanks to everyone for the help. Now that I have all this new info, I need to dig into this and fix the problems.

Thanks, Paul. That's a lot for me to swallow but I'll check all that out tomorrow when I have more time and I'm more awake. Let's see if I have a rough idea what you are suggesting. ProPhoto RGB has a wider range than sRGB and moving it from LR as ProPhoto RGB to PS I converted the file to sRGB which might have crunched the data resulting in weirdness. Is that close to what you said? I checked some of my other photos and I only see the problem when there is a dark, mostly smooth, mostly green background... and it seems to only be a recent problem. I'm thinking I might have clicked on something that messed up the pixel resolution, especially since I have been watching videos and trying to learn more utilizing LR.

Any ideas what happened when I processed this photo in LR/PS? The top portion of the background is pixelated (I think that is the right term).

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I'm surprised only a couple of people said the Sony a7R4. That would be my keeper, with the 200-600 G lens (better yet, the Sony 600 for only about 12 grand... but nobody would give me enough for my Canon 600 to make that happen). I love all the pixels with the a7R4 for cropping bird photos and the 200-600 is versatile, even if I'm almost always shooting at 600mm, often with the 1.4 TC. Even though the 200-600 is "only" a G lens, and not the supposedly higher quality GM, it is nevertheless quite worthy of a GM status level.

Battery grip or L-bracket would add "bulk" to the Sony. I have Sony a7R4 with Small Rig L-bracket that improves the grip-height and adds a convenient handle on the left side of the body. I sold Canon 5D4 and 600mm f/4... scary move but I'm sure glad I made the switch.

I pronounce it as So Knee

Then my pictures should be as good as yours because I have the same camera with the 200-600 lens (supposedly not quite as sharp as the 100-400 GM since it is a G lens, but field testing results online seem to indicate that both are about the same IQ). It could be that my skills with a new camera aren't up to yours!!!

Beautiful photos... what gear do you use?

Ruby-throated Hummingbird
Blue Jay
Red-winged Blackbird
Common Grackle

Did I get the ID's right? The only one of those in Oregon, except as a rarity, is the RW Blackbird.

If Nikon: D850 and 500PF
Otherwise: Sony a7R4 and 200-600 (better yet, 600 f/4 if affordable). I sold Canon 600 f/4 and 5D4 to get a7R4 and 200-600... very happy I made the switch even though I took a big hit on selling. I have also found I get more good shots with lighter gear because I carry it everywhere now... and with IBIS + OSS I rarely need a tripod.
More is better when it comes to reach... I'm usually shooting at 840mm (200-600 @ 600 plus 1.4 TC) and it still isn't enough in many cases. However, the 61MP a7R4 allows for quite a bit of cropping.

A little more expensive and heavier, but maybe the best IQ: Sony a9 + 100-400 (200-600 even better but heavier).

Also, the female of most raptors is larger... hard to tell unless you see them together. In addition to eBird, Cornell Lab of Ornithology also has an excellent resource site at www.birdsoftheworld.org that is a subscription. Here is an overview of Bald Eagle migration:

Complex pattern of migration dependent on age of the individual (immature or adult), location of breeding site (north vs. south, interior vs. coastal), severity of climate at breeding site (especially during winter but also possibly during summer), and year-round food availability. Most immatures migrate and may move nomadically, presumably because they are not tied to defense of a nest site. Difficult to distinguish between true migration (seasonal movements between breeding and wintering grounds) in immatures and dispersal. Adult birds, in contrast, migrate as needed when food becomes unavailable. Bald Eagles generally migrate alone but occasionally join other migrants on the wing, but not in kettles or flocks. Concentrations of migrants can occur at communal feeding and roost sites during migration.

For BIF I was having a terrible time getting and holding focus with a 5D4 and 400 DO. With the Sony a7R4 and 200-600 it is much better... and probably even better with the a9ii. Maybe I should have held on to my Canon 600 and 400 to use with the R5, but at least I am very pleased with the Sony system once I got used to it. Also, the upcoming Canon R5 should be even better than the current R. As most say, it's the operator, not the gear... and I imagine that was a lot of my problem because I've seen some great BIF pictures with lesser gear than I had.

OK, just to make sure I understand everyone, is an EF lens on an R camera (with the Canon adaptor) going to AF as fast and accurately as it does with a DSLR?

Or... try an alternate approach to a "heavy" lens by doing some upper body strength-building. Worked for me at the young age of 72 and there are additional benefits. I also switched from Canon (5D4 + 600) to Sony (a7R4 + 200-600), not for the weight, however.