"...I don't have access to these cameras for real-world comparative analysis..." Actually you do Geosailor... Rent before your even think of buying... Even then go with "Previously Owned" from a vendor who will allow you to return it if it doesn't meet your expectations... i.e. KEH; mbp; B&H ect...
"...I'm in the market for a new camera..." Why Geosailor, your D7000 is more than capable (in skilled hands) of turning this hat trick without even breathing hard. It's your optic that is limiting... as Paul mentioned "Bird" photography starts at 400mm (minimum).
"...I'm left with getting opinions from folks with more experience..." Something that is typically in short supply... Unless you pony up the fee for a "Hands On" seminar from the likes of a highly skilled "Bird" photographer such as Steve Perry
https://www.uglyhedgehog.com/user-profile?usernum=60547 Get on Steve's web site if you are serious about bird photography.
I would also suggest you join flickr and become a member of many of the groups devoted to "Bird" photography... Study their masterful work... The best thing about flickr is there is very little BS since flickr posts the actual EXIF data from the photographs... So you get a valid window into what it takes.
Food for thought: Wildlife photography is for those who are independently wealthy... It (along with Sports photography) demands Pro-Level kit. Maybe rethink going down the bottomless rabbit hole... Just saying...
Final thoughts? Your D7000 can easily handle this mundane shot of a "Sitting Duck" or eagle in your case... You seriously need to capture your Bird In Fight otherwise referred to "BIF" to gain any real traction or recognition from your photographer "peers" As others have said, you actually may need considerably more training, NOT a new camera, albeit consider a decent optic (that can approach reaching an "angle of view" of over 400mm.)
Below is a BIF capture with a D7000... Your issue isn't with the D7000 Geosailor... It's with the optic you decided to mate to it... and very possibly your skill-set: Oft said "It's a poor craftsman who blames this tools for want of success..."
Hope this helps... and please give flickr a try, there you'll find some breathtaking imagery and talent...
One of the many flickr "birding" groups
https://www.flickr.com/groups/bird_photography_excellence/Cheers!
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"...I don't have access to these cameras for ... (