At present, Sony A1, Nikon Z8/Z9, and Canon R5 are the best cameras for bird photography in the wild. The Sony 200-600 zoom, Canon 100-500 zoom, and Nikon 180-600 zoom are all well regarded; the Canon 200-800 is a little soft for my tastes. I have used only Canon equipment. The R5 is the closest thing to a 1DX if you are not just interested in stills photography (in which case you might prefer the R3). It has a full-frame, rather than APS-C, sensor like the R7. It is "about" to be updated to an R5 mark II. The biggest difference between DSLR and mirrorless (MILC) is the focusing physics: photography of birds in flight and birds that fill a reasonable portion of the frame are much better with MILC, low-light/slow shutter-speed photography is much better with MILC, but focusing on obscured birds or birds that fill a tiny portion of the frame is still better with DSLR. It took me nearly a year to become fully adjusted to the behavior of MILCs and I am still waiting for better autofocus on small subjects and better recognition of bird eyes...but I'm sure it's coming. The great aspects of MILCs--birds in flight AF, eye AF, and high signal/noise (high ISO) capabilities are why I switched MILC.
Hi Brad and thanks for the answer.
The point or the plan i keep telling myself about is to let that 1D3 [and 30D maybe] to go first, and replace it with something new either latest model or at least something that is out in this last 2-3 years, definitely they should be way ahead better than 1D3 and 30D, and i saw that R7 is the closest i can think about for price and performance, then later when i feel that i am ok more with mirrorless camera and get used to it more and i keep doing photography then i could think about a replacement/upgrade of 1DX too, i watched some YouTube videos where people are still favoring that 1DX line [mk1/2/3] over some MILC, even some still keeping old 1DX against their R5 or R6, and someone mentioned that although that R3 is a fine camera but it has few cons as well, so for me i feel like i can't risk about going that because i won't have any good price for 1DX now, but later i might save something or get paid so i can fund a newer replacement to 1DX, while for R7 i still can buy it even if i didn't sell 1D3 and 30D, but i will eventually.
I also still have 5D classic and 1DsII and 1DsIII, those i also can sell with my Sony A7R so then i can buy like best 2-3 cameras new generation, i was thinking about like Sony A7R6 + Canon Rsomething and maybe Canon R7, this way i am all done, i bought new cameras in the past without selling older models until i just kept many of them around in bags without dust, if i can manage to let say 5-6 bodies go and add more budget a bit then i can buy another 2-3 new bodies, the point is that i don't work [jobless] so that i am always in tight budget and slowly i can save, if i work again then i won't ask.
For lenses, it is a pain in.... when seeing those brands/manufacturers keep making new lenses all the time every year making us confusing about keeping our old new lenses or keep selling and keep buying, i remember when i sold my 70-200 f2.8IS mk1 to get mkII Canon didn't wait long and produced MKIII, i decided to stop buying, it became like a very silly idea keep buying same lens model into newer versions, so now after like 10-14 years i am ready to upgrade for another decade or half decade, and i have to be careful on what to buy, it sounds that most are moving towards MILC leaving DSLRs behind, i can't move completely to MILC yet, but i will try slowly move that once i feel that i am not longer needing DSLR performance, but for lenses i can't also sell all what i have to buy new things, i still have fine strong lenses which were expensive back then such as 300 2.8 mk1 and TS 17/24 and 70-200 mk1, even my 100-400 wasn't cheap but i can think it is no go at all for me now, for still photography i don't need DSLR anymore, while for sports and fast actions maybe i will hold on DSLR for another few years until it is no longer the option.
