Yo, just saw your post and honestly, dont let the numbers freak you out too much. For the Everglades, you definitely need reach because gators dont exactly invite you for a close-up lol. Since you have a $900 limit, I would suggest looking at the Canon RF 100-400mm f/5.6-8 IS USM. Its super light which is a total lifesaver when you are hiking in that swampy humidity for hours. You might want to consider that its an f/8 lens at the long end tho. Basically that means it doesnt let in a ton of light compared to the massive pro lenses. Be careful if you are shooting deep in the mangroves or right at sunset because your photos might get grainy. But for around $600, its a steal and it fits your R7 natively without needing any extra parts. If you really want more zoom, you could try the Sigma 150-600mm f/5-6.3 DG OS HSM Contemporary for Canon EF but you will need the Canon Mount Adapter EF-EOS R to make it work. Just a heads up... some R7 users report the focus pulsing or jumping around with that specific Sigma lens. It can be super frustrating if a bird is about to fly away and the lens wont lock on. Personally, I would stick with the Canon RF glass first to keep things simple while you are still learning. Make sure to grab an extra battery for the trip too, the R7 eats them up when you are using the animal tracking mode constantly.

Hey! So stoked you grabbed an R7, it is a total beast for wildlife! Since you are heading to the Everglades, you basically want as much reach as you can afford. Reach is just a fancy way of saying how far the lens can see. Because the R7 is a crop sensor camera, it actually multiplies the zoom by 1.6x, which is like a secret superpower for getting close-up shots of birds and gators without actually getting eaten lol. If you want to stay under that $900 limit, I would definitely look at these options:

• Canon RF 600mm f/11 IS STM is honestly so cool because it is incredibly light and tiny. You can carry it all day without your neck hurting and the zoom is amazing for those far away herons.
• Sigma 150-600mm f/5-6.3 DG OS HSM Contemporary for Canon EF is a huge favorite for a reason. You will need a mount adapter to make it work on your R7, but having the ability to zoom in and out is so helpful when wildlife is moving around.
• Canon RF 800mm f/11 IS STM might be a bit much for a beginner, but if you can find a used one in your budget, it is like having a telescope attached to your camera. I really think the 600mm prime is your best bet for a trip like this. Just remember these lenses need a lot of light to work their best, so they are perfect for sunny Florida days! You are gonna have a blast out there. Seriously, dont sweat the technical stuff too much yet, just get out there and start clicking!

No way, I literally just dealt with this yesterday. Small world.