There is a world somewhere between reality and fiction. Although ignored by many, it is very real and so are those living in it. This forum is about the natural world. Here, wild animals will be heard and respected. The forum offers a glimpse into an unknown world as well as a room with a view on the present and the future. Anyone able to speak on behalf of those living in the emerald forest and the deep blue sea is invited to join.
The Sony here is a mirrorless camera. I am not that knowledgeable on them, but from what I know they are compact and lighter than DSLRs, but have slower autofocus and lower battery life, although that might depend on the model. Also, DSLRs come with a huge assortment of lenses, so if you want to buy a new lens in the future, you would have a far bigger choice with DSLRs. Remember, you're not just buying a camera, you're also getting into a family. A nikon lens won't fit on a canon and vice versa. Similarly, lenses for mirrorless cameras and DSLRs are different. The Canon rebel is a DSLR, however, both the sony and canon look very good deals on paper.
With wildlife, you need to have fast and continuous autofocus, since the subjects are constantly moving, and the ability to shoot continuously. So you need to take these factors into account. I am expecting Image quality to be similar for both. So you might want to check both the models (along with the Nikon) in a camera shop, take a few snaps, check how fast they focus in low light, how fast they can shoot on burst, image stabilization, body build, and overall feel and see which one you're more comfortable with. Don't just order online.