Hi Sue.
I have just submitted another picture of a gull in flight. I think you will like this one. It was taken with a 300mm lens. You will need something of that size for wildlife work.
I would strongly advise that before purchase anything, you get hold of the equipment just to see how it feels in your grip. Check to see how the controls fit to your grasp. You might find that the gear that we have mentioned is not too your liking, unlikely, but you are the one that is going to use it. Only you can say if you are happy with its weight and how it feels etc.
One other thought, if you can visit a good, dedicated photographic store, you might find that there is some reasonable second hand gear on sale. Photographers, when upgrading sometimes put their old equipment in as part exchange. In the past I have picked up decent equipment in this way.
If you do decide to buy a telephoto lens, you will find that there are a lot of different makes available for your new camera, apart that is from original equipment. Whatever the make of the lens you choose, as long as it states 'canon fit' it will work with any SLR canon camera.
Anyone you talk to will have their favourite make of lens and again that is a personal choice and I will not try and influence you in that way. Just see what is available, but get the feel of it and try it out before you buy it.
Regards Roy.