I wouldn't recommend a telephoto zoom lens for photographing small animals. The focal distance will be quite long - in your case around 1 meter or perhaps much greater at larger zooms. Macro lenses give you much shorter focal distances, around 10cm, which allows you to get close to the subject and fill the frame. When I had a camera similar to yours I went for the EF-S 60mm macro and was very pleased with it. A 55-250 lens will be great for shooting birds and distance wildlife and the 55mm end of the range will give you nice wide shots for general photography. Certainly a good addition to your photo kit. I sometimes wish I had a decent telephoto zoom lens and have often considered the Sigma 150-500mm, but whenever I get to the shop I see the size of it and reconsider!