Wildlife photography is tricky. To get good results does cost money, expensive professional DSLR’s, and pro fast glass costing thousands of pounds. But good knowledge can help you get closer and get good images with cheaper equipment.
Modern cheap cameras such as the Nikon D3100 have reasonable performance and when combined with a good quality 70-300mm lens can produce good results, if you can get close in good light and when the subject is not moving too much.
TV Programs like the BBC Autumn Watch provide excellent inspiration and enable you to increase your knowledge of the natural world.
Whether you have all the gear or just a basic compact, knowledge of your subject and enthusiasm can take you far.