Before I start I would like to say that these are some of my thoughts and my techniques that I use when I'm shooting wildlife subjects, primarily animal and bird life. There are other techniques that work as well, if not better, than my approach but I'm comfortable shooting my way and if anything I write here helps or makes you think a bit more about your way of photographing wildlife then great
I am also a Canon user, I have absolutely nothing against Nikon cameras but I have used Canon cameras for the last thirty years and I like them. All of the terminology in this piece will be Canon terminology i.e. IS lens are Image Stabilised lens, Nikon call them VR lens.
Something to Consider - Passion
Do you go for a walk and take your camera with you and snap pictures of the occasional bird or squirrel? If you do, then this article probably isn't for you because, in general, wildlife photography needs to be planned, it takes time and ALOT of patience. So you need to decide, maybe months in advance, what wildlife you plan to shoot.
You will need to know, or find out, when your chosen subject will be around to photograph. A good working knowledge of your subject, its feeding habits, its breeding habits, typical habitat, is it noctural? The more you know about your subject the better your chance of getting the image you are after without disturbing the subject.
Personally I will never take an image if I need to disturb the subject. Wildlife has enough troubles without us adding to their problems. I have NO time for people who think their precious photograph is more important than the wildlife.
Do you know if your shutter speed goes up or down when you rotate the dial clockwise? What about changing iso rating or switching from manual to AV or Tv modes? Exposure compensation for backlighting? flash compensation? AE exposure lock? AF exposure lock? Which way do the batteries in the Flashgun go in? All of these questions you should have answers to before you even step out of the house and without looking at the manual If you don't know them then almost certainly you will miss alot of images because you weren't ready. Practise until you don't need to think about how to change a setting so you can concentrate on the getting the image when it really matters.
The Camera - almost any camera can be used for wildlife photography. I've seen some superb images taken with point and shoot (p&s) cameras, but they are limiting what can you achieve. A film or digital SLR camera is best for nature photography. The higher the resolution of the camera, typical 8Mp or higher, the more detail you will be able to capture and, if you need to, it will allow you to crop the image without significantly affecting the result. I prefer to frame my images 'in-camera' to avoid cropping but sometimes that just isn't possible.
The Lens - with p&s cameras you have no choice but if you are buying a p&s camera I would recommend looking for one with a good optical zoom lens. Zooms lens upto x12 are now available and will help you considerably. Do NOT be fooled by the term "digital zoom" it is nothing more than a gimmick that can be reproduced in software like Paint Shop Pro or Photoshop and can be safely ignored.
The dSLR owner is spoilt for choice when it comes to lens. For the average user I would suggest a zoom lens with a decent focal length of at least 300mm. This focal length lens will allow you to get images without invading the subjects space. For the serious wildlife photographer then you cannot better a good prime lens for speed and quality. I personally use a 600mm F4L IS USM Canon lens for the majority of my work or a 400mm f2.8L IS USM lens for closer work.
The quality of the lens is FAR more important than the quality of the camera and your budget should be spend mainly on good glassware not a pretty camera body.
Tripod - personally I believe that you can only get sharp, highly detailed images, using a tripod. It needs to be sturdy and capable of getting close to the ground. Other people will argue that you can get good images shooting handheld, my response is yes you can get good images but I'm looking to get the best images I can without any compromise. I also use a cable release for a lot of my work to minimise any camera movement.
Flash guns - I use flash a lot in my work. It's primary use is to get a catchlight in the subjects eye to make the image ' pop '. I have a range extender called a 'better beamer' that is used to project the flash further when shooting with long lens.
Clothing - I tend to wear camo clothing when out and about but I don't believe it makes too much of difference if you just wear dull coloured clothing. Waterproof clothing, I always wear waterproof trousers, even in summer, as they allow me to crawl around in the dirt and wet grass without even thinking about getting wet or dirty. Waterproof boots are another essential item that you should take along. If you are planning to work near water then waders maybe another item of clothing you will need.
Odds and sods - Scrim net or a small dome hide for hiding in if you are planning to stay in one place. A bag full of string and clips to hold foliage out of the way if I choose to hide in a bush. Poly bags are also useful for waterproofing cameras and lens. Spare cards and batteries for your equipment. Coffee, lots of Coffee
Camera Bag - you will need something to put all the equipment in. There are dozens of good makes on the market but I use Lowepro.
There is a lot of preparation before you even take the first wildlife photograph and it takes time. Notice there isn't ONE image so far
Part 2 - Technique
Part 3 - Image Processing