The most captivating part of nature photography is getting great shots of animals, and the hardest part of this is getting close enough. There's a limit to focal lengths, especially if you're not independently wealthy. Sooner or later, every photographer has to get closer to their subject. And most of the subjects aren't delighted with this.
These are the techniques that have worked for me. It is by no means a definitive list, and you may have good luck with them, or with techniques from other nature photographers. Everyone settles on the habits that work best, and this can vary from area to area, subject to subject.
My background is in animal behavior and habits, so that's been my starting point. While I have no college education in naturalism or biology, I worked for several years with wildlife rehabilitation, animal welfare, and humane education. And the biggest contributor was from rehabilitation. Working hands-on with the animals allowed me to see firsthand what kind of reactions were produced by my own behavior, and how it might differ between species. I also got to work alongside some excellent people who had made a career out of close contact with animals, and some of this seemed to rub off.
Observe — The most basic of rules, but it will work for you if you follow it carefully. Forget everything you know about how humans react, since it doesn't apply. This may seem obvious, but you'd be surprised at the number of people that attach human emotions to animals.
Watch what happens as you approach. Is the animal already aware of your presence? It doesn't necessarily communicate this by staring right at you — that's one of the reasons so many species have eyes on the sides of their head. Rabbits, for instance, will never have their nose pointed straight at you. It'll be pointed in the direction of their escape route, where the depth-perception is crucial — only one eye will be watching you. Watch for alert, balanced poises, often completely motionless. Head will be up. This is your cue to halt — the animal has established an invisible line, and once you cross it the animal will flee.
Watch birds from a distance to see their natural behavior. This can be easiest with species already used to the close approach of people. Observe their flight patterns, where they perch, how much they look around, what they do when relaxed, what startles them, what they do when alert. In time, you'll know what they react to, and thus how to avoid it.
Note times of the day when you see certain forms of behavior. Are the juvenile foxes venturing out? Has momma brought food back? Did something happen overnight? One small trick is to spread smooth white sand somewhere that you suspect nighttime activity — the tracks will be obvious in the morning. You can also do this in any area you visit frequently — look for the subtle changes. An otter that visited a pond where I used to live left behind mollusk shells regularly, and I knew there was a predatory bird visiting my back yard because I'd found feeding remains: discarded parts of other birds, like wings and a leg. These appeared in open areas that provided poor cover for ground predators, but right underneath good perches, so that tells me it's a bird. In that area of Florida, that likely meant accipiters such as Sharpshin Hawks or Cooper's Hawks, or perhaps falcons such as Merlins or Peregrines, all bird-eaters. So I knew what to watch for, and where they liked to feed.
Keep your eyes open, and note any movement. I've gotten a few good shots when a shadow caught my attention and forced me to look directly overhead. Peripheral vision is a tremendous help. Recognizing patterns is a real boon too. Being able to spot the uniformity of a bird's or reptile's camouflage pattern can produce subjects for you seemingly out of nowhere, and body shapes can be obvious if you're watching for them. An example of this can be seen here.
But, don't just use your eyes — your ears are just as valuable. I couldn't possibly count the number of things that I've photographed, or simply caught to examine, because they rustled as I got close. Most birds mark territory with calls, and these will differ from an alarm call (by the time you hear an alarm call, it's usually too late, but pay attention — sometimes other people will spook an animal towards you). Four-legged animals make different noises when walking through the forest than people will, but it's usually a uniform noise. Squirrels can make noise far out of proportion for their size, but it's often scattered and sporadic. Rodents often make rapid gnawing sounds, reminiscent of a dog scratching.
Know your species — This is better if you have a target subject that you're after. Otherwise you can be studying for a good long time to become familiar with everything that might be in an area. What's nocturnal, and will only be seen at night? What likes deep forest? What does it sound like, if it makes any sound at all? (My friends sometimes tease me about pulling out the camera anytime I hear a bird call that isn't routine for an area). Is there weather that it prefers better? Does it migrate? What's it eat? For instance, beavers are strict vegetarians and eat only bark and leaves — otters are carnivorous and will eat fish and shellfish. Osprey are fish-eaters, while Red-Tailed Hawks eat rodents and small birds.
Can you identify tracks? It can be worth having a decent book on animal tracks, so you know not only what shape they are, but what gait they use — alternating or 'hopping', digging, feeling, et cetera.
And yes, keep several books on identifying species. I personally like the Audubon Society Field Guides, since they're easy to find and use photographs, as well as outlining complete habitat and likely behavior.
Don't send warning signs — Again, this seems obvious, but you have to think about it from the animal's point of view.
First, don't talk. At all. Period. No whispering, no baby-talk, no 'oohing' and most especially no 'shhhs'. Really, this comes off as a hiss to animals, and is a threat in any language but ours. Most animal ears are better than ours, and they know what humans sound like, so no speech. And make sure, if you're not alone when photographing, that your companion knows that a fierce glare means "Shut up-a you face".
That said, there are a few noises that it can be okay to make. If you can imitate bird calls accurately, this can often lure one closer to you — usually an aggressive male that's wondering who dares to poach on his territory. I've found a very soft squeak can get the interested attention of numerous species, but make it very quiet and hard to pin down. I've had beavers turn around in mid-stream and approach quite close by doing this, and other species may sit up and raise their ears for a better pose. Owls do some great head bobbing to pin down the source. Use it carefully — if you startle the animal, it takes away your opportunity for more photos.
And by now you're wondering about the autowinder. If your camera lets you shut it off, do so. But don't worry about it too much — I've found the mirror-slap to be much more threatening, and the whine of the winder sometimes masks this by minimizing its impact. Not many species seem to think the winder is an indication of a threat — I suspect it sounds much like an insect. But anytime you can muffle it, or disguise it among naturally-occurring noises, the better off you'll be.
Your attention is a serious thing to consider, too. Once you spot an animal, you'll tend to freeze and stare. The bad thing is, so do most predators, and many animals know this. So try to be aware of when you look like you're about to attack, and avoid it. If the animals is clearly aware of your presence, go casual. Look around, blink slowly, look down (not up - threats come from above). Scratch slowly. Be careful about yawning — it seems relaxed, but opening your mouth can be threatening, and even with dogs it's sometimes an indication of a stressful dominance issue.
I've come under fire with this occasionally, but it works: Birds will preen only when they're relaxed, and imitating preening behavior can allow you to approach a lot closer to birds than normal. When preening, birds slide their beaks down along their shoulders, bob their heads, raise one wing, shrug, and often pause to look around casually. And you may think you look like a fool if you do this (and probably will), but if it gets you that close shot, who cares? I've disguised it by appearing to have a stiff back or shoulder, if that helps. But try it — you may be very surprised.
Some more about birds. Height is security, and being above them is a threat. This is why so many birds have crests — to be bigger than their competition. Birds in an encounter will stretch their necks out, dominant birds will obtain the choicest perches (watch seagulls on pilings or boat masts sometime). So stay lower whenever possible. Fluffing the feathers around their beak hides their only weapon, so is a good sign that they're kindly-disposed, while an open beak is a threat. Ruffling the feathers momentarily is a relaxed sign, usually done before settling down to sleep, while keeping their feathers puffed out is a threatening display. So, raise and slump your shoulders, make yourself smaller. And don't wear your hair up. Take off your hat as they're watching.
Getting back to the autowinder, I've combined looking around casually with firing off the autowinder for a frame while aimed in another direction entirely. This separates your attention on your subject from the sound of the camera, and doesn't let an animal relate them to each other. Seemed to work at the time, but I haven't done it enough to state that it's a great technique yet.
The camera — There's a bit of folklore that the camera lens, especially the larger lenses, looks like an eye. I'm a bit skeptical about this — it doesn't look like an eye to me, and I doubt most animals would be fooled by it. I suspect the few negative reactions from animals have more likely been caused by either the photographers themselves, or from the appearance of something that plainly isn't 'natural'. You won't be able to do much about the appearance of your equipment, but you can control how threatening you yourself appear to be.
I used to routinely shoot with a Canon Elan IIe. This is a camera with the upper portion decorated with brushed chrome — this causes a lot of contrast. I have yet to see it make any difference to any subject I've shot, especially since I used to shoot with an all-black camera. But it does make a difference to how cool the camera stays in direct sunlight. I turned the camera for a vertical composition one sunny day, then waited for my subject to do something interesting. After ten minutes I raised my hand to the black side of the camera, facing straight up, and seared my hand :-). Made me realize that the chrome had been doing a good job, since it had never happened when used horizontally.
Camouflage, blinds, and blending in — You might hear a lot of differing opinions on these. As I said before, this is my experience, and you find what works for you. Because I think that blending in with camouflage and blinds is a complete waste of time. I've been out stalking in camos, in simple olive or grey clothes, and in tan T-shirts with blue shorts — I have never seen one tiny bit of difference in any of them. And I have never used a blind, at all.
Look at it this way: would you be fooled by someone sitting in your living room wearing clothes the same color as your couch? No, huh? How about a sudden new tree or bush in your yard? And remember, you lead a non-threatened existence, unlike most animals. Those people that use blinds on a regular basis know that you have to set the blind and leave it there for a least a few days, and in some cases months, before the animal considers it part of the landscape. And a blind is useful only if you're going to be in it long enough that you can't hold still, and have to eat, drink, scratch, defecate... you get the idea. If the animal sees you enter it, forget it.
Your best results are likely going to be obtained by remaining still. Ever get startled by somebody standing right next to you? It can be that simple. Most animals are oriented to motion and sound, and if you take this away, your chances of being detected are cut at least in half, probably much further. Find a good spot, preferably in shade and away from any path where there's common activity (since the animals will be watching these areas more), get comfortable, and wait. When you have to move, do it slowly. If you think something is going to notice you, or already has, hold still. You have a chance that it wasn't absolutely sure, or didn't see you clearly, and will relax after a few minutes.
This seems to counter the 'don't stare' advice above, but that becomes useful once you have definitely been spotted and are considered a threat. First thing is to try and avoid it. If you fail, then become casual and non-threatening. It won't always work, but it'll increase your chances.
This additionally goes for walking around. Do it quietly — watch where you put your feet, and avoid any noise altogether. Roll your feet gently onto the ground, don't plop them down — reptiles feel the vibrations, and fish (if you're wading) feel the pressure waves. I've walked practically right up to animals with this, coming face-to-face around a bend suddenly. I've also had a woodchuck, avoiding a fox den I was watching, come within six feet of where I was lying; another time a weasel stepped up to the rock I was standing on and sniffed my feet. Not once was I wearing anything to blend in (and not once did I have a camera in my hand, of course). There's simply no beating a low profile.
Once you get good habits, you might get some better results with blinds or blending in, but they're not the thing you should be relying on, and can provide a false sense of security. I've always considered them more of a hassle than they're worth.
Bait — Personally, I've never used it for photography, but others get very good results with it. You want to be careful not to set up an unnatural feeding environment, which is often considered detrimental to the welfare of the animals, but occasional use won't affect anything. Biggest draw, believe it or not, is peanut butter. The aroma carries a long way, and even animals that should have no interest in it will come by to investigate. You have to be careful not to have so much that it can be seen in your shots, though — this tends to be a bit negative. And speaking of negative,
Captive Shots — This method involves some serious controversy in regards to nature photography. There is a large faction that considers it 'cheating' and unnatural, and not the proper challenge that a nature photographer should be facing.
You make your own decisions. My own ethics don't prohibit me from photographing captive animals, but they do prevent me from portraying them as anything else once I've got the shot. If I get it at a zoo, I tell people it's at a zoo. No big deal — if the shot is good enough, you'll still garner attention and respect for it. Most editors don't care, if it fits what they're looking for. Do you think the calendars of wolves and owls have all been shot in the wild? Not likely — both are too nocturnal to allow the kind of photos you normally see in calendars. And there's not one professional nature photographer that I know of that does not have captive shots in their stock.
If and when you do it, you want to still try for as natural a shot as possible. Watch your backgrounds, try to keep walls and fences out of the frame. Even well out-of-focus, the contours or details may show up as too geometrical. Since you have the opportunity, go for close-ups of natural behavior or biological detail, or interesting compositions, portraiture, humor, and emotion. Be creative. A portrait of a lion making an amusing face is still compelling, still sells (quite well, you're likely to find), and is still a lot more effort to get than a human infant making the same face. And do you really think that baby dumped that bowl of spaghetti over its own head? Okay then.
Go where the animals are used to people — There's no beating this, either, and it's the single best contribution to your photos that you can do. I spent a lot of time stalking animals in central New York and North Carolina, but when I went out to coastal NC, all of a sudden I was getting a lot closer and a lot better shots. Then I started taking trips to Florida, and this simply left all other efforts well behind. See the photo in the header? Taken on a fishing dock in Florida, with a mid-range digital point-n-shoot! Great Blue Herons steal bait from fisherman, so they don't mind close proximity because it gets them food, and they realize there's no threat. Florida is simply unbeatable for bird photos, and some areas are better than others. In Wakodahatchee Wetlands near Boynton Beach, you could approach ridiculously close to the birds, close enough that a simple tele-zoom would produce great photos. I left there and drove south, then about twenty miles out the Tamiami Trail (Rt 41), which is probably sixty miles away as the egret flies. I would see dozens of birds from the car, but once I stopped and left the car they would scatter, and I'd never get within 50 meters.
Your area may host some really spooky and cautious animals, and this may make it extremely difficult to get a decent photo, no matter whose advice you follow. It can be worth a trip to another area, solely for photographic purposes. Wildlife refuges can provide a lot of opportunities, and there usually isn't one too far away from anyplace someone might live in the United States. Research your area and talk to other photographers, see where they've gotten the best results. Get out in the woods away from people, find a good location, and just sit and wait. Even when extremely cautious, if the animal doesn't know you're there you stand a much better chance of a close approach (at least for a moment, so be ready). But if you're serious about nature photography, you already have no problem with traveling someplace more productive. My only advice is to keep your options open, and don't fixate, for instance, on a Pileated Woodpecker. Take photos of whatever you see, and whatever will make a good photo. You'll come home with a good selection, you may get some solid stalking practice in, and you won't feel as bad if you didn't actually get a pic of the woodpecker.
And from my experience, very frequently when you're following good habits in the pursuit of a particular subject, many other subjects might present themselves to you. Be ready for them. Have a variety of lenses ready, and keep watching all around you.
I hope this helps. Good luck, and feel free to drop me a line if anything I've passed on to you works out well.