Does luck play a part in nature photography? Sure - but not as much as you might think. It isn't happenstance that makes great photographs. It's preparation. All the luck in the world is pointless if you're not positioned to take advantage of opportunity when it comes knocking.
Preparation stacks the deck in your favor.
Turns out the boy scout motto applies to photographers, too: "Be Prepared!"
Improve your chances of being in the right place at the right time
Sometimes luck needs a little bit of coaxing. The more familiar you are with an area the better equipped you'll be to predict what might unfold and where the best spot might be to try to capitalize on a given situation. That doesn't mean you can't create some luck in a location with which you have less on-the-ground experience, but it underscores why returning often to the same place is beneficial.
If you're not already, become a student of the weather - and not just broadly. You'll also need to understand microclimates specific to various locations at which you'll be working. Pay attention to the activity of fronts. Be able to identify various types of clouds and know how to interpret them. Monitor cloud cover forecasts. Consult radar. Keep an eye on things like wind speed and the dew point.
Have situational awareness
Unexpected opportunities sometimes sneak up quietly. They can be fleeting. Don't be so focused in one direction or on a single scene that you miss something incredible developing right under your nose, so to speak. Take the blinders off. Check what's happening behind you or directly overhead.
Know your equipment
The amazing light or the double rainbow or the spectacular storm clouds can change rapidly, or move quickly, or be short-lived. (Maybe all three.) If you're fumbling with your gear you could miss it. There's no do-over if you don't catch a mistake until you pull the image off the card. If you don't know how to manage a specific lighting situation, you won't get the shot.
Know which camera settings to select. Understand how to deal with challenging conditions such as extreme contrast. Develop good habits (like bracketing or checking the ISO before you begin). Practice until these things are second nature.
Remove as much uncertainty as possible.
Be adaptable
"Lucky" situations often require flexibility and quick thinking. The composition you originally had in mind may no longer be suitable. Adjust accordingly. Move the tripod. Move yourself. Get higher. Get lower. Go tighter. Zoom out. Switch lenses.
Plan ahead
Consider what you'll require to ensure you can stick around in the field long enough to give opportunity a chance to come calling. If you're being eaten alive by mosquitoes or black flies, or if you're cold, or wet, or thirsty, your concentration will suffer and you'll probably want to bail out sooner rather than later. Be prepared with the proper clothing and things like bug repellent, water, and maybe an energy bar.
Opportunities can be missed if you're unable to get where you need to be. Don't forget the headlamp, or your microspikes, or muck boots, or snowshoes, etc.
Planning ahead also means making sure to have backup batteries and extra memory cards.
Preparation - combined with persistence - will often coax luck out of the shadows. It's not a guarantee (Mother Nature is in charge, after all) but you can dramatically improve the odds.
"Luck is what happens when preparation meets opportunity."
About the Photographs
"Spotlight on Spring" - Grand Teton National Park
My main objective on this day was to capture what I refer to as "green season" so I was working in the north end of the park where aspens are plentiful. The storm was unexpected. I'd been watching it develop but up to that point hadn't found a photograph - until a little crack in the clouds appeared. It looked like a few rays of light might be able to break through. I had to wait and see which direction the light was going to shine before I could compose the shot but speed was the name of the game since the conditions were fleeting. The trees were lit only briefly, but it was long enough.
"Curtain Rising" - Eaton, New Hampshire
With low overnight temperatures forecast, I expected fog over the lake on this early October morning and got it in spades. More than I bargained for. Extremely dense, it lasted for hours - well past sunrise. Who knew how harsh the light would be when the scene finally became a little more clear? That's the thing about fog: it's unpredictable, and once it begins to lift it often does so very quickly. I'd planned on making a wider shot to include colorful foliage on the hillside behind the church. Given the conditions, I had to abandon that idea. The scene revealed itself in a magnificent way and made possible something much better than the photograph I originally had in mind.