I was sitting in my Leonard Lee Rue photo blind at the edge of our pond/lake (actually a dammed up section of river), waiting a long time for the Common Mergansers to swim within camera range, my feet getting cold in the chilly, raw weather. The mergansers and other ducks were far off, and did not come into the cove at all.
I was just about to leave when I heard a scratch, scratch, scratch on the roof of the blind. Hmmm. Wondering what that could be, I looked up at the roof, through the crack where the blind closes, and looking down at me was a Black-capped Chickadee. We both jumped at the same time.
The chickadee proceeded to land in the bush next to me, giving, in it's loudest voice, a string of "chickadee-dee-dee-dee" call notes. It clearly did not approve of me being there.
I decided to quickly change my camera from the long Canon 500 mm lens to the 300 mm IS shorter lens, which I hand held and quietly and slooowly stepped out of the blind. The chickadee did not move and continued to give me a piece of it's mind. Click, click, I took a few photos then went slowly back into the blind. The chickadee hung around for a while, was joined by a second chickadee, then off they went.
Nature is always offering you something, but not necessarily what you had in mind. When opportunity knocks, change lenses and get the photo.