You've seen them before. An image where the subject seems to be suspended within a sea of white. Referred to as "High Key", it's a pretty simple task to accomplish right within Lightroom once you've become proficient with the Adjustment Brush tool (See "Getting to Know Lightroom's Adjustment Brush")
I was intrigued by the mid-air acrobatics of one of our hummingbird friends and, despite it being a noisy, background cluttered image, I thought maybe we could make something out of it. Here's the original image.
Using Lightroom's Adjustment Brush, I selected the area surrounding the hummingbird being careful to us a softer edged brush around the "wing blur" and a brush with a more defined edge for the rest. Once satisfied with my selection I moved the Saturation and Clarity sliders for the selection all the way to the left and pushed the Brightness slider to the right until I achieved a pure white background.