It's never an easy task to photograph the itsy-bitsies of the bird world. They almost never stop hoppin, flying, jumping, flitting, you get the point.
Blue-gray Gnatcatchers are a tiny, long-tailed bird of deciduous forests and scrublands, & makes itself known by its soft but emphatic "spee" calls and its constant motion. By flicking its white-edged tail from side to side, the gnatcatcher may scare up hiding insects. (Source: All About Birds)