This image nicely captures a face off between two bluebirds. The loser is ducking away from the winner who stands threateningly over him. Capturing animal/bird behavior is often as important as compositional rules when trying for a compelling photograph. This image also makes good use of compositional rules such as the rule of thirds (winning bird's eye on top horizontal line and losing bird's body near a vertical line). The image also uses a shallow depth of field to isolate the birds from the background and draw further attention to the behavior.

