A marsh wren (Cistothorus palustris) briefly pauses on the dead stem of a cattail to survey the surroundings. Based on territorial behavior and singing, the wren is likely a male. The energetic little bird took cover under the dense mat of dead vegetation shortly after this shot. This is one frame of several that mark my first for this species.
Canon Rebel XSi (450D)
Canon EF 300mm 1:4 L IS USM
Canon EF 1.4x II Extender
420mm, 1/500, f / 8, -1/3 EV, ISO 640