The call of the Red-winged Blackbird is a familiar sound in most marshes.  They are very territorial and they will defend fiercely, even attacking much larger animals to protect their nests.  I once witnessed a Red-winged Blackbird attacking a Great Blue Heron while he was focused on fishing an area that was obviously too close to a nesting site.  They are a polygynous species where one male can have as many as 15 different females in one breeding territory - hence the name of this piece.