In his classic motion picture "The Birds," Alfred Hitchcock envisioned hostile avian armies that intelligently coordinated their attacks. Before you dismiss this as the stuff of pure fantasy, take a trip to the sunny woodlands areas of sub-saharan Africa.

Many species of birds play the role of soldiers, patrolling the edges of their territories to repel invaders. But the Green Wood Hoopoe takes it a step farther, banding into an integrated, disciplined platoons of members that work together to defend their African homeland.

Up to twelve birds function as a single unit, coordinating their cackling calls in a warning meant to ward off intruders. Experiments show that the birds are actually cooperating -- taking programmed individual turns to produce as much noise as possible -- and will coordinate their beak-to-beak vocalization in an escalating effort to match recorded calls that seem to threaten their territory. Just as human soldiers may give each other a high-five after successful combat, the Hoopoes also groom and congratulate each other -- the most respect going to the birds that mustered the most intense defense.

But the real-life incident that inspired Hitchcock's thriller had a more mundane cause -- the 1961 kamakazie attacks by seagulls on California homes were caused by an epidemic of poisoning from toxic alga contaminated by leaky septic tanks.