Birdcage

At the front a Birdcage was the colloquial term for the enclosure, surrounded by barbed wire, where prisoners of war were herded together during action previous to being marched to camps in rear. The names was also used for any military prison or detention quarters. "The Birdcage" was the name universally given to the elaborately entrenched position, north of Salonika, constructed in 1916 to serve as a final stronghold in the expected event of an overpowering attack. It was designed for the same purpose that Wellington constructed the Lines of Torres Vedras.