Great Bowerbirds are not uncommon in northen Australia. The males spend a lot of time building an avenue bower whereby twigs are carefully placed in the ground to build an open tunnel. The bower is paved with light coloured objects and a collection of other objects used in their display to the females is placed in one end of the avenue. The male with the best bower and display will win the females. In this case one of the display objects is a red ballpoint pen. I have seen similar objects in several bowers.