The passenger pigeon was once probably the most numerous among birds on the planet. It was found in the vast forests that covered North America, east of the Rocky Mountains. Flocks of passenger pigeons were huge- often one and a half kilometers wide and up to 482 kilometers long. Passenger pigeons became extinct because their immense roosting and nesting colonies invited over-hunting. The last reported sighting of a flock was in 1896
The Arabian ostrich once lived in the Arabian Peninsula, and in the Near East. Ostrich hunting was a popular pastime of the rich. So, the Arabian ostrich became very rare. The last confirmed specimen was shot in 1941.