Whooping Cranes frolick in the River. (Full size view strongly recommended) The Whooping Crane is the tallest bird in North America and one of two crane species found in the US (the other being the Sandhill Crane). It gets its name from the 'whooping' sound it makes. The only natural wild population breeds in Wood Buffalo National Park, on the border of Northwest Territories and Alberta, Canada, and winters at and near Aransas National Wildlife Refuge, Texas. This crane declined from historic estimates of 10,000+ prior to European settlement of North America to 1,300-1,400 birds by 1870 to 15 adults in 1938. This crane has listed endangered since 1967 because it has an extremely small population. Over-hunting, habitat conversion and human disturbance were the main causes of the decline. The 2007 population is estimated at 266 individuals. Early numerous attempts to re-establish breeding populations met with poor to mixed results; more recent attempts have fared much better. The conservation status of the species is improving, with not only increases in the natural wild population but also establishment of two reintroduced flocks that may become self-sustaining. If the number of mature individuals continues to increase, this species may merit downlisting to Vulnerable. Currently, the most significant known cause of death or injury to fledglings is collision with power lines. Powerline markers can reduce collisions by 50-80%, but most power lines remain unmarked and collision is a major and growing problem. Models: Thunder River (Nerd3d), Songbird ReMix Shorebirds Vol 1 (me). Rendered in Poser 7 Pro with no postwork.