The National Aviary is closed on Tuesday, March 20.

The National Aviary is closed on Tuesday, March 20.

Guam Rail

Guam Rail (Hypotaenidia owstoni)

Extinct in the Wild

 A small bird (only about eleven inches, nose to tail),  all-but-flightless, endemic to the island of Guam.  Common and widespread in the past, now extinct in the wild.  Remaining population carefully managed in mainland United States zoos and select breeding facilities on Guam.

Before 1970, the tiny island of Guam was home to at least 120 species of forest-dwelling birds, 12 of which were found nowhere else in the world.  Then, shortly after the end of WWII, an innocuous brown snake stowed away in an ocean-going vessel and found its way onto the island.  Loose in a land filled with animals not evolved to deal with snakes, and lacking any predators to check its own reproduction, the Brown Tree Snake population exploded.  By 1984, the population of Brown Tree Snakes on Guam exceeded 100 snakes per hectare, and nine of the island’s endemic bird species were gone forever.

Biologists at the Guam Department of Agriculture realized that drastic action was needed if they were going to save what was left of Guam’s native birdlife.  They initiated an unprecedented intervention.  The last of the wild birds on Guam were rounded up and transported to protected breeding areas on Guam and to zoos in the United States.  Three of those zoos – the Philadelphia Zoo, the National Zoo in Washington, DC, and the National Aviary in Pittsburgh (then known as the Pittsburgh Conservatory and Aviary) – were trusted with breeding pairs of Guam Rails with which to rebuild this threatened population.  All in all, a mere 21 Guam Rails were all that kept this species from extinction.

Since then, the National Aviary has lead the way in Guam Rail breeding and husbandry, contributing more than 60 birds to the worldwide population, more than half of which have been returned to Guam.  These Pittsburgh-hatched chicks have been among the nearly 200 individuals released on the neighboring islands of Rota and Cocos, where – without the presence of the Brown Tree Snake, it’s hoped Guam Rails will return to their pre-snake numbers.  When that happens, it will be birds from the National Aviary who helped create the vital genetic reservoir from which the island of Guam will be re-populated.