Arizona is spending $1.25 million to build bridges for endangered squirrels over a mountain road so they don't become roadkill and then monitor their health.
The money is being spent, officials said, because cars kill about five of these squirrels each year.
While most suburbanites may be baffled why anyone would protect a pesky squirrel, these are Mount Graham red squirrels, a breed once thought to be extinct. Only 250 of them are known to live near the top of Mount Graham.
The Federal Highway Administration grant will be used to build rope bridges over the lone road through the squirrels' habitat, according to Arizona Department of Transportation Community Relations Director Timothy Tait. The DOT plans to install 41 of the "canopy tunnel crossings" at a cost of $400,000.
Another $160,000 will be spent on cameras to monitor the bridges, and the rest of the money will fund a project to monitor the rodents.
That works out to about $5,000 per squirrel.
The red squirrels have been the subject of much attention ever since they were rediscovered in the 1970s after many thought they were extinct. They were declared an endangered species in 1987 and are now closely monitored by researchers at the University of Arizona, the Arizona Game and Fish Department, the U.S. Forest Service and the U.S. Fish and Wildlife Service.
Tim Snow, non-game specialist at the Game and Fish Department, monitors the population of the squirrels on a yearly basis. He said the population fluctuates from year to year, but it has averaged 250 squirrels over the last 10 years. In the nineties, the squirrels numbered between 300 and 350.
A variety of factors are responsible for the population decline, Snow said.
"The biggest threat to the squirrel is loss of habitat," he said. A wildfire in 2000 destroyed a quarter of the squirrels' habitat, which Snow said is one of two major sources of habitat loss. Insects on the trees are the other major threat.
"The basis of the project is recognizing that traffic on Mount Graham in southeast Arizona is creating impacts on the environment," Tait said. Each day, an average of 650 cars use the lower, paved portion of the road, and 150 cars travel on the gravel portion of the road.
According to Snow, motorists cause roughly five squirrels' deaths each year. Assuming the bridges work and no squirrels die, over 100 squirrels could be saved throughout the 20 to 25 year lifespan of the bridges.
Tait defended the expense of the rope bridges.
"It's a pretty specialized item," Tait said. "They are made of military grade nylon. They're fire retardant and will be dyed a green color to fit in with the environment."
The bridges also have an easy release mechanism that allows workers to disconnect them from the trees in the event that a tall truck needs to drive up to the Mount Graham International Observatory at the top of the mountain, or in the case of a forest fire.
They are called "canopy tunnel crossings" because they include a mesh tunnel through which only the Mount Graham red squirrels – and not other larger squirrel species – can fit. The tunnel will protect the squirrels from predators like birds of prey.