How much is too much to spend on saving an endangered species? In the case of the endangered Mount Graham red squirrel (Tamiasciurus hudsonicus grahamensis) $1.25 million seems to be the breaking point.

The Arizona Department of Transportation (ADOT) recently announced it would spend that much to protect the squirrels from cars near two dangerous roadways where several of the animals die every year.

The news was met with vocal protests, from citizens and government officials, and the plans have now been cancelled. ADOT director John Halikowski did not admit that protests caused the change, but told news channel KGUN-9 that his department would rather refuse the federal grant money intended for the project than spend it on the squirrels. "ADOT will not spend funds simply because they are available," he said in a prepared statement. The federal transportation grant, which was not specifically earmarked for the squirrels, cannot be used for road repairs or other construction projects.

Arizona is in the middle of a budget crisis that has forced ADOT to close rest stops and delay road repairs.

The Mount Graham red squirrel, one of 25 red squirrel sub-species, was believed to be extinct from the early 1950s until it was rediscovered in the 1970s. It was added to the U.S. endangered species list in 1987 (pdf), and the U.S. Forest Service has conducted an annual census of the squirrels since 1986. After a brief population surge from 1998-2000, the squirrel count has now plunged to about 250 animals, making it the world's most endangered squirrel species. Drought, forest fires and loss of habitat have been blamed for the decline.

The $1.25 million plan included $400,000 to installed rope bridges (called "canopy tunnel crossings") across two roads on Mount Graham. Another $160,000 would have been spent on cameras to monitor the bridges, with the rest going to radio collars and other long-term efforts to monitor the squirrels.

Tim Snow, a specialist with the Arizona Game and Fish Department, told ABC News that, on average, five Mount Graham red squirrels are killed each year by motorists. He said that if the bridges had been installed, and if they worked, it would have saved 100 squirrels over the bridges' 20- to 25-year lifespan.

So would the bridges have worked? Sarah Bergman of The Center for Biological Diversity told KGUN-9 that they probably would have: "We've been seeing success with tree squirrels in Florida actually using a very similar canopy structure...We've also seen some success in Australia where they've been decreasing mortality rates there for species that have this additional safety net." As for the cost, "$400,000 is a tiny amount of money to spend to save an entire species," said Bergman.

Photo via Wikipedia