07 Oct Off
The Phoenix Zoo and the U.S. Fish and Wildlife Service announced a 10-year pilot program this month that seeks to establish a successful method for breeding Mount Graham Red Squirrels
The Mount Graham Red Squirrel has lost almost half of its population over the last 15 years, leaving less than 300 to roam its only home in the Pinaleño Mountains
Their housekeeping habits help replenish the forest floor. They bury their food at the base of a tree and leave their scraps — bones they found, unwanted leaves or pine-cone chunks — in piles around that tree. Those scraps often spawn a micro-habitat where saplings may germinate and grow.
The Phoenix Zoo has experience bringing back creatures with similar difficulties, including black-footed ferrets.
The endangered Mount Graham red squirrel has lost nearly half its population over the past 15 years, leaving fewer than 300 to roam their only home in the Pinaleño Mountains in southeastern Arizona.
This month, the Phoenix Zoo and U.S. Fish and Wildlife Service launched a 10-year pilot program to establish a breeding program to prepare for possible future habitat degradation that could wipe out the rodents.
The project begins with just six squirrels that staff hope to breed, and will expand to other zoos.
And that’s a challenging feat, considering the fact that female squirrels have only an eight-hour window each year in which she may mate.
The rest of the time? The squirrels are so territorial that one will attack another if it crosses its turf. Sometimes it’s a fight to the death.
That leaves the zoo’s Conservation Center on a fragile line — the experts will have to monitor behavioral and physiological changes to know precisely when to put a male and female together.
The experts say it’s worth the effort.
“At a first glance you’re like, ‘What’s the importance of this squirrel? It’s a squirrel,’ ” said Stuart Wells, director of conservation and science at the zoo. “But if they were absent, it might play an integral role of the ecology of that mountain range.”
That’s because their housekeeping habits help replenish the forest floor. They bury their food at the base of a tree and leave their scraps — bones they found, unwanted leaves or pine-cone chunks — in piles around that tree. Those scraps often spawn a micro-habitat where saplings may germinate and grow.
Without the squirrels, the forest could wind up with more desert-like conditions, Wells said.
But it is unclear exactly how drastic a difference their demise would create.
“It’s probably not worth the gamble,” Wells said.
Separated from other red-squirrel populations since the last ice age, the Mount Graham red squirrel is a subspecies of the North American red squirrel. It exists only in the Pinaleño Mountains in the Coronado National Forest: a “sky island” of life surrounded by desert, created when glaciers recessed about 10,000 years ago, according to the zoo.
Their limited habitat leaves them vulnerable. Two large fires scorched 35,000 acres of their land in 1996 and 2004.
Extended drought, forest insect outbreaks and tree diseases have hampered their home. And a separate species of squirrel from the Grand Canyon, brought to the Pinaleño Mountains decades ago for hunting, means less food to go around.
On top of that, the forest canopy has yet to recover from forest fires in many areas, which leaves the squirrels in plain view of hungry hawks, Wells said.
The squirrels have also weathered controversy surrounding the University of Arizona’s observatory, including three telescopes installed in the late 1980s.
Conservationists had protested the site, saying that it would harm the red-squirrel population.
As a condition of its permit, the university is required to monitor the squirrel population.
The university states on its website that its staff of five biologists have found no signs that the observatory construction affected the squirrels.
The Phoenix Zoo has experience bringing back creatures with similar difficulties, including black-footed ferrets. They have short windows for mating and are also territorial, Wells said.
Thirty years ago, only 18 black-footed ferrets were known to walk the earth. Zoos, including the Phoenix Zoo, brought them in, bred them and released them. Now there are about 1,200.
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