The population of endangered Mount Graham red squirrels in the Pinaleño Mountains near Safford declined this year after increasing slightly in 2014, state and federal wildlife agencies reported Friday.
An annual survey of the squirrels found an estimated 263 animals this year — down 11 from the 2014 estimate of 274.
The population had increased from 272 to 274 in 2014 following strong population growth in 2013, prompting a degree of optimism among biologists.
This year’s decline didn’t dramatically change the outlook.
“Squirrel populations can fluctuate considerably from year to year, and we aren’t immediately concerned with the lower squirrel numbers,” said Tim Snow, non-game specialist with the Arizona Game and Fish Department.
“Given the lack of cached cones we found during monitoring, we expected the population number to be lower than it was.”
Mount Graham red squirrels, which live only in the upper-elevation conifer forests of the Pinaleños, feed mainly on conifer seeds.
Snow explained how survey teams arrive at population estimates: “The red squirrel survey is conducted by visiting a random number of known middens — areas where red squirrels store or cache their cones. The activity rate is then extrapolated across the total number of known middens to determine the population estimate.”
The population of the species, which was declared endangered in 1987, peaked at about 550 animals in the late 1990s. It now typically ranges between 200 and 300 animals.”
Habitat losses resulting from fire, insect infestations and poor cone crops caused by drought are among the main factors influencing population size.
