By Jan McCoy Hutchinson

Since becoming director of the Mount Graham Red Squirrel Monitoring Program in 2002, John L. Koprowski has broadened the group into an active research unit whose highly successful marking and monitoring efforts are already producing deeper insights into this endangered species.

"We're doing extraordinarily well," Koprowski says. "We've marked 104 animals without a single injury and at least 90 percent of the red squirrels in the study area are marked. We've caught squirrels about 600 times, which is an average of six captures an animal. Some researchers have spent as much as 200 days trying to capture a single squirrel.

Koprowski is an associate professor of wildlife science in the UA School of Renewable Natural Resources. Before joining the UA, he was an associate professor of biology at Willamette University in Salem, Ore.

The last century brought logging, hunting, non-native squirrels, recreational development, fire, drought and insect infestations to southeastern Arizona's Pinaleno Mountains. Not surprisingly, the unique red squirrel population that had lived atop the mountain island for 10,000 years went from abundance in the 1880s, to supposed extinction in the 1950s, rediscovery in the 1970s and federal listing as endangered in 1987.

The Red Squirrel Monitoring Program began after the 1988 Arizona-Idaho Conservation Act permitted construction of the Mount Graham International Observatory in critical red squirrel habitat. The act required the University of Arizona Steward Observatory to fund a program to monitor the impact of the observatory on the squirrel population through the life of the observatory. Since 1989, the monitoring program has tracked the population within about 1,000 feet of the observatory and access road, and two non-construction areas for comparison. The monitored area includes mixed-conifer forest and spruce-fir forest, ranging in elevation from about 7,800 feet to 10,720 feet respectively. The number of red squirrels in this area has varied from a low of 27 to a high of 229.

"When I arrived here, the monitoring program was focused heavily on answering the question, ‘How many?'" Koprowski says. "We still do that, but my goal has been to change some of the focus to start answering some of the ‘Why?' questions. To try and predict the future of this squirrel population, we need to know important parameters such as survival and reproduction, which we really didn't have a good handle on during the first 10 years or so of the project."

Learning which animals are surviving and reproducing is impossible without marked animals to monitor, so Koprowski got the live capture and marking program up and running soon after his arrival at the UA.

Past squirrel researchers had done some live trapping and marking of red squirrels but catching the animals proved challenging. Although their territorial behavior and large middens, or food caches, make red squirrels easy to spot, they are hard to catch.

Koprowski's success is the result of years of experience working with many other squirrel species. In fact, except for the Arizona gray squirrel that lives in the mountains outside Tucson, Koprowski has captured and handled every species of tree squirrel in North America for a variety of conservation- oriented activities.

"You could say I am a little more sensitive to the ‘needs' of the squirrel," he says, grinning. "I have a good sense as to the kinds of things squirrels are attracted to and the kind of sites where you might find them."

The capture and marking process begins by introducing the red squirrels to a novel food, a few peanuts or a dab of peanut butter, during the winter when little food is available. On subsequent visits, the researchers bring Havahart®-like live traps wired open for easy access to peanuts inside. Only occasionally do the researchers set the live trap and catch the squirrels. The same capture method works with juvenile squirrels, which are easy to catch during the two-week window when they first emerge from the nest to explore. After two weeks, Koprowski says, these juveniles leave and are rarely seen again.

The big problem with catching tree squirrels can be trap shock.

"In some studies, more than 20 percent of captured animals died," Koprowski says. "Reaching into the trap and drawing the squirrel out is a bad idea. There's a high level of shock that occurs when something 200 times your size grabs you and starts pulling on your ears."

To prevent shock, the monitoring team uses a Koprowski-designed cloth handling cone that takes advantage of a squirrel's natural response to run for cover when threatened. When researchers open the live trap into the cone, the squirrel runs out and dives nose first to safety at the narrow end. That end is secured with a Velcro® closure that opens just enough to allow radio collaring or marking with colored ear tags.

"Squirrels seems to equate having their eyes covered with safety," Koprowski says. "When their eyes are covered, their heart rates drop and they calm down incredibly."

Koprowski says earlier researchers working to live trap and mark red squirrels operated with some restrictions placed on them by the Fish and Wildlife Service, in part, because a couple of squirrels died in the early attempts to learn more. He says the device the researchers were required to use did not cover the animal's eyes, making them much more susceptible to shock.

Overall, most of the marked squirrels in the study area are unafraid of the live traps or "trap happy," since from their perspective, Koprowski says, the free food is a pretty good deal.

Of course, a few are always hard to catch. Koprowski says one male squirrel took nearly a year to catch because "he just wasn't interested in peanuts."

Has this wily male become the granddaddy of the Mount Graham red squirrel population?

"No," says Koprowski, "he was picked off by a hawk, which is their fate."

One new piece of information emerging from the monitoring program is the high mortality rate from predation by hawks and owls. Along with the ability to follow the movements and interactions of radio-collared squirrels from a distance, the researchers can also find dead squirrels, or what remains of them at the base of a tree.

"Earlier monitoring data showed an overwinter survival of about 50 to 60 percent, but we never knew what happened to those who didn't survive," Koprowski says. "We now know that about 85 percent of the red squirrel mortality is due to raptors, most of which occurs in the fall and the winter when many avian predators are migrating. The squirrels are nice packets of protein for raptors when nothing else is active above ground."

Having marked animals also makes it easier to find nesting sites. Since less than 10 percent of the squirrels caught in the monitoring study area are young, Koprowski wants to know where the young squirrels go when they leave their nests.

"Are they all dying?" he says. "Probably not. Some are finding other places to live, maybe most of them are. We don't know that part of the puzzle either."

Koprowski says finding the places squirrels find attractive to settle in could provide key information about "what really is quality habitat." Early on, the higher-elevation spruce on Mount Graham was considered the main habitat of the red squirrel, but the squirrels live in both the spruce and mixed conifer forests.

"The spruce may be the prime habitat, but there has been incredible insect damage to the spruce forest and almost all of it is gone. Much of that habitat is lost but yet we still have squirrels."

Since 1991, biologists and volunteers from the Arizona Game and Fish Department, the U.S. Department of Agriculture Forest Service, the U.S. Fish and Wildlife Service and the UA have conducted spring and fall surveys of the red squirrel population. The fall 2003 survey estimated that a range of 274 (plus or minus 13) red squirrels currently occupy the Pinaleno mountain range. These results are slightly higher than the Fall 2002 survey results of 269 (plus or minus eight) red squirrels.

For the future, Koprowski says the monitoring program will continue monitoring yearly squirrel survivorship and productivity with the focus of answering more "Why" questions.

"We want to get to the point where we can start to think about what the future holds for the red squirrel population," Koprowski says. "Right now, we're playing catch up, trying to figure out what is and has been going on there. Once we've gathered more basic data, we'll be able to get into more details."