"Those very same bears we saw this morning have visited our snagging station," Darimont says. "We have their hair; we have their genetic code." I recall the four baited hair-snagging stations that I visited by boat with the field crew yesterday, as they dismantled the sites after completing the last sampling round of the field season. At each site, 25 meters of barbed wire stretches taught between trees at a level of 50 centimeters (the magic elevation apparently for getting snags from both little creatures that scooch under the wire and bigger beasts that step over it) forming a perimeter around a one-meter-high pile of brush drenched with a non-reward bait, a thick oily puree of rotted fish. Stand in the wrong place and the cloying smell of the bait decks your senses. I can only imagine how potent the aroma is when the stuff is freshly applied.
"Twelve days ago exactly we poured four liters of liquified fish, we call it our stink sauce, here," Darimont explained as the team got to work collecting the hair samples and dismantling the site. "Fun juice," Doug interjected, as he squatted on the forest floor to collect the hairs caught on the barbed wire. One hair on barb B7 was a bit thicker than the softer tufts of hair on the other barbs. "One nice guard hair," Doug said as he used his pliers to insert the hair into a tiny manila envelope.
The guard hairs (coarse, outer protective hairs) are a bonanza of information. Not only can genetic work on them be used to identify individual bears, but the researchers can also run isotope analyses to determine how much of the bear's diet in the previous year came from salmon. One of the Raincoast biologists and graduate student at the University of Calgary, Heather Bryan, has worked out a way to collect trace amounts of hormones from the hair, which will determine how stressed the bears were in the previous year, for example.
"It always amazes me," Darimont remarked as Doug Brown brought out his micro-jet blowtorch to sterilize the barb for next year's field season. "These can be 200- to 300-kilogram animals and from less than a milligram of material we can get species, sex, individual, establish what they've eaten, and if they might be stressed. It's like CSI in the rainforest." Darimont hopes to continue the study for years and even decades to come, citing some of ecology's iconic studies that link predator and prey such as Charles Elton's hare–lynx study or the ongoing moose and wolf study on Michigan's Isle Royale, the longest running continuous study of a predator–prey relationship.
So far the "stink sauce" has lured in 29 individual grizzlies and 68 black bears over two years. Darimont and his crew also know, from isotopic analyses, that between 65 to 95 percent of their grizzly bears' diet is derived from salmon—a remarkable percentage considering that the salmon are around for a mere two to three months of the year. "It shows you how important that resource is and it gives you a hint of how much bloody salmon they eat!" he says.
Another really interesting early story emerging from RCF's bear hair study is how black bears and grizzlies compete and cordon off their own dietary niches. When black bears co-habit an area with grizzlies, they are largely vegetarian, presumably deferring to the grizzlies' appetite for salmon. But black bears living on the inner islands, which are largely grizzly-free, eat far more salmon.
We've finally left the grizzly mother and her cubs behind. "These sort of experiences that we have had this morning carry us through, when it's a lot less sunny than this...or, worse, in the winter when we're in front of our computers," Darimont tells me over the roar of the wind on Wyatt, Raincoast's trusty 17-foot Olympic motorboat as we return to the RCF field station, located just across the water from Bella Bella, located on Campbell Island. "It's spell-binding to be in front of these animals in their home."