Inuvik (Mar 13/06) - Sunny skies are essential for survey work to begin on Cape Bathurst, Bluenose West and Bluenose East herds.

This month, the department of Environment and Natural Resources (ENR) will conduct a re-con survey for three caribou herds.

"We'll fly over the winter range using helio courier planes to find out where the caribou are on the winter range," said Marsha Branigan, ENR spokesperson.

Branigan is based in Inuvik and survey operations will be conducted from her office until mid-summer, when the photo census of the three herd populations can be completed.

With the Wildlife Management Advisory Council recommendations -- after consultation with the Gwich'in and Sahtu renewable resources boards - to stop all hunting except for subsistence harvesting, ENR is now charged with the task of conducting the most comprehensive survey of caribou to date.

"Once we have found where the caribou are on the winter range, we go out by helicopter and use net guns to capture caribou in order to collar the animals," Branigan said.

There are three types of collars used - GPS, VHF and satellite collars.

The GPS and satellite collars are the most effective, says Branigan, but ENR still uses radio-frequency collars.

"There will be 35 GPS collars used, 66 VHF collars and three satellite collars," Branigan said.

Surveyors will spread the collars out across the entire herd. Only the VHF collars will be going on the males because during the mating season, their necks enlarge and the collars fall off, says Branigan. Satellite and GPS collars will be used for the females.

In June, when the two herds travel to their calving grounds, located on Cape Bathurst and within the Tuktut Nogait National Park, surveyors will locate the collared animals.

"From there it's a waiting game," Branigan said. "We wait until the perfect day - a day where bugs are bad and it's really hot."

The herds bunch together on warm and buggy days, she explained, enabling surveyors to take the photos they need to determine herd populations.

Once pictures of herds are taken, a count is performed on a computer mapping program.

"It's not a complete count - it's an estimate and no matter what method you use, you can't count every single animal. It's impossible," Branigan said.

This year, more collars are being used than ever before.

"The photo census will let us know if the trend of declining populations is continuing," Branigan said. "The photo census method is also used in Alaska to count Porcupine populations and does give the most accurate picture in regards to caribou populations."