ENDANGERED SPECIES -- Oregon wildlife officials say the state's wolf population increased at least 36 percent through 2015 to a minimum of 110 wolves.

The Oregon Department of Fish and Wildlife released its annual 2015 Wolf Report on Monday after completing late-winter surveys to establish how many wolf packs had bred and the minimum known number of wolves for the year 2015.

• The Washington Department of Fish and Wildlife is compiling a similar report as required under federal Endangered Species rules. That report is scheduled to be released in mid-March.

Oregon officials say they use hard evidence (tracks, sign, remote camera footage, visual observations) when counting wolves. "That is why the population figures are referred to as a minimum known population," they said on the agency's website. "Wildlife biologists believe the actual number of wolves is likely higher."

Oregon documented 11 breeding pairs of wolves in 2015, up from nine in 2014. A breeding pair is an adult male and female wolf that produce at least two pups which survive through the end of the year. (Pups are born in mid-April each year.)

Reproduction was confirmed in 14 groups of wolves, and 33 pups born in 2015 are known to have survived through Dec. 31.

Three new pairs of wolves were documented in 2015. Known wolf groups occurred in parts of Baker, Grant, Jackson, Klamath, Lake, Morrow, Umatilla, Union and Wallowa counties.

“As predicted, Oregon’s wolf population has continued to expand its range and grow in number,” said Russ Morgan, ODFW wolf coordinator. “While northeast Oregon continues to have the highest number of wolves, there is also continued movement of wolves into southern Oregon.”

The rate of livestock depredation by wolves decreased in 2015 despite the increase in wolf population.

ODFW investigations confirmed nine incidents of wolves killing livestock and two probable incidents. A total of 10 sheep, three calves and one working dog were killed by wolves, and another two calves and one lamb were injured. This is down from 11 confirmed incidents and 32 livestock (2 cattle and 30 sheep) lost in 2014.

A total of 29 percent of Oregon wolf packs were involved in livestock depredation.  The majority of depredations (77%) occurred on private land and most happened during the months of May, June, August, September. The Oregon Department of Agriculture’s Wolf Depredation Compensation and Financial Assistance program distributed $174,428 in grants to 10 counties to proactively address wolf-livestock conflict and compensate landowners who lost animals to wolves. Most funds were used for preventative measures ($119,390) and for direct payment ($14,018) to livestock producers for confirmed losses.

While no wolves were killed by ODFW, agents or landowners due to livestock depredation, ODFW documented seven wolf mortalities in 2015. A five-month-old pup was found dead in the Catherine Pack rendezvous area and appeared to die of natural causes. One wolf that died had a rodent in its stomach and the wolf tested positive for a chemical that is poisonous to animals. The cause of the death of the Sled Springs breeding male and female found dead in August is unknown. Three wolves were illegally shot.

A Baker City man pleaded guilty to shooting one of the wolves and was fined $2,000 and ordered to forfeit his rifle to the state.

ODFW continued its efforts to monitor Oregon’s wolf population by collaring an additional eight wolves over the year. At the end of 2015 there were collars on 11 percent of Oregon’s wolf population.