Sightings of ‘ghost moose’ have long been reported in the B.C. wilderness, and now a systematic effort to collect reports is showing an increase in winter tick infestation that drives moose to rub away their dark winter hair.
The second year of a B.C. government-led citizen reporting study collected more than 500 reports, mostly from Northern B.C. Province-wide, 61 per cent of moose sightings reported visible hair loss, up from 50 per cent in the pilot project year of 2015.
In the Skeena, 56 per cent of moose observed showed some degree of hair loss over the course of the winter – up from 49 per cent in the previous year.
Heavy tick infestation can be fatal to moose, causing them to lose much of their hair and take time away from feeding to groom or rub themselves during early spring when they are at their weakest.
As with mountain pine beetle and other bark beetles, winter tick populations rise with warmer conditions. Pregnant females have a higher survival rate because they aren’t dropping off into snow after engorging themselves on the host animal’s blood and laying eggs in spring.
The last major infestation in the B.C. Interior was noted in 1999, after unusually warm conditions the previous year. Cold fall temperatures and early snow can also reduce ticks at their larval stage.
Winter ticks also affect whitetail and mule deer, elk and bison, but mainly moose.
Contrary to the black-legged tick, which can transmit the bacteria responsible for Lyme’s disease to humans, the winter tick does not carry diseases that can be transmitted to humans.
Based on 2016 snow data, the survey predicts increased tick severity in 2017 for the Skeena and Omineca regions. Biologists are entering the third year of the study and need to collect more data before they can get an accurate picture of winter tick prevalence.
Winter tick infestations are generally observed on moose from February through April. The tick monitoring program is publicized through local newspapers and radio, outdoor magazines and distribution to conservation officers, wildlife biologists, hunters, trappers and the general public.
Responses from the public have increased after the pilot year.