Last Saturday, April 23, I had just left the parking lot at the J.J. Collett Natural Area when, all of a sudden, I saw what looked like a horse on the north side of the Natural Area fence. I quickly braked and reached for my camera, put it on zoom and snapped two pictures as it jumped the fence, bounded across the road in front of me, then jumped the fence on the south and disappeared into the woods.
It was a thin yearling cow moose that had a major infestation of Winter ticks, Dermacentor albipictus.
You can read about the life cycle of the Winter tick in the sources mentioned below, but basically, in the fall, young ticks crawl up grasses, then attach to a moose when it moves by. The ticks then live off the moose by sucking blood. In the early spring, the engorged ticks fall off and lay eggs. The following image is of the underside of an engorged female tick that has fallen to the ground.
The following two sources cover aspects of the life cycle of the tick and its effects on moose populations so well that I will not go into details here. By all means, read them.http://aep.alberta.ca/fish-wildlife/wildlife-diseases/documents/WinterTick-2004.pdf Samuel, Bill. 2004. White as a Ghost: winter ticks and moose. Federation of Alberta Naturalists. Vol. 1, Nat. Hist. Series. 99 pp.