Moose Populations, Predators & Disease

How Ontario monitors moose

Ontario uses winter aerial inventories, hunter reports and other information to track populations and guide management. Aerial crews sample plots; they do not count every moose across the province each year.

Ontario’s public workbook separates observed moose, the animals counted during the survey, from projected moose, the estimated population. The dictionary defines the reported 90% margin of error as a percentage of the estimated mean.

Dated examples from the public workbook

These are the latest WMU-scale records for these three units in the file checked on October 14, 2026. Records at other survey scales are not substituted. The winter year may include surveying in December of the preceding calendar year.

The estimates are not exact headcounts or a camp ranking. Different dates, sampling and uncertainty limit comparisons. WMU 38’s 2019 figure is not a 2026 population claim.

Predators and parasites

Ontario identifies wolves and black bears among the predators affecting moose survival. The effect varies by place and age group; bears can take young calves.

Brainworm is normally carried by white-tailed deer. Moose can become infected by accidentally eating infected snails or slugs. The parasite can seriously damage the nervous system.

Winter ticks feed on moose blood. Heavy burdens and the rubbing that removes hair can cost energy late in winter. Ontario describes this as a survival concern when animals are already depleted.

Maine’s winter-tick research also links heavy burdens to calf survival and cow reproduction. Those results help explain the mechanism; they do not provide a tick rate for Ontario.

More than one cause

Habitat, food, weather, parasites, predators and hunting all belong in management decisions. Ontario also notes that heat stress can reduce feeding and affect condition.

A hairless patch or an unsteady animal is an observation, not a diagnosis. Record the location and date from a safe distance and ask the provincial wildlife office how to report a concern. Do not approach or try to handle the animal.

Keep local sightings in a notebook without turning a quiet week into proof of a province-wide decline. Use repeated surveys and their methods for that larger question.