In New Hampshire, what is the greatest tick mortality factor?

• A. Cold temperatures
• B. Predation by birds
• C. Drying out
• D. Humidity

Answer: (C)

Ticks in New Hampshire are extremely vulnerable to water loss, so drying out is the biggest killer they face. They live by the water balance—their bodies lose water to the environment faster than they can replace it when conditions are dry. That’s why they cling to moist microhabitats, like leaf litter and shaded spots, where humidity stays higher and water loss slows.

Cold temperatures do kill some ticks, especially when exposure is prolonged and they can’t seek protective microclimates, but many ticks survive winter by staying in moist, insulated spots under snow or debris. Predation by birds does occur, but it’s not the primary driver of mortality for ticks across the seasons. Humidity matters, but the critical factor is the actual drying out that results from low moisture; without enough moisture, ticks desiccate and die before they can find a host.