Larvae molt over the winter and emerge as tiny, poppy-sized nymphs in the spring. Nymphs are no bigger than the period at the end of this sentence. When they take a second blood meal, typically in the months of May through July, infected nymphs can transmit disease to the humans or animals they feed on. This is the peak season for contracting Lyme disease. The nymphs become adults in the late summer and are active in the fall, winter and spring whenever the temperature is over 35 degrees.
Mild winters make ticks a year round threat.
Adult ticks are easier to see than nymphs and are usually seeking the deer as their third host. However, since they have taken two blood meals they are twice as likely to be infected and are more capable of transmitting disease should they bite a human or pet. The number of ticks in an area is directly related to the number of deer. The more often deer frequent one's yard, the more likely it is that ticks will be deposited. However, it is the birds, mice, and other rodents, not the deer, which are responsible for the transmission of disease.