Tick-carrying deer are living in the suburbs

White-tailed deer are heavily overpopulated along United States’ East Coast, and play a major role as vectors in the transmission of tick-borne diseases, such as Lyme or anaplasmosis. Until recently, efforts to control deer populations have been based on the assumption that deer live mostly in wooded parklands, and pass only occasionally through neighborhoods to graze on gardens and landscaped yards. 

However, according to a new longitudinal study led by the University of Maryland (UMD), deer spend much more time in suburban environments than previously thought, often passing their nights within 50 meters of residential properties. 

“We knew deer were in and around neighborhoods, but we didn’t realize just how much they were living in the neighborhoods,” said study senior author Jennifer Mullinax, an assistant professor of Wildlife Ecology at UMD.

“A big takeaway from this study is that neighborhoods are the home range of suburban white-tailed deer. Agencies monitoring and estimating suburban deer populations may be missing a huge part of the population if they focus their monitoring efforts only on deer in wooded parks and undeveloped areas, because a lot of the deer are actually living in the neighborhoods, especially at night and in winter.”

The scientists captured and collared 51 deer from five parks from the metropolitan area of Howard County, Maryland – a highly suburban area including residential neighborhoods, schools, businesses, and patches of undeveloped land. The collars contained high-resolution GPS trackers which recorded deer locations each hour for 62 to 116 weeks.

While deer tended to a avoid residential areas during the day, they often moved into them at night, particularly during winter, sleeping near the edges of lawns and yards surrounding houses and apartment buildings. “We used to think people mostly got Lyme disease when they walked in the woods,” Mullinax said. “But recent studies have shown they’re getting Lyme disease in their own backyards, and now that we know the deer are living right there too, it makes more sense.”

These findings offer important guidance for suburban communities seeking to reduce the risk of tick-borne diseases. Removing deer – which serve as tick reservoirs – or treating suburban areas where deer spend time could help limit the spread of tick-borne diseases and lower the rates of human exposure to this parasite.

The study is published in the journal Urban Ecosystems. 

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By Andrei Ionescu, Earth.com Staff Writer