I have a like/hate relationship with deer. On one hand it's pretty cool to have such a large mammal in your back yard. On the other hand they are disease-infested plant-eating machines.
They carry ticks and the associated Lyme disease. On our nature walk I picked up five deer ticks alone. Having already been treated for suspected Lyme once this year, I'd rather avoid that again. Still, it was to be expected - ticks and the regular inspections will become part of our life.
