Deer over-population causes a range of problems including damage to seedlings in new-growth forests, the reduction in habitat they cause for smaller animals and the damage they cause to shrubbery in suburbs. Roaming deer are also a cause of traffic accidents.
In the USA it is reported there are more deer now than at the time when the Pilgrims landed in 1620. The 27 million roam through woodlands and into suburbs. In 1996 more than 100 people were killed in nearly 500,000 motor vehicle collisions with deer. In New York state the population of deer has risen from 300,000 in 1954 to one million in 1997, requiring an annual kill in the region of 200,000 to control the population size.