A contraceptive vaccine for deer, which lasts for five years, has been developed by researchers in the United States. One of the researchers says it isn’t a comprehensive solution to the problem of growing deer populations, “This alone can’t bring a population down in a reasonable amount of time; it can manage the population that’s there.” (Source: BBC) Only Maryland and New Jersey have licensed the vaccine so far. The contraceptive vaccine might also work on squirrels, wild horses, and animals like stray cats and dogs.
One of the main ways large deer populations are controlled is through annual hunts. New Jersey has increased the duration of its deer hunts, and bag limits. They have also tried chemical fertility control, but it is labor-intensive and not practical for very large free-roaming populations. A study in New Jersey found $13 million in damages were caused by deer overpopulation. Other research has found large deer populations can eat so many plants, there aren’t many left for other animals, so they can’t live. Last year in Maryland, about 99,000 deer taken in the hunt. The total population has been estimated to be about 231,000. About 8,000 died in vehicle accidents last year. A survey of the Maryland public found about 61% were in favor of using hunting as a deer population control. Chronic wasting disease has been found in deer in states near Maryland, such as West Virginia, and Virginia. In 2005 Ohio deer-car collisions caused an estimated $71 million in damages.
One of the reasons there are so many deer is the removal of natural predators from habitats where deer live. Mountain lions, coyotes, and wolves no longer occupy their once-natural ranges, and are often killed deliberately when they do, or are killed by accidents with vehicles.